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Drug, Alan Harding London, Albert Einstein, Alison Flood Senior, Alison George, Amardeep Sian, Analysis Artificial, Ancient Egyptian, Aperture Haunting, Archaeology
Ancient Egyptian
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天文学家首次在太阳系之外的一颗岩石温带行星上检测到了大气层。这是目前证明一颗系外行星可能能够支撑外星生命的最有力证据。这颗被称为 LHS 1140b 的行星围绕着一颗名为 M型矮星 的小型冷恒星运行，距离地球约 50 光年。几十年来，研究人员一直在 M型矮星 周围寻找被大气包裹的行星，因为它们是银河系中最常见的恒星类型，但直到现在才获得成功——有些研究人员甚至假设，这些小恒星周围的行星可能无法保留大气层。
但当哈佛大学 (Harvard University) 的 Collin Cherubim 及其同事在 2024 年于智利 (Chile) 的拉斯坎帕纳斯天文台 (Las Campanas Observatory) 观测 LHS 1140b 时，他们发现了一个极具希望的信号：行星光谱中的一条线表明存在处于激发能态的氦原子。对此有几种可能的解释，但信号的形状和强度使他们得出结论：这些氦气是外流的一部分，正从行星大气层中泄漏 (Science, doi.org/hcbwhf)。“到目前为止，最简单的解释就是我们看到的这些氦气来自行星本身，”Cherubim 说道。这将使 LHS 1140b 归类为“氦世界”，这是一种已被提出但尚未被明确检测到的系外行星类型。“这与我们根据自身太阳系中的岩石行星所预期的不同，”马里兰州约翰霍普金斯大学 (Johns Hopkins University) 的 Natalie Allen 说道。
[[IMG_XXXX]] LHS 1140b，此处为艺术想象图，围绕一颗 M型矮星 运行
星际空间中发现的复杂糖类
虽然在系外行星上检测到大气层暗示其他世界可能具备支持生命的条件（见主报道），但在星际空间中发现复杂糖类分子的发现，则揭示了生命的构建基块是如何在银河系中传播的。
某些糖类是 核糖核酸 (RNA) 和 脱氧核糖核酸 (DNA) 的基础构建基块，而这些遗传物质存在于每个活细胞中。近期在陨石和小行星样本中发现的糖类表明，此类天体可能将它们带到了早期的地球。马德里 (Madrid) 天体生物学中心 (Centre for Astrobiology) 的 Izaskun Jiménez-Serra 及其同事想知道，糖类是否也存在于星际空间本身。为了查明这一点，他们将射电望远镜对准了 G+0.693−0.027，这是一个距离 26,700 光年、已知含有数十种有机分子的巨大分子云，其中包括乙醇醛——一种参与糖分形成但本身不被视为真正糖类的化合物。
该团队将分子云的射电辐射与实验室测得的光谱指纹（分子吸收和发射射电频率的独特模式）进行了对比，对比对象为最简单的糖类：甘油醛 (Glyceraldehyde) 和 二羟基丙酮 (Dihydroxyacetone)。
当这两种三碳糖的结果均为空时，Jiménez-Serra 表示她决定检查一种四碳糖——赤藓酮糖 (erythrulose)，这是覆盆子中发现的糖类之一。令她惊讶的是，团队发现了极其丰富的该分子供应 (Nature Astronomy, doi.org/rf25)。“这些分子云基本上是恒星和行星的诞生地，”她说道。“所以从本质上讲，我们发现这些对生命起源至关重要的复杂有机化合物，在行星系统的形成过程非常早期就已经形成了。”
荷兰代尔夫特理工大学 (TU Delft) 的 Niels Ligterink 表示，在冷却至约 -250°C 且受到强烈辐射轰击的冰尘颗粒上，发生了一些在地球上自然界中从未见过的化学反应，这些反应可能产生了最终导致生命诞生的某些分子构建基块。“我们现在可以说，生物化学的原料可能分布在整个银河系中，”他说道。
Christa Lesté-Lasserre
在某些方面，一个氦世界可能比太阳系中的任何类地世界都更像气态巨行星，其岩石或冰层表面覆盖着一层厚重的大气层。
“就其本身而言，这非常令人兴奋，而不是将其视为一个新的地球，”亚利桑那大学的 Sukrit Ranjan 表示。“它可能是宜居的，但并非传统意义上的宜居。”
如果它确实拥有厚厚的大气层，其表面的压力可能与地球海洋底部的压力相似。如果不是这样，它有可能是一个海洋世界，与我们太阳系中的冰卫星更为相似，而非与任何行星相似。
目前，我们知道这个世界拥有一个似乎在泄漏氦气的大气层，但我们对其大气层本身的规模和成分知之甚少。“地球和金星在尺寸上非常相似，且都拥有大气层，但金星的表面并不宜居，”Allen 表示。“我认为，要真正了解其宜居性……”
“ 这颗行星现在 已成为在太阳系外 寻找生命的最佳地点”
MELISSA WEISS/哈佛大学 & 史密森尼学会天体物理中心
“在这颗行星上，我们需要了解其整体大气层。” 她说，尚未公布的来自詹姆斯·韦伯空间望远镜的数据可能有助于阐明这一点。
Missing signature
然而，大气的存在，以及 LHS 1140b 绕其恒星运行在所谓的宜居带（该区域温度温和，足以在其表面保留液态水）这一事实，使其具有极大的潜力。“这颗行星现在已成为在太阳系之外寻找生命的最佳场所，”Cherubim 说道。
不过有一个注意事项：当 Cherubim 和他的同事在 2025 年使用相同的设备再次观测 LHS 1140b 时，他们没有看到特征氦谱线。他们仔细研究了 2024 和 2025 的数据，咨询了其他研究人员，并由另一个独立团队重新分析了数据，结果依然相同：激发态氦在 2024 年存在，但在 2025 年不存在。
Cherubim 表示，这令人惊讶，但并非完全异常。“当你对逃逸氦进行测量，然后在数月或数年后再次观察时，结果通常会不同，有时它甚至不在那里——而我们对此并不理解，”他说。
Ranjan 指出，这种特定的氦特征尚未被充分理解，因此我们无法确定它为何会出现随后又消失。有可能是流出的形状发生了变化，或者是恒星活动的改变改变了流出物中氦的性质。如果氦仍然存在但不在激发态，我们预计其特征会消失。Cherubim 计划继续观测 LHS 1140b，试图解开这个谜团。 ❚
神经科学
瘫痪的手部仍有感觉
Christa Lesté-Lasserre
一名在六年前潜水事故中导致瘫痪的男子，得益于大脑刺激，重新获得了移动以及感知手部压力的能力。现在，研究人员透露，在刺激停止后的数月时间里，他依然维持着这一能力。
“我们完全关闭了所有设备，持续了数月之久，但他的这些功能提升依然在维持，”纽约 Feinstein 医疗研究中心的 Chad Bouton 说道。“这简直闻所未闻。”
Keith Thomas，48 岁，在 2020 年 7 月起从胸部以下瘫痪。Bouton 表示，他当时失去了对肢体的感觉和控制，且出现了严重的肌肉萎缩。
2023 年，Bouton 及其同事为 Thomas 进行了双神经旁路手术，在他的大脑中与手臂运动和感觉相关的区域植入了五枚电极。他们将计算机电缆连接到这些电极上，以便人工智能能够解读他的运动意图。随后，这些信息被传输到电子夹板中，刺激他的手臂、手掌和手指以执行预想的动作，使他能够拿起咖啡杯并挠脸。
为了重建触觉，团队在为 Thomas 的手部和手指设计的 3D 打印可穿戴设备中嵌入了压力传感器，通过电刺激将反馈发送到大脑的感觉区域。
Bouton 表示，在进行一系列实验后，团队计划停止刺激大约一个月，以测试是否存在任何持久影响。
“然后大楼里发生了火灾，这实际上迫使我们停止刺激的时间比计划的更长，大约持续了三个月，”他说道。
这次意外的中断导致了令人惊讶的发现：Thomas 的手部力量、感觉和功能得以维持（《自然-医学》/ Nature Medicine, doi.org/hcbwnc）。“他现在控制单个手指的精准度甚至更高了，这意义重大，”Bouton 说。
在接受《新科学家 (杂志)》的视频采访时，Thomas 将肘部抬高至接近肩膀的高度，并描述在受到压力时，即使在“未连接计算机”的情况下，手腕仍有“刺痛感”。“当我第一次感觉到时，太神奇了，”他说。“我现在已经习惯了。”
加州大学戴维斯分校的 Sergey Stavisky 表示，这项工作表明，该方法能促进神经系统的持久恢复。
“目标是帮助神经系统部分痊愈，以便患者能更好地活动自己的身体，”他说道。
“如果即使在系统关闭时，这些改善依然存在，那么该设备所起的作用就不仅限于临时恢复功能，”加州大学洛杉矶分校的 Daniel Lu 表示。“它可能正通过神经可塑性帮助神经系统实现自我重组。”
这描述了大脑通过形成新的神经连接来重新构建自身的能力，例如在受伤后，甚至在接触新爱好时。
但这仅是一个单例报告，因此尚不清楚这种方法在其他因不同类型损伤而瘫痪的人群中效果如何。
“这是一项非常有野心的研究，但我们需要看到他们在更多参与者身上复制出同样的结果，”芝加哥大学的 Charles Greenspon 表示。 ❚
物理学
关于意识具有量子起源这一极具争议的观点正面临一项新挑战，因为一项数学分析表明，一项众所周知的物理定律使得这一观点在现实中不可行。
究竟什么样的物理过程让我们产生了意识，以及我们是否能够观察并分析这一过程，是现代科学中伟大的开放性问题之一。在 20 世纪 90 年代，数学家罗杰·彭罗斯 (Roger Penrose) 和麻醉学家斯图尔特·哈梅罗夫 (Stuart Hameroff) 提出，仅凭经典物理学无法解释意识，因此它必然产生于量子领域。这一观点在当时受到了质疑且至今仍充满争议，但将“量子性”引入意识解释的尝试自此一直存在。
现在，加州查普曼大学 (Chapman University) 的艾米莉·阿德拉姆 (Emily Adlam) 及其同事研究了纯量子主体性 (quantum agency) 的观点——这是意识的前提条件——并发现它行不通。
意识极其难以定义，但该团队利用清晰的物理要求，为“主体性”制定了一个最简定义。量子意识理论，即使它们聚焦于大脑中的特定机制（如彭罗斯和哈梅罗夫的提案），如果要具有可信度，就应当与该定义兼容。
具体而言，研究人员聚焦于一个主体的模型：该主体观察世界，创建世界模型，然后利用该模型在决定执行某项行动前，评估不同可能行动的结果。“这其中会有一个从环境中提取你将要响应的信息步骤，然后是某种[信息]复制
量子主体性
关于意识的量子本性 自 20 世纪 90 年代起 一直被人们争论
步骤，以便你可以考虑不同的可能选项，最后是一个比较步骤，你查看每个模型的输出，决定哪个是最好的，并以此引导你的行动，”阿德拉姆说。
但如果该主体是量子的——也就是说必须遵循量子力学定律——那么复制步骤是不可能的。这是因为“不可克隆定理” (no-cloning theorem)，该定理指出，描述系统所有信息的量子态无法被复制或复制。
阿德拉姆表示，主体可能会尝试通过创建所需审议信息的“不完美副本”来处理这个问题，但随后会产生其他问题。例如，从世界中提取量子信息会改变世界，因此主体的世界模型实际上反映的是一个略有不同的世界。虽然我们在模拟世界时总会存在某种程度的不完美，但这些缺陷会产生累积效应。
比较步骤同样受到“量子怪异性”的影响。阿德拉姆说，这是因为纯量子主体只能使用量子信息处理，而这提供的处理过程与我们习惯的不同。“一个现实的量子操作最终会产生所有可能选项的某种奇特的叠加，并向更好的选项倾斜。你实际上并没有执行最佳选项，而是执行了所有选项的这种诡异组合，”她说。
团队成员、同样就职于查普曼大学的凯尔文·麦奎恩 (Kelvin McQueen) 在 6 月 17 日于加州欧文举行的“物理学基础” (Foundations of Physics) 会议上发表演讲时表示，这些结论挑战了关于主体性、自由意志和意识的量子理论，同时也给量子计算机未来可能模拟的任何主体带来了技术限制。
“这些结果帮助我们理解，在一个否则由量子力学主导的宇宙中，主体性和类人感知是如何产生的，”他说。
“更有可能的是，这些现象源于，或至少由经典机制主导”
YANA ISKAYEVA/GETTY IMAGES
事实上，研究人员所指出的纯量子智能体存在的问题，使得人们更难证明 agency（能动性）和意识在本质上都采用了量子机制。Adlam 表示，这些现象更有可能是由经典机制产生，或者至少由经典机制主导。“在某些情况下，进行量子计算或许能带来加速，但这无疑使得整个能动性过程看起来基本上是建立在经典领域之上的，”她说道。
澳大利亚昆士兰大学的 Sally Shrapnel 表示，既然量子物理是我们目前拥有的最好的物理理论，那么从这个视角去探究能动性的样子是有意义的。她指出，研究人员的能动性模型是基于一种对量子世界中本质真实的特定解释。她认为，如果将量子态不视为现实的理想化构建模块，而是将其视为反映我们对世界认知的事物，那么量子能动性模型可能会具有更少的约束。例如，可以将一个智能体建模为与环境不断交互，并动态地收敛于一个决定，而不是在不同的世界模型之间进行权衡，这将允许经典和量子信息处理的混合。Shrapnel 表示，现有的量子意识理论并不像这项新研究的模型那样死板地局限于量子化，因此它们可能还没有被完全排除。 ❚
衰老
僵尸细胞或可 改善衰老
Isha Ishtiaq
随着年龄增长，我们的身体失去了清除那些停止分裂的“僵尸样”细胞的能力，而这些细胞会滴出毒素并使其他细胞变异。恢复清除这些“衰老”细胞的能力，可以防止年长小鼠出现认知能力下降和衰弱的迹象，并暗示人类可能会出现相同的结果。
加利福尼亚州斯坦福大学的 Katrin Andreasson 及其团队将 6 到 8 个月大（大致相当于 20 多岁的人类）的小鼠与 23 到 25 个月大（相当于 60 或 70 多岁的人类）的小鼠进行了比较。他们发现，年长小鼠的器官（包括肝脏和脾脏）以及骨髓中含有更多这类衰老细胞。
这些衰老细胞是中性粒细胞，它们通常是身体对抗感染的第一道防御防线。通常情况下，这些细胞会被驻留在组织中的巨噬细胞清除，巨噬细胞负责清除受损细胞和碎片，但这种能力随年龄增长而下降。
[[IMG_XXXX]] 年长小鼠的脾脏中 含有更多僵尸免疫细胞 ROSSANA MELO/SCIENCE PHOTO LIBRARY
Andreasson 及其同事将这种下降追溯到前列腺素 E2，这是一种随年龄增长而增加的信号分子。他们发现，较高水平的前列腺素 E2 活动会过度刺激组织驻留巨噬细胞上一个名为 EP2 的受体，导致它们清除衰老细胞的能力降低。
接下来，该团队通过基因改造年长小鼠组织驻留巨噬细胞中的 EP2 基因，测试阻断这种过度刺激是否能改善衰老迹象。与同龄的未改造小鼠相比，这些动物能够清除更多衰老的中性粒细胞，并显示出更健康的衰老迹象，包括炎症水平较低、肌肉流失减少以及更好的活动能力。
“恢复清除僵尸细胞的能力 防止了认知能力下降的迹象”
在记忆力测试中，它们的表现也几乎与年轻小鼠一样好。
研究人员还测试了一种阻断 EP2 受体蛋白的实验性药物。当给年长小鼠口服两个月后，该药引起了与基因改造小鼠类似的年龄相关改善（Science, doi.org/rgfp）。
最后，该团队在人体组织中发现了类似的模式，年长者的肝脏样本显示出更高的 EP2 受体活动和更多衰老的中性粒细胞。伦敦大学学院的 Derek Gilroy 表示：“人体数据提供了支持，但仍是相关性的。我们还没有证明阻断 [EP2 受体] 可以恢复年长人体组织中的中性粒细胞清除能力。” ❚
考古学
发现于挪威
James Woodford
MAGNE SAMDAL，奥斯陆大学文化历史博物馆
至少 7000 年前，狩猎采集者将褐鳟运送到挪威山区，以便在夏季前往高地的旅途中进行捕捞。挪威奥斯陆大学的 Axel Mjærum 表示，这是解释鱼类如何进入那些曾被数公里厚冰盖覆盖数万年的孤立山区的唯一原因。“这是世界上已知最早的人为介导鱼类迁徙的记录案例，”他说道。
直到大约 8400 年前，海拔约 850 米的 Tesse 湖仍被芬诺斯堪地那维亚冰盖覆盖，在冰盖退却后留下了一片生态空白。然而，直到 20 世纪 40 年代，Tesse 湖一直被认为是挪威褐鳟资源最丰富的水域之一，每年产鱼 9 吨。
虽然人们长期以来一直怀疑人类在建立 Tesse 湖的褐鳟种群中起到了作用，但我们并不清楚这具体发生在何时。Mjærum 和他的同事们研究了在湖水位降低时于 2022 年发现的被部分掩埋的复杂木制鱼陷阱遗迹。
Before farming started in Norway, people made fish farms in Lake Tesse （在挪威开始农耕之前，人们就在 Tesse 湖建立了鱼类养殖场）
放射性碳定年法显示，最古老的陷阱可追溯到公元前 4950 年左右。通过将回收的木材与松树年轮年代学相结合，该团队能够对部分较新陷阱的支柱进行精确测年。其中一根来自一棵在公元前 2669 年春季至公元前 2669-2668 年冬季之间被砍伐的树，另一根则在 12 年后的公元前 2657-2656 年冬季被砍伐，这证明这些陷阱必须经过维护才能保持良好的工作状态（《古物》/ Antiquity，doi.org/rgfq）。Mjærum 表示：“这种陷阱捕鱼形式可能在公元前 5000 年至 2650 年之间的大部分时间里都在 Tesse 湖持续进行。”
将鱼类运输到湖泊中是人类通过管理环境来提供食物的早期案例，这比斯堪的纳维亚半岛出现农耕早了几个世纪。人们是如何移动这些鱼的目前尚不清楚，但他们可能使用了水囊。Mjærum 认为，人们当时可能在夏季的一部分时间里留在山中，捕猎驯鹿并钓鱼。 ❚
健康
Michael Le Page
治疗多发性硬化症 (MS) 最佳的疗法可能是针对 Epstein-Barr 病毒的抗病毒药物。哈佛大学医学院的 Michael Levy 表示：“目前还没有效果良好的 Epstein-Barr 病毒药物，但它们是可以研发出来的。这可能是未来治疗 MS 最有用的特异性疗法。”
MS 是由于免疫系统攻击髓鞘（包裹在神经周围的脂肪层）而引起的。髓鞘的缺失会降低神经传输信号的能力，并可能导致包括肌肉无力在内的广泛症状。抑制免疫系统的药物可以减缓该病况的进展。有强有力的证据表明，导致传染性单核细胞增多症（或称腺索热）的 Epstein-Barr 病毒 (EBV) 也是 MS 的诱因。但具体机制仍是一个谜。
几乎每个人在成年之前都会感染 EBV。它主要感染被称为 B 细胞的免疫细胞，并在其中潜伏于人的终身之中。但在某些细胞中，该病毒可能会重新激活。
[[IMG_XXXX]] 在 MS 中，一些大脑免疫细胞攻击神经细胞 PROFESSOR JOHN ZAJICEK/SCIENCE PHOTO LIBRARY
一个巨大的疑问是，既然几乎每个人都会感染 EBV，为什么只有大约 1/1000 的人会发展为 MS。马萨诸塞州总医院的 Natalia Drosu 表示，这表明在那些最终发展为 MS 的个体中，对 EBV 的免疫反应存在某种差异。
在一项新研究中，Drosu 及其同事将重点放在了在体内循环的名为 CD4 T 细胞的免疫细胞上。Drosu 称，这些细胞并不直接攻击髓鞘，但它们似乎在 MS 中发挥了某种作用。
他们发现，在 30 名 MS 患者中，大多数针对 EBV 的 CD4 T 细胞专门针对病毒在积极复制时产生的病毒蛋白，而非与其潜伏阶段相关的蛋白。平均而言，MS 患者产生此类细胞的数量是 30 名非患者的两倍。
研究人员随后观察了 60 名 MS 患者在开始使用旨在降低 B 细胞数量的药物治疗前后的 T 细胞情况。他们发现，这些治疗将对 EBV 的 T 细胞反应降低到几乎与非 MS 患者相同的水平。
该团队还发现，这些患者在治疗前的唾液中含有低水平的 EBV，这表明病毒在他们的体内正在复制。治疗后，大多数人的病毒水平下降到了检测限以下 (Science Translational Medicine, doi.org/rf2t)。
“Epstein-Barr 病毒药物可能是未来治疗 MS 最有用的特异性疗法”
Levy 表示，之前的观点认为 B 细胞在 MS 患者体内推动了有害的免疫反应，这就是为什么降低 B 细胞水平的药物有效。但他说，结果表明这些药物通过清除被 EBV 感染的 B 细胞来发挥作用，从而减轻了由病毒积极复制引起的免疫反应。“我们认为，清除 B 细胞同时也清除了 Epstein-Barr 病毒的蓄水池。”
如果真是这样，使用抗病毒药物直接针对 EBV 可能会与清除 B 细胞的药物一样有效，但不会产生削弱免疫系统治疗所带来的不良副作用，例如感染风险增加。
团队成员、哈佛 T.H. Chan 公共卫生学院的 Kjetil Bjornevik 表示：“我认为许多患者会更倾向于使用一种特异性药物。如果我们能证明一种抗病毒药物具有与最有效的 MS 药物相似的效果，我认为这种药物将有巨大的市场。” ❚
口腔健康
与牙龈 刺激相关
Mattha Busby
尼古丁袋可能会导致牙龈退缩，以及不适感和发红。这是首项研究尼古丁袋相对于鼻烟（snus）对口腔黏膜影响的研究得出的结论。由于鼻烟含有烟草，通常被认为危害更大。
无烟草尼古丁袋近年来人气激增。这些小药袋放置在上唇下，与鼻烟类似，后者是一种有时通过药袋使用的粉末状烟草。鼻烟与口腔刺激和心脏相关死亡有关，但关于尼古丁袋的了解较少。
现在，瑞典卡罗林斯卡学院（Karolinska Institute）的 Karin Legert 及其同事研究了 272 名 18 至 30 岁的成年人，其中 126 人使用尼古丁袋，63 人使用鼻烟。他们每天使用产品五次或更多次，且持续至少三个月，但不使用任何其他尼古丁或烟草产品。研究人员还观察了 83 名不使用尼古丁袋、鼻烟或任何相关产品的个体。
他们观察到，在尼古丁袋使用者中，有 45% 出现了牙龈退缩（这会使牙齿敏感的根部暴露出来），鼻烟使用者中为 52%，而非使用者中为 6%。这种退缩通常发生在使用者习惯放置药袋或鼻烟的区域（《口腔疾病》/ Oral Diseases, doi.org/hb959h）。
研究人员还发现，尼古丁袋似乎比鼻烟引起更多的牙龈刺激，例如发红和不适。Legert 表示，这可能是因为它们通常含有添加口味，而这“可能会导致刺激、上皮细胞损伤和炎症反应，特别是在敏感的口腔组织中”。Legert 指出，使用者最喜欢的口味是薄荷味，而薄荷味通常由“化学成分的复杂混合物以及合成冷却剂”组成。 ❚
技术
乌克兰开发了一款廉价的巡航导弹，由一种通常见于消费级无人机的开源自动驾驶系统引导。业余组件的使用凸显了军事电子产品与消费电子产品之间日益缩小的差距，这可能使小国和非国家行为者更容易开发强大的高科技武器。
由于难以获得外国远程武器，乌克兰不得不自行开发。乌克兰公司 Fire Point 上个月在巴黎的 Eurosatory 国防展上展示了其 FP-5 Flamingo 巡航导弹。这款 6 吨重的导弹可以携带比“战斧”巡航导弹重两倍的弹头，飞行距离也增加一倍，但成本仅为后者的极小一部分。
Flamingo 低成本的秘诀之一在于其 Ardupilot 飞行控制器，该控制器利用传感器数据使导弹沿着预定路径稳定飞行。Ardupilot 是一套自 2009 年起就存在的开源软件套件，可以在成本低于 $100. 的硬件上运行。无人机爱好者将 Ardupilot 应用于从多旋翼机、模型飞机到船只和地面车辆的各种设备中。
FIRE POINT
隐形无人机旋转速度极快以至消失
随着业余无人机组件被应用到更大的巡航导弹中（见主报道），一种新型无人机被创造出来，它以一种不寻常的方式规避探测：通过极速旋转使其模糊在背景之中。这款名为 Phantom Twist 的无人机由伊利诺伊州西北大学的艾玛·亚历山大（Emma Alexander）及其同事研制。它每秒旋转 25 转，像风扇叶片一样通过运动模糊将自己隐藏起来。但与
“小国现在能够制造出几乎与资金充足的邻国能力相当的武器”
Fire Point 的首席技术官伊琳娜·特列赫（Iryna Terekh）在 X 平台的一篇帖子中表示，开源软件提供了独立性，因为它不来自可能破产或被禁止向乌克兰出口的公司。此外，一个由数千名工程师组成的社区能够快速发现并
风扇（风扇有保持可见的固定部件）不同，Phantom Twist 的每一个部件都在旋转。亚历山大说：“运动模糊基本上将所有机械部件变成了这种轻微的薄雾。如果你不注意，你真的可能会忽略环境中亮度的那种轻微变化。”这种单电机设计是通过涉及三个 人工智能 模型的自动化过程选出的。
修复软件中的漏洞。非营利组织“乌克兰国防技术”（Defense Tech for Ukraine）的罗伊·加丁纳（Roy Gardiner）表示：“使用开源的 Ardupilot 符合 Fire Point 的整体理念，即以远低于西方精良设计的成本，快速提供有效的远程打击能力。”加丁纳指出，Ardupilot 是世界上经过最广泛测试的自动驾驶系统之一。乌克兰的小型无人机机群（其中许多衍生自业余设计）很大程度上运行在
研究人员在最后阶段介入，以构建最佳的最终设计。这个获胜的设计将组件分散排列，使得在旋转时没有任何视觉上的重叠。该无人机足够小，可以放在手掌心中，重量仅为 30 克。研究人员上周在澳大利亚悉尼举行的“机器人：科学与系统”（Robotics: Science and Systems）会议上展示了他们的工作。 马修·斯帕克斯（Matthew Sparkes）
FP-5 Flamingo 巡航导弹的模拟图像
开源飞行控制器，例如 Ardupilot。
据乌克兰无人机专家 Serhii Beskrestnov 称，俄罗斯在 Shahed 攻击无人机中也严重依赖商业电子产品。Beskrestnov 在 Telegram 上表示，虽然早期版本通过卫星导航，但新款的“寻求者”（Seeker）版本配备了摄像头和 Raspberry Pi 4 处理器，并搭载人工智能软件以锁定目标。这款由英国制造的 Raspberry Pi 常用于教育和业余计算项目。
Shahed 上的软件尚未被识别，但小型无人机经常使用 Raspberry Pi 搭配名为 YOLO 的开源视觉软件来锁定目标。
乌克兰还部署了由法国和英国公司开发的更传统的风暴阴影（Storm Shadow）巡航导弹，而俄罗斯则拥有自己的高端口径（Kalibr）巡航导弹。
但考虑到商业硬件和开源软件的快速改进，这些成本高昂但性能可以说更优的传统系统在长期内能具备多少竞争力尚不清楚。“随着时间的推移，昂贵的定制军事电子产品和软件可能仅针对最苛刻的需求而开发，”Gardiner 表示。
现在，小国可以制造出几乎与财力雄厚的大国相当的武器，而非国家行为体也可以制造自己的巡航导弹。“成本的剧烈降低，使得许多国家和非国家行为体能够获得此前仅由最富有的国家才拥有的打击能力，”Gardiner 说。 ❚
气候变化
低层云的增加一直为海洋提供遮蔽并冷却地球。但这种反馈目前可能正在逆转，这可能会加速全球变暖。在预测未来气候变化的努力中，云一直是最大的不确定因素，因为它们反射辐射的方式既能加热也能冷却世界。对流层上层的薄卷云并不怎么反射入射的阳光，却会捕捉流出的热量。另一方面，对流层下层的厚层层积云会将阳光反射出地球，这就是为什么地球工程研究人员一直在喷洒微小的海水液滴，试图让它们具有更强的反射率。
气候模型预测，随着世界变暖，形成低云来阻挡阳光的情况将会减少。这可能会触发一个导致进一步变暖的正反馈循环，从而导致低云进一步减少。但卫星数据一直不够一致，无法判断低云是在增加还是减少，特别是在东南太平洋和大西洋，那里倾向于形成最大、最持久的云层。
现在，纽约哥伦比亚大学的 Gregory Cesana 和 Assia Arouf 首次估算了自1979年卫星时代开始以来的低云覆盖情况。这对研究人员基本上将海面温度、风速和大气稳定性的数据与现代卫星仪器测量的低云覆盖率相关联，然后利用这些数据计算了此前几十年卫星测量精度较低时的低云覆盖率。
他们发现，低云覆盖范围一直在扩张，自1979年以来，使地球表面的反射能量增加了 0.32 瓦/平方米。
[[IMG_XXXX]] JIM CORWIN/ALAMY 低层层积云团有助于冷却地球
“如果该趋势如预期般逆转，它可能会‘揭开’变暖的面纱，并进一步加速气候变化”
作为对比，人类引起的气候变化目前正使地球升温约 2.72 瓦/平方米。这意味着低云抵消了全球气温上升的一小部分，尽管很难准确说出抵消了多少。
“我们得到了一个负反馈，因此云实际上在对抗变暖，”Cesana 说。“这与你在使用气候模型的那些理想化实验中得到的结果完全不同。”
研究人员发现，在东太平洋等热带地区，低云覆盖率每十年增加 0.18 百分比（《地球物理研究快报》, doi.org/rgfv）。
这是因为东太平洋的变暖程度低于许多模型的预期，而西太平洋则剧烈升温。结果，东太平洋上空的表面空气保持凉爽，而大气环流将西太平洋日益温暖的空气带到了其上方。由此产生的温度反转防止了温暖、干燥、下沉的空气与低层层积云混合。
“这将有利于低云的形成，或使它们更加稳定，从而延长持续时间，”Cesana 说。
风暴云正在聚集
但科学家预计，东太平洋很快将开始升温，部分原因是由于对硫污染的控制更加严格，而硫污染会形成能冷却地球并影响大气和海洋循环的云层。这将导致温暖的下沉空气使部分这些低云干燥。
这种情况可能已经在发生。今年 3 月，伦敦帝国理工学院的 Paulo Ceppi 及其同事发现，自 2003 年以来，全球低云覆盖率有所下降；而一项 2024 年的研究指出，近期全球变暖的加速可能部分归因于低云出现的一种新兴正反馈效应。
“没有理由认为我们高估了未来气候变化的影响，”Ceppi 表示，“如果非要说有什么问题，由于云层对全球变暖的这种放大效应，我们反而可能略微低估了未来气候变化的后果。”
Cesana 表示，低云覆盖率此前一直在扩张的这一发现实际上可能是个坏消息，因为如果这一趋势如预期般逆转，它可能会“揭开”变暖的掩盖，并进一步加速气候变化。
像目前在东太平洋正在发展的这种导致行星变暖的厄尔尼诺事件会减少低云，“因此我们将能提前体验未来可能发生的情况，”他说道。 ❚
分析 人工智能
为什么人们对中国公司构建的强大人工智能模型的警觉性降低了？Matthew Sparkes 提出了这一疑问
当中国公司 DeepSeek 在 2025 年 1 月发布其开源 R1 模型时，它成为了全球头条新闻。据报道，这款大语言模型 (LLM) 能够与美国公司最强大的某些人工智能相匹敌，而且任何人都可以免费下载。美国科技公司的市值蒸发了万亿美元，美国立法者随即提议禁止在政府设备上使用该模型。
当另一家中国公司 Z.ai 上个月发布 GLM-5.2 时，虽然性能方面有类似的说法，但令人惊讶的是，并没有出现恐慌。美中之间的人工智能军备竞赛似乎出现了一个意想不到的转折。
美国和中国一直竞相开发新的、功能更强大的人工智能模型，并创建训练和运行这些模型所需的芯片和数据中心。近年来，美国政府还对向中国等国家出口芯片引入并加强了出口管制，并时不时地开启或关闭外国用户对最新模型的访问权限。
支持者认为，这项技术可以彻底改变从药物研发到材料科学的所有领域，潜在地为经济注入强心剂。它在战争中用于选择目标和部署武器的日益增加，意味着它也成为了国家安全问题。
然而，美国和中国处理这一问题的方式截然不同。中国公司倾向于发布模型，以便用户可以免费在本地下载并运行，这与大多数美国公司将模型托管在云端、通过付费提供访问权限
[[IMG_XXXX]] 配备 DeepSeek 的机器人正被用于现场检查
并对其内部机制进行保护的方式形成鲜明对比。开源人工智能（包括来自中国的模型）的性能往往不如最昂贵的顶级模型。正如一名英国软件开发人员告诉《新科学家 (杂志)》的那样：“我就用同一个任务测试了一个本地模型 [来自 Z.ai] 和一个云端模型
“如果美国在面对新的美国模型时通过撤回外国访问权限来做出反应，可能会正中中国下怀”
[来自 OpenAI]——本地模型的运行时间长了 30 %，但完全免费。”
在上个月 Z.ai 发布 GLM-5.2 之后不久，人工智能基准测试公司 Artificial Analysis 将其评为市场上最智能的开源人工智能。Z.ai 表示，在一个用于测试人工智能软件工程能力的通用基准测试中，其表现优于 OpenAI 的 GPT-5.5。然而，Artificial Analysis 发现，GLM-5.2 在其智能测试中的表现略逊于 GPT-5.5——这正说明了人工智能行业缺乏统一的性能测试标准。
尽管如此，GLM-5.2 似乎找到了受众。在 OpenRouter 上，它目前排名第五最常用的 LLM；虽然 OpenRouter 仅记录了人工智能使用量的一小部分，但它是少数几个此类数据的公开来源之一。DeepSeek 的最新模型位居第一，使用量是其两倍以上。在前 10 名中，有 7 个是由中国公司构建的人工智能。
GLM-5.2 没有像 DeepSeek 之前的模型那样引起经济冲击波，这或许表明，我们适应“中国在人工智能领域已经追赶上来”这一想法的速度之快，正如它在智能手机和电动汽车等其他技术领域所做的那样。
“传统上，硅谷更具创新性，而中国是一个能够非常有效地规模化的快速追随者，”丹麦哥本哈根大学的 Serge Belongie 表示。他说，激进的开源方面为这种动态增加了一个新维度。
加州大学圣迭戈分校的 Mikhail Belkin 表示，中国的开源模型能力很强，甚至可能更稳定。他说，美国模型随时可能被撤回或修改，而中国模型则可以由任何拥有足够强大服务器的人运行。
一个开放的问题
帝国理工学院的 David Shrier 表示，最终在人工智能领域占据主导地位的公司可能会从一个 60 万亿英镑 (£60 trillion) 的市场中获益，但政府参与这场竞赛同样具有政治和战术上的好处。
如果美国继续通过撤销外国访问权限，来应对性能领先市场的美国新模型，那么它可能会正中中国下怀。
“你是在强迫人们开发自己的生态系统和自己的技术，”牛津大学的 Philip Torr 说道。“你在华为和 Android 身上就看到了这一点：切断它们与谷歌生态系统的联系，它们就会建立自己的生态。”
Shrier 担心，中国可以通过剖析西方模型的操作方式，进一步缩小其自有模型与美国模型之间的性能差距，正如美国公司 Anthropic 曾指责中国公司阿里巴巴那样做的一样。
Belongie 表示，在这场竞赛中，或许能拯救美国大公司的将是商业上的惯性和谨慎。中国的开源模型可能是免费的，可以在笔记本电脑上运行并完成相当不错的工作，但对于大公司来说，使用中国模型感觉就像是一个重大风险。而那些已经提供行业标准软件的、大型且成熟的技术公司，可能会在这一局面中占据有利位置。 ❚
游戏降低男性的痴呆风险 认知训练似乎能帮助男性大脑清除导致斑块的蛋白质
Carissa Wong
一款能将痴呆风险降低 25% 的认知“速度训练”游戏改变了男性体内的 β-淀粉样蛋白（beta-amyloid）水平——这是一种在阿尔茨海默病中会堵塞大脑的蛋白质——但在女性身上没有产生同样效果。 这是脑力训练首次被证明能影响神经退行性标志物的水平，进一步强化了心理练习可以增强大脑健康的证据。 “对于完成了认知速度训练的男性来说，一个预示未来痴呆风险的主要标志物得到了改善，”来自南卡罗来纳州克莱姆森大学（Clemson University）的 Hye Won Chai 说道。她上周在伦敦举行的阿尔茨海默病协会国际会议上展示了这项研究。 这种基于计算机的速度训练包括回忆物体闪现的位置，随着练习的进行，任务会变得越来越难。
海洋生物学
“生物金属”颚 粉碎猎物
某些海蠕虫的颚由一种极其坚硬且轻质的材料组成，被称作“生物金属”，这在工程领域可能具有应用价值。Perinereis cultrifera 是一种身长且布满刚毛的沙蚕。该物种还拥有强有力的颚，使其能够粉碎小型甲壳类动物或其他蠕虫等坚硬的猎物。维也纳工业大学的 Christian Hellmich 及其团队研究这种蠕虫的颚已近十年，这使他们提出这些颚是由一种新型材料制成的。每个颚的分子结构结合了蛋白质和锌等金属离子，使其特性介于较软的生物材料和金属之间。
最近，该团队进行了 3300 次以上的实验，在颚的不同部位制造微小压痕。其硬度在压力下的变化方式遵循了类似于铜和银等金属的典型模式。然而，Hellmich 表示，这种颚还表现出一种金属所不具备的弹性。
[[IMG_STEVE TREWHELLA/ALAMY]]
Perinereis cultrifera 的混合颚具有独特的属性
随后，研究人员开发了一个生物金属的数学模型，展示了它们如何以一种独特的方式应对应变，在这种方式中，微观力源于金属离子排列成类似于某些晶体缺陷的直线（《生物物理评论》/ Biophysics Reviews, doi.org/hcbbwh）。 “刚毛蠕虫的颚极其坚硬且非常轻巧，”俄亥俄州肯特州立大学的 Matthew Lehnert 表示。“从汽车到航空航天，许多行业都在寻找开发坚硬且轻质材料的新方法。答案就在自然界中！” ❚
（此处为另一篇文章的片段）
……效果更好。Chai 的一些同事此前一项为期 20 年的研究表明，与对照组相比，65 岁及以上进行该训练的人被诊断出患有阿尔茨海默病或相关形式痴呆症的可能性降低了 25 per cent。
“这加强了关于心理练习可以提升大脑健康的证据”
在最新研究中，Chai 及其团队招募了另一组来自美国的 53 名 65 岁及以上人士，其中 13 人为男性。约三分之一的参与者被要求在 4.5 个月内，每周完成 2 到 4 小时的速度训练。其余参与者被告知要么花费相同的时间玩游戏，
例如接龙（solitaire）、单词搜索和一种类似于 Connect 4, 的游戏，或者完成另一种大脑训练，在其中他们必须战略性地追踪物体并在任务之间切换。 为了探索速度训练如何降低痴呆风险，团队在训练期开始和结束时收集了所有参与者的血液样本。结果显示，在男性中，速度训练增加了血液中两种形式的 beta-淀粉样蛋白的比例，这表明训练增强了大脑清除 beta-淀粉样蛋白 42 的能力。这种蛋白质在阿尔茨海默病患者的大脑中形成被称为“斑块”的聚集物，从而破坏大脑功能。另外两种训练则没有效果。
一些阿尔茨海默病的治疗方法，例如 lecanemab，旨在帮助清除大脑中的淀粉样蛋白，但它们仅能轻微减缓阿尔茨海默病患者的认知能力下降。伦敦大学学院的 Andrea Castegnaro 表示，临床试验中可见的有限益处可能是由于这些治疗是在病情相对较晚的阶段才采取的，此时已经发生了实质性的大脑损伤。Castegnaro 认为，在痴呆症发作前进行认知训练以减少 beta-淀粉样蛋白的积聚可能会对痴呆症产生更大影响，因为这将在大量大脑损伤发生之前进行。 然而，该训练对研究中女性参与者的淀粉样蛋白水平没有影响。Chai 表示，团队希望在未来的研究中探索速度训练如何使女性受益。 ❚
考古学
公主 曾使用武器
Chris Simms
约 3800 年前的木乃伊揭示，古埃及公主可能使用过弓箭和匕首，并让自己面临严重受伤的风险。在历史上的许多文化中，随葬品中都发现了女性与武器共存的情况。但关于这究竟是象征性的，还是意味着这些女性确实使用过武器，一直存在很多争论。现在，埃及贝尼苏韦大学（Beni-Suef University）的 Zeinab Hashesh 及其团队研究了在埃及中王国时期（约公元前 1850 年至 1700 年）达舒尔（Dahshur）金字塔和陵墓群中发现的六具皇家木乃伊（其中五具为女性）。这些木乃伊中有些与弓箭一同被发现，它们于 19 世纪 90 年代被挖掘出土，并于 2020 年在开罗的埃及博物馆中被重新发现。该团队分析了骨骼，以了解这些皇室成员的生活情况，其中四人被认为是法老 Amenemhat II 的女儿。
一项关键发现是，伊塔（Ita）公主——她的随葬品中有一把精致的金青金匕首，去世时年龄在 28 至 34 岁之间——其前臂骨骼之间具有强有力的连接，且手部肌肉强健。Hashesh 表示，这暗示了习惯性地抓握匕首或权杖等武器。努布-霍特普（Noub-Hotep）公主（年龄在 40 至 44 岁之间）和伊塔韦雷特（Itaweret）公主（年龄在 20 至 34 岁之间）的前臂桡骨均出现增大，这可能是对拉弓时重复性压力的适应。前一名公主与箭矢一同下葬，其掌心右侧第二掌骨还出现了弯曲，且手指肌肉的附着点得到了加强。这些迹象暗示了持弓所需的持续机械负荷，并表明存在“弓箭手抓握”（archer’s grip）（《环境考古学前沿》，doi.org/rf2s）。
Hashesh 说：“为了形成在努布-霍特普身上观察到的弓箭手抓握以及手骨的结构性弯曲，她们一定从很小的时候就开始接受弓箭和武术训练。”澳大利亚格里菲斯大学（Griffith University）的 Michelle Langley 表示，这项研究让我们真正地洞察了这些公主的生活。“皇室女性并非只是坐在宫殿里或跟随男性成员在后，而是过着积极且熟练的生活。她们接受了非常实用的军事和狩猎艺术训练，正如我们想象她们的父亲和兄弟所接受的那样，”她说道。
骨骼还揭示了受伤的情况十分普遍。例如，伊塔韦雷特公主曾经历过肋骨骨折和足部骨折，Hashesh 表示这可能是由事故或剧烈打击造成的。“这告诉我们她们活跃在外界，或许参与了某些高冲击力的活动，在那里跌倒和打击是真实的危险，”她说道。但英国南安普敦大学（University of Southampton）的 Sonia Zakrzewski 认为，其他活动也可能导致手臂和手骨产生类似的改变，例如杂耍或使用镰刀。 ❚
动物学
体味的猴子是科学界的新发现
James Woodford
DANIEL ROSENGREN
在刚果民主共和国的一个偏远地区发现的一种拥有独特面具般面孔的猴子，已被宣布为一个新物种。当地人将其称为 likweli，其科学名称被定为 Colobus congoensis。
佛罗里达大西洋大学的 Kate Detwiler 表示，likweli 最引人注目的特征之一是它的面部外观。口周和鼻下的浅色皮肤与任何其他非洲疣猴（colobus）物种都不同。她说，与其他疣猴一样，likweli 还拥有一种难以言表的独特体味。
科学家们最早在 2008 年注意到该物种。当时一个在洛马米河（Lomami river）岸边（即现在的洛马米国家公园）进行调查的团队拍摄了一张照片，照片中显示了林冠层中一只未知猴子的一部分。
随后，在 2018 年 11 月，另一个小组再次发现了这种猴子，其体长约 1.3 米，体重约 7 公斤。在 2018 年至 2022 年之间，共有 114 次对该新物种的记录观察，其中 25 次是通过发声识别的。
Colobus congoensis 拥有独特的“面具” 和橙色嘴唇
2021 年，几只被猎人杀死的猴子被没收并移交给研究人员。详细的形态学和遗传学分析确认，它们确实是一个完全独立的物种（PLOS One, doi.org/hcbp8q）。遗传学测试及其发声记录也进一步证明了其独特性。
“遗传分析显示，likweli 是一个深度分化的谱系，大约在 4 到 5 million 年前与其最亲近的已知亲缘物种 Colobus satanas 分离，”Detwiler 说道。
likweli 与 C. satanas 之间隔着 1200 多公里以及几条主要的河流屏障。大多数该属的其他成员栖息地超过 60,000 平方公里，而 likweli 仅已知存在于 1700 平方公里的雨林中。由于盗猎风险以及该猴子数量少且分布范围小，该团队建议将该物种列为濒危物种。 ❚
癌症
Alice Klein
MEHAU KULYK/SCIENCE PHOTO LIBRARY
在一次临床试验中，四名患有传统上不可治愈的脑癌儿童在接受了一项实验性免疫增强细胞疗法数年后仍然存活。其中三名儿童甚至没有显示出疾病迹象。
“这些孩子能够长大——这简直太棒了，”华盛顿特区儿童国家医院（Children’s National Hospital）的 Gene Hwang 说道。
这项名为肿瘤相关抗原（TAA）T细胞疗法的实验性治疗，被用于 33 名儿童和年轻人，他们要么是新诊断出弥漫性内在桥脑胶质瘤（DIPG，一种极具侵袭性的脑癌），要么是患有对标准治疗无反应的其他脑肿瘤。团队成员、同样就职于儿童国家医院的 Catherine Bollard 表示，试验重点关注这些肿瘤类型，是因为“它们普遍致命，患者已无其他选择”。
患有 DIPG 的儿童通常生存期不足一年，但在接受 TAA T-cell 疗法后，一名患此病的治疗儿童在两年多后依然存活。
在其他类型的脑肿瘤参与者中，三名患者对该疗法反应极其良好。他们患有侵袭性的复发性胶质母细胞瘤、星形细胞母细胞瘤或髓质母细胞瘤，此前曾接受过多达 17 轮化疗和放疗等治疗，但均告失败。
自接受 TAA T-cell 疗法以来，这三名儿童在两年至五年后依然存活，且没有疾病迹象（《自然-医学》Nature Medicine, doi.org/rfzx）。
“我仍与其中一个家庭保持联系，他们对自己孩子今天能留在身边感到难以置信地感激，”Bollard 说道。
此次试验规模较小，且没有设置对照组以将该疗法与标准治疗进行比较，但 Bollard 表示，“我们非常兴奋，因为虽然这仅是一项 I 期安全性研究，但似乎已经出现了疗效信号”。她指出，目前尚不清楚为什么该治疗对某些儿童有效而对另一些则无效。
“还没有人跳起来说‘这就是最终答案’，但这令人鼓舞，且在我们理解如何利用细胞疗法攻击脑肿瘤方面又向前迈了一步，”澳大利亚昆士兰儿童医院（Queensland Children’s Hospital）的 Tim Hassall 说道。
Bollard 解释说，该疗法包括抽取患者血液样本，收集名为 T 细胞的免疫细胞，并在实验室中对其进行“训练”，使其能够靶向儿科脑肿瘤中常见的三个蛋白质标记（即抗原）。具体操作是通过将 T 细胞暴露在表达这些抗原的其他细胞中，然后选择性地增殖能够识别这些抗原的 T 细胞。随后，这些增殖后的 T 细胞通过静脉注射回人体，从而使患者自身的免疫系统能更有效地对抗癌症。
在试验中，大多数参与者对该疗法耐受良好，最常见的副作用为疲劳和头痛。两人出现了肿瘤肿胀，但 Bollard 表示，这可能是因为他们原本的肿瘤体积就较大。
“在过去的 20 年左右，我们在提高这些儿科脑肿瘤生存率方面几乎没有取得进展，因此能开辟一个完全不同的治疗领域令人兴奋，”Hassall 说道。 ❚
健康
清除体内的微塑料
Helen Thomson
根据一项旨在清除微塑料的补充剂首次人体试验表明，一种后生元（postbiotic）可能会限制我们对微塑料的吸收。它利用死菌的粗糙表面来吸引微塑料，从而防止其进入细胞。微塑料的长度小于 5 毫米，在环境中无处不在，并且在人体各处均被检测到，尽管目前尚不清楚它们是否会导致任何健康问题。
佛罗里达州生物制药公司 Quorum Innovations 的联合创始人 Eva Berkes 及其团队通过培养发酵柠檬乳杆菌（Limosilactobacillus fermentum），用热力将其杀死并收集其细胞壁，创造了这种名为 Qi601 的后生元。
随后，他们将类人肠道细胞暴露在纳米塑料（小于 0.001 毫米）中，并分别观察加入和不加入后生元的情况。在没有 Qi601 的情况下，纳米塑料在细胞内及其表面积聚。但当加入 Qi601 后，细胞内部或表面的可见纳米塑料显著减少，这表明后生元在纳米塑料被吸收之前将其清除。
该团队还要求参与者咀嚼商业口香糖（这会在唾液中释放大量微塑料颗粒），直到收集到 10 毫升唾液。研究人员随后重复了该实验，但在咀嚼 5 秒后，在参与者口中放入了 10 毫了克 Qi601 粉末。对一名参与者的唾液分析显示，仅咀嚼口香糖后有 2152 个自由漂浮的塑料颗粒，而加入 Qi601 后仅为 185 个（bioRxiv, doi.org/rf3k）。
“我们的结果首次证明了微塑料可以在[人体]中被微塑料缓解剂结合，”Berkes 说道。 ❚
玛雅天文学家姓名被破译 玛雅建筑墙上的象形文字记录了关于行星轨道的计算
James Woodford
一名古代玛雅天文学家兼数学家首次被确认，及其在约 1200 年前进行的复杂计算，这些计算预测了火星和金星的轨道周期。
“这是首次通过个人姓名直接提及一位玛雅祖先天文学家兼数学家，”马萨诸塞理工学院的 Franco Rossi 说道。
玛雅文明在约公元前 2000 年至公元 1697. 年之间在中美洲繁荣发展。他们拥有先进的天文学和数学知识，但在西班牙传教士大规模焚书后，许多知识丢失了。
自 2010, 年起，在危地马拉 Xultun 遗址的挖掘中，人们在一座小型石砌建筑内部发现了天文学和数学铭文。在该建筑的东墙和东北墙上约有 50 篇文本，科学家认为这些是玛雅数学家在绘制和预测时制作的“草稿”。
动物行为
控制裸鼹鼠群落
有一种气味能统治所有成员——而我们现在知道了那是由于什么。一系列实验表明，裸鼹鼠群落中的蚁后释放的一种单一分子，能够阻止群落中所有其他雌性进行繁殖。 “如果你是一只鼹鼠，这就是一种超级避孕药，”柏林马克斯·德尔布吕克中心的 Gary Lewin 说道。 裸鼹鼠 (Heterocephalus glaber) 拥有类似于蜜蜂和蚂蚁的社会结构，群落由士兵和工蚁组成，每只群落由一名蚁后统治。
PROYECTO REGIONAL ARQUEOLÓGICO SAN BARTOLO-XULTUN; PRASBX
这些铭文是在危地马拉 Xultun 的这个房间内发现的
天体相对于地球以及彼此之间的运行周期。 Rossi 及其同事费力地破译了其中一幅壁画，被命名为 Text 19。在壁画底部是一个名为 Sak Tahn Waax 的名字，翻译为“白胸狐”，据信
群落中只有蚁后能够繁殖，但她如何维持长期的统治——Lewin 团队中最年长的蚁后已 39 岁——此前并不明确。 “之前的理论认为，蚁后比其他动物体型更大且更具攻击性，通过推搡来发挥其统治地位，”Lewin 说。“但我们一直觉得这种解释并不太令人满意。” 因此，团队成员 Mohammed Khallaf（同样来自马克斯·德尔布吕克中心）提出要鉴定鼹鼠的“香气组合”——即它们周围空气中产生气味的分子。通过对比数百只动物的气味发现，只有蚁后能产生一种名为肉豆蔻酸异丙酯（isopropyl myristate）的分子。
被认为是该公式的作者。 Text 19 由 11 个象形文字组成。在推断出其含义之前，必须对其进行扫描、拍摄，并在不同光照角度下放大，并与后期的天文数学著作进行对比（Antiquity, doi.org/rfzp）。 虽然在玛雅各城市中都能发现类似的数学和天文学专业知识，但提及 Sak Tahn Waax（研究人员认为可能为男性）的情况是独一无二的。 “无论这是一个抄写员在自己的计算结果上签名，还是将这项智力成果归功于他人，我们都得到了一个公式及其创造者的名字，这证明了这类智力贡献对于古典玛雅人的重要性，”Rossi 说道。 他表示，Text 19 中展示的历法系统使用了与时间周期相关的数学。这些时间周期取自
NEIL BROMHALL/SHUTTERSTOCK
“它产生于生殖器官，基本上是繁殖期雌性的阴道，”Lewin 说道。 当研究团队每天向含有雄性和
一个 260 天的历法，一个 365 天的太阳历，一个 584 天的近似金星会合周期（指该行星回到相对于地球和太阳的相同位置的时间），以及一个 780 天的近似火星会合周期。该公式的总长度为五个金星会合周期，即 2920 天，而
“ 我们认为其目的是为了 展示这两颗行星 与人类时间计数之间的关系”
Text 19 最可能指的日期是儒略历 781 年 11 月 7 日。 至于这个公式具体是如何应用的尚不清楚。 “我们认为，它的目的是以简洁且有意义的方式展示这两颗行星与人类时间计数之间的关系，进而可应用于政治仪式、预测天文学以及对季节性的理解，”Rossi 说道。 ❚
蚁后是唯一被允许繁殖的雌性裸鼹鼠
雌性配对，没有雌性怀孕。而如果没有该物质，几乎所有雌性都怀孕了 (Nature, doi.org/rfzq)。接着，研究团队从一个群体中移走了一只蜂王，并每天涂抹肉豆蔻酸异丙酯。在进行此操作的三个月期间，没有出现继承权的争斗，也没有雌性开始繁殖。当研究团队停止涂抹该化学物质时，高等级的雌性在一周内开始争斗。大约三周后，其中一只怀孕了：成为了新的蜂王。 ❚
Jacob Aron 是《新科学家 (杂志)》的高级编辑， 专注于数学、物理 及技术方面的写作
Jacob 的一周
我正在阅读 金·斯坦利·罗宾逊 (Kim Stanley Robinson) 的 《未来部》(The Ministry for the Future)，在近期的 酷暑中阅读这部作品有些吃力
我正在玩 《Selaco》，一款继承了《毁灭战士》(Doom) 和《半条命》(Half-Life) 伟大传统的 精彩第一人称射击游戏
我正在研究 一篇关于遥远未来的特写报道，这也是我 阅读上述书籍的原因！
狡黠的数学 一种无需给出答案即可解决问题的方法在 100 年前曾引发数学家们的激烈争论，但 Jacob Aron 发现，它现在已成为数学中的常见部分
一名数学家打开办公室的门，发现起了一小场火。她没有惊慌，环顾房间，发现了一个灭火器。“啊，解法存在！”她说道，随后关上门，继续她的一天。仅仅知道灭火是可能的，就足以证明这个问题可以被解决——为什么还要费力去实际操作呢？这个老笑话总结了许多现代数学的研究方式，这要归功于一种狡黠的解题策略：非构造性证明。
这是一个很难理解的微妙概念，所以这里举一个基本不涉及数学的例子。假设房间里有 367 个人——其中两人生日相同的概率是多少？答案是 100 ％，因为（假设我们考虑闰年）只有 366 个可能的生日，而每个人都必须有一个生日，所以至少有两人必须在同一天生日。
这就是数学家所说的“鸽巢原理”的一个例子——人是鸽子，生日是鸽巢——这是处理非构造性证明的一种经典方法。我们知道一定有两个人生日相同，即使我们完全不知道在 367 个人中，具体是谁。
传统上，证明过程与此恰恰相反。如果你证明了某件事，通常意味着你已经掌握了一个具体的数学对象，并将其展示给所有人看。这一切在 19 世纪开始改变，非构造性证明成为了数学家武器库中一个更强大、更受欢迎的工具。这种新数学方法的先驱是戴维·希尔伯特 (David Hilbert)，他是那个时代最伟大的数学家之一，且在某些人眼中，他是个麻烦制造者。
“希尔伯特认为这很荒谬，将这些限制比作‘禁止拳击手使用拳头’”
希尔伯特研究的问题非常复杂，需要先做一些铺垫。让我们从思考一个正方形开始。你可以将正方形旋转 90 度，它看起来依然一样——你可能熟悉这个概念，它被称为旋转对称。另一种描述方式是，正方形在 90 度旋转下是“不变的”。
希尔伯特对“不变性”感兴趣，但不是针对正方形这类几何对象，而是针对方程这类代数对象。对于一类给定的代数对象，数学家们意识到本质上存在无限个不变项。那么问题就变成了：你实际上需要多少个？你能否从几个关键的不变项开始，并利用它们构建出任何你想要的另一个不变项？
希尔伯特并不是第一个尝试为不变项确定“生成集”的人——另一位
数学证明 提供了一个逻辑论据， 证明某个理论是正确的
LUCIDIO STUDIO, INC./GETTY IMAGES
数学家保罗·戈丹 (Paul Gordan) 曾将其整个职业生涯都用于研究它。戈丹为少数几个对象发现了有限生成集，但他的证明过程杂乱且复杂。因此，当希尔伯特 (Hilbert) 在 1888 年出现并证明这对于更大类别的代数对象同样成立时，他感到十分震惊——而希尔伯特实际上并没有具体说明这些生成集的构成。希尔伯特是通过首先假设存在一个无法由生成集产生的不变量，然后证明这将导致以一种不符合希尔伯特所操作的代数规则的方式，产生无穷无尽的更多不变量——这便产生了逻辑矛盾。那么，解决这一矛盾的唯一方法就是：生成集必须始终存在。
数学分歧
戈丹对这种非构造性证明的最初反应是否定的。“这不是数学，这是神学，”他说。他惊骇于希尔伯特竟然要求他在没有提供生成集的情况下就相信其存在——这怎么能算作一个答案呢？不过，戈丹后来接受了希尔伯特的思维方式，并表示
那么“神学确实有其优势”。 希尔伯特的战斗尚未结束。正如他年轻时曾是一个挑战戈登的后起之秀，后来又出现了一个更年轻的挑战者——L.E.J. 布劳威尔。希尔伯特花了整整几十年时间构建形式主义的数学哲学。这种观点基本上认为，数学是一种以逻辑方式操纵符号以产生证明的游戏，而无需过于关心这些符号可能对应的现实世界或数学对象。对于形式主义者来说，非构造性证明仅仅是赢得这场游戏的多种方式之一。 布劳威尔痛恨这个想法。他的哲学是直觉主义，认为数学是人类心智的创造。他拒绝将符号操纵视为数学的底层活动，仅将其视为数学家之间传递思想的一种方式。在这种观点中，非构造性证明等同于作弊——一个数学对象若要真实存在，你必须能够在脑海中将其构造出来。 这两种哲学真正发生碰撞的地方在于一个被称为“排中律”的概念。这是一个古老的逻辑原则，规定对于每一个逻辑命题，要么该命题为真，要么其否定为真。换句话说，如果我说“希尔伯特是一只猫”，那么要么这句话必须是真的，要么希尔伯特不是一只猫（为了避免疑问，显然是后者）。 这看起来可能显而易见，但事实证明它是一个有用的数学工具。在希尔伯特 1888 年的证明中，他假设“并非所有不变性都可以由一个有限生成集产生”，并发现了一个矛盾，从而证明该命题为假。根据排中律，“所有不变性都可以由一个有限生成集产生”必然为真，即便无需展示如何构造这样一个集合。
[[IMG_ULLSTEIN BILD VIA GETTY IMAGES]]
布劳威尔的反对意见在于，像希尔伯特那样将排中律应用于无限对象集。对于有限集，他并不反对使用该定律，因为原则上你可以检查集合中的每个对象，并让自己确信它们是否具有某种属性。但对于无限集，这是无法实现的。 希尔伯特认为这简直荒谬，将对排中律的限制比作“禁止拳击手使用拳头”。而布劳威尔则将希尔伯特称为“我的敌人”。这是一个麻烦，因为两人都在《数学年报》（Mathematische Annalen）工作，该杂志在当时和现在都是数学领域最重要的期刊之一。希尔伯特与阿尔伯特·爱因斯坦等三人共同担任编辑，而布劳威尔则在编辑委员会中。希尔伯特如此
大卫·希尔伯特在构建形式主义数学哲学中起到了关键作用
“形式主义者将数学视为一种以逻辑方式操纵符号以产生证明的游戏”
对布劳威尔（Brouwer）在期刊中影响力如此之大感到愤怒，以至于在 1928, 年，他解雇了整个编辑委员会，仅仅是为了除掉他。作为回应，爱因斯坦也辞去了他的职务，并问道：“数学家们之间这种青蛙与老鼠的斗争是怎么回事？”
从实际情况来看，爱因斯坦将这场争论斥为无意义是对的。如今，极少有数学家关注某种明确的哲学，绝大多数人都很乐于将非构造性证明作为一种有用的工具。你可以说这意味着希尔伯特（Hilbert）获胜了，而且在被《数学年刊》（Mathematische Annalen）解雇后，布劳威尔确实变成了一个日益孤立且无关紧要的人物。但正如我之前写过的，希尔伯特的形式主义很快就被库尔特·哥德尔（Kurt Gödel）给予了致命一击，哥德尔的不完备定理表明，操纵符号的游戏永远无法完全一致。哥德尔并不是一个直觉主义者——事实上，他的完备定理（不完备定理的前身）依赖于排中律——但在他自己与希尔伯特的斗争中，他确实从布劳威尔那里得到了启发。
哥德尔和布劳威尔的思想后来在计算机科学中变得至关重要，影响了艾伦·图灵（Alan Turing）的工作以及关于哪些问题是可计算的问题。如今，随着数学家转向 人工智能 和形式证明验证（在这种验证中，证明的每一步都必须被转化为机器可读形式以验证其真实性），这些想法正重新流行起来。这反过来可能会导致有一天出现一个被验证为逻辑真实的非构造性证明，但数学家们却无法完全理解，因为它是由一个无法向人类思维解释的 人工智能 创建的。如果那样发生，布劳威尔将笑到最后。 ❚
Chanda Prescod-Weinstein 是新罕布什尔大学的 物理学与天文学副教授。 她是《无序宇宙》 (The Disordered Cosmos) 的作者。 她的最新著作是《时空的边缘： 粒子、诗歌与宇宙梦幻舞曲》 (The Edge of Space-Time: Particles, poetry, and the cosmic dream boogie)
Chanda 的一周
我正在阅读 Stephanie Wambugu 的《孤独的人群》 (Lonely Crowds) 和 Maria Adelmann 的 《兼职教师》(The Adjunct)， 这两本书都以有趣的方式探讨了校园生活
我正在观看 我非常喜欢《上帝是否在》(Is God Is)， 并且很享受观看《超女》(Supergirl)
我正在研究 我一直在为一门量子场论课程 挑选教科书
今年 10 月，我将在伦敦举办的 新科学家 (杂志) Live 活动上，探讨暗物质的奇妙之处——这种不可见的物质主导着星系。当我进行此类演讲时，我会强调暗物质与可见物质（即构成我们的物质）之间的区别。为了突出这一点，我强调人类是夸克和电子的集合——宇宙中大多数事物皆然。
用这种方式来描述人类或许很有趣，因为我们倾向于认为人类在本质上是生物性的。如果你问一名生理学家人类是由什么组成的，他们可能会说：“我们 60% 是水，大约 20% 是碳，再加上少量的其他物质。”换句话说，我们主要由氢和氧组成。
从技术上讲这是正确的，但生理学家的视角与物理学家有所不同，后者的研究深入到了原子层面以下。以最简单的原子——氢为例。在最基本的形式中，氢由原子核内的一个质子和一个绕轨道运行的电子组成。氢也可以包含一个或多个中子。与此同时，氧的原子核内有 8 个质子，最多 8 个电子，以及多达 20 个中子。每一种原子元素都是这些亚原子粒子的某种组合，因此你
“ 我们称它们为‘虚’粒子，是因为它们的寿命如此短暂，以至于它们就像根本不存在一样”
可能会认为粒子物理学家会回答：“人类是由质子、中子和电子组成的。”但其中一项与其他的不同：电子是基本的、不可分割的粒子。而质子和中子是复合粒子。一个质子由两个上夸克和一个下夸克组成，而中子则相反，由两个
PHOTOJUNCTION/ALAMY
夸克从不孤单，一种被称为胶子的特殊粒子确保它们不会漂离
下夸克和一个上夸克组成。夸克与电子一样，不能被分解成更小的东西。
所以，回到人类是由什么组成的问题，我经常告诉人们我们是夸克和电子的集合。在我为新书《时空的边缘》（The Edge of Space-Time）进行巡回宣传时，我开始越来越多地思考这是否是对情况的公正描述。还有另一种粒子我也应该将其纳入——嗯，也许吧。
复杂之处部分源于夸克是如何结合在一起的。独特的是，夸克永远不会单独存在。它们总是与其他夸克组合在一起。它们最稳定的组合是我们熟知的质子和中子这种三夸克组合。还有许多其他的三夸克复合粒子，以及双夸克和五夸克（five-quark）组合，但所有这些都是不稳定且短寿的。
但你永远看不到单个的夸克，这是因为强力的运作方式。
将夸克固定在原位的强核力非常强大，以至于如果我们试图将一个夸克从质子中拉出来，所涉及的能量将足以创造另一个夸克和一个反夸克，而这
实际上是一个夸克的反物质版本。质量相同，电荷相反。最终，夸克仍然被束缚在某些东西上，根本无法逃逸。这是因为另一种粒子：胶子（gluons）。
是的，我们有将夸克黏在一起的粒子，叫做“胶子”！所以你可能会认为，我真的应该告诉人们人类是由电子、夸克和胶子组成的。强相互作用之所以发生，是因为夸克通过胶子进行相互作用，因此将它们列入“成分表”似乎是有道理的。
但这里有个陷阱：胶子与夸克和电子有点不同，因为它们不是“真实”的。这不是笔误。胶子在维持物质结合方面发挥着重要的物理作用，但它们也是彻头彻尾的怪胎：它们没有实质性的物理存在。事实上，我们称它们为“虚”粒子，因为它们的寿命极其短暂，以至于就像根本不存在一样。
虚光子也会出现在原子中，作为电磁相互作用的一部分，而我绝不准备声称人类是由光粒子组成的。因此，当我解释我们是电子和夸克的集合时，我省略了胶子。
胶子的奇异之处也凸显了为什么“粒子”其实并不是描述原子内部发生情况的一个好方法。粒子的概念会让人联想到一个小台球。但当我们试图想象某种几乎不存在的东西时，这种视觉比喻并不怎么适用。因此，我可能会坚持说我们是由夸克和电子组成的非凡集合，但我想我们将在十月份实时地看到，我是否改变了主意，决定加入那些难以捉摸却威力巨大的胶子。 ❚
要了解更多关于新科学家 (杂志) Live 的信息，请访问 newscientist.com/nslmag
雕塑家 Jason deCaires Taylor
气候与健康活动家 Gladys Bartlett 已被塑造成一座雕塑——《所罗门塞壬》（The Solomon Siren）。该作品最近被安置在她现在已被淹没的旧居：所罗门群岛的 Kale 岛上。
雕塑家 Jason deCaires Taylor 将该作品作为其在全球范围内创作的《塞壬》（Sirens）系列装置的一部分，旨在突出海水变暖、污水污染以及微塑料的存在。
当洪水导致无法生存时，Bartlett 和她的家人不得不撤离到其中一个主岛上。“那时，[这座岛]还是陆地——绿色、充满活力、生机勃勃，”Bartlett 在伴随雕塑安装的影片中说道。“Kale 岛成为了所罗门群岛中首批有记录的因海平面上升而消失的岛屿之一。”
该雕塑由一棵海洋级不锈钢树组成，Bartlett 的等身像倚靠在树上。该艺术品还使用了生物炭和 pH 中性水泥。令人心碎的是，随着潮汐的涨落，它在波浪翻滚中时隐时现。
雕塑中刻有记录 Kale 岛淹没历史里程碑的文字，以及预测到 2046. 年海平面最高将上升 20 厘米的预估。但正如 Taylor 所说，这座雕塑并非旨在充当科学测量仪器，而是作为陆地与海洋之间关系变化的“象征性表达”。
“所发生的一切不仅是对我们的警告，更是对全世界的警告，”Bartlett 说道。 ❚
虽然近期的热浪让我们不得不躲在阴影中，但一本引人入胜的书揭示了阳光对健康的益处——大卫·罗布森（David Robson）发现，关键在于适度。
书籍 《为阳光辩护》（In Defense of Sunlight） 罗安·雅各布森 (Rowan Jacobsen) 著 Scribner 出版社
大约一百年前，医生们积极鼓励日光浴。第一次世界大战的外科医生注意到，士兵的伤口在暴露于太阳射线后愈合得快得多；关节炎患者感到疼痛减轻，而支气管炎和肺部感染患者发现咳嗽有所缓解。高血压患者的血压有所下降。《柳叶刀》（The Lancet）甚至将其宣布为“自然界维持和获得健康最伟大的辅助手段之一”，并呼吁增加公共场所脱衣的空间。
“乍一看，一个群体刻意实践裸体，特别是受到市政部门的鼓励，在普通人看来有些荒谬，”一篇 1932 年的文章写道。“但人们发现阳光照射在皮肤上对健康有益，这在一定程度上消除了这些偏见……只要这样做是为了健康，并且……男女分开。”
今天，我们谨慎得多。我们被告知要遮盖身体并涂抹大量防晒霜，即使在冬天也要保护自己免受有害紫外线的侵害。但这种建议是否走得太远了？这就是记者罗安·雅各布森在其迷人的新书《为阳光辩护：关于日晒的惊人科学》（In Defense of Sunlight: The surprising science of sun exposure）中所提出的论点。他说，他是受到了日晒能触发提升情绪的内啡肽这一发现的启发。
“像大多数人一样，我从小就被灌输：太阳是……皮肤癌的主要原因，而唯一可以允许接触我未受保护皮肤的射线量就是零，”他写道。“但如果我们天生倾向于寻求阳光，那么一定是有原因的。”
尽管这个前提略显单薄（大脑的快感系统可能会诱导我们寻求许多对身体有害的事物，包括药物、酒精和糖），但雅各布森构建了一个非常有说服力的论点，他记录了适度日晒使我们身体恢复活力的许多惊人方式。
“研究发现，暴露于紫外线会释放皮肤中的一氧化氮，从而降低血压”
阳光最著名的益处曾被认为主要集中在身体产生维生素 D 的作用上。相关性研究表明，该化学物质的高水平似乎能降低许多健康问题的风险，包括肥胖、糖尿病、骨质疏松症、心脏病发作、中风、抑郁症、呼吸道感染和结直肠癌。然而，雅各布森指出，除非某人严重缺乏，否则服用维生素补充剂在很大程度上未能对这些问题产生影响。这留下了一个耐人寻味的可能性：人们自然维生素 D 水平的测量结果，实际上仅仅是其[[SOURCE_CLEANUP_NOTE: 缺失文本]]的替代指标。
另外三本关于阳光在生活中扮演重要角色的优秀书籍
《生命时长：身体时钟的新科学，以及它如何彻底改变你的睡眠与健康》（Life Time: The new science of the body clock, and how it can revolutionize your sleep and health） 罗素·福斯特 (Russell Foster) 著
我们中的许多人将白昼延长至深夜。罗素·福斯特关于人体昼夜节律的指南揭示了为什么这样做是个糟糕的主意。他利用自己的研究，敦促我们利用这些节律来改善睡眠、情绪和注意力。
《皮肤的非凡生命：一次关于我们表层的亲密旅程》（The Remarkable Life of the Skin: An intimate journey across our surface） 蒙蒂·莱曼 (Monty Lyman) 著
皮肤是我们最大、生长最快且最不被了解的器官。当然，它也是太阳射线的主要接收者。医生兼研究员蒙蒂·莱曼探讨了该器官在我们健康中所扮演的重要角色。
《追逐太阳：阳光的新科学及其如何塑造我们的身体与心灵》（Chasing the Sun: The new science of sunlight and how it shapes our bodies and minds） 琳达·格德斯 (Linda Geddes) 著
前《新科学家 (杂志)》员工琳达·格德斯深入探讨了历史上和不同文化中太阳在生活中的作用——以及当我们把如此多的时间花在室内时，究竟失去了什么。
整体的阳光照射，此前一直通过多种其他机制保护着身体。
其中一条可能的路径是 nitric oxide（一氧化氮），一种能使我们血管扩张的化学物质。科学家们最近开始得出结论，一氧化氮缺乏是导致高血压的主要驱动因素，而且——相当令人惊叹地——一系列研究发现，暴露在紫外线下会在我们的皮肤中释放这种微小的化学物质，进而降低血压。
Jacobsen 认为，这一发现可能为地中海国家的人们为何往往身体如此健康提供了另一个理由。他指出，该地区著名饮食中的叶菜类蔬菜含有大量硝酸盐，而这些地区充足的阳光有助于人体将其转化为一氧化氮，从而放松心血管系统。仅仅采用地中海饮食
已被证明可以降低血压，但不如增加阳光照射的效果显著，雅各布森（Jacobsen）写道：“正是两者的结合起到了作用，且应成为真正地中海饮食的基础。”在其他方面，他指出有证据表明，适度的阳光照射会释放皮肤中的化学物质，有助于抑制过度活跃的免疫系统，这或许可以解释为什么阳光似乎能缓解多发性硬化症（独立于维生素 D 的产生）和 1 型糖尿病等疾病。甚至有证据表明，阳光中的红外波长能够深入渗透人体，刺激我们的线粒体，从而改善我们的代谢。
当然，笼罩在这一切之上的阴云是随阳光照射而增加的皮肤癌风险。对此，雅各布森指出，大多数皮肤癌
是基底细胞癌和鳞状细胞癌，这些癌症通常不会扩散到身体其他部位，且通常可以通过手术治疗。黑色素瘤更为危险，但相对罕见，且与其他癌症相比，其生存率仍然很高。
[[IMG_XXXX]] 遮阳海滨小屋帮助我们避免过度接触好事：阳光
“是的，阳光是皮肤癌中主要的、可改变的风险因素，但心血管疾病导致的死亡人数是
皮肤癌死亡人数的一百倍，”雅各布森写道。“我认为我们需要找到风险与收益的比例。”为了支持这一点，他提到了一项针对 30,000 名瑞典女性的有影响力的研究，该研究发现，阳光照射与更低的死亡风险相关：在 20 年的时间里，“避日者”的死亡可能性约为“日晒爱好者”的两倍。
显然，我们不应将这种重新发现的对“日光疗法”的推崇推向极端；《柳叶刀》（The Lancet）不太可能在短期内重启其倡导裸体日光浴的运动。风险的平衡将取决于大量因素，包括肤色、季节和纬度，这使得很难针对最佳阳光照射水平给出普适性的建议。
最终，雅各布森的建议与英国卫生服务部门的建议非常接近。他建议，充分利用紫外线成分较低的早晨和傍晚，但在一天中最热的时段要遮盖皮肤并寻找阴凉处。对于在风险最高时段之外的日常防晒霜使用，他的态度有些矛盾，但认同只要存在晒伤的可能性，使用防晒霜就是明智的。他说，即使是短时间的照射，可能也足以获得益处。
尽管这本书描述了诸多前沿研究，且发人深省，但其传达的信息却极其简单：“接触阳光。适量。走到户外。”是时候让我们大家都“见光”了。 ❚
JUSTIN TALLIS/AFP VIA GETTY IMAGES
大卫·罗布森（David Robson）是一位专注于人类大脑、身体和行为的科学作家。他的最新著作是《连接法则：13 个将改变你生活的社交策略》（The Laws of Connection: 13 social strategies that will transform your life）。
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安尼什·卡普尔（Anish Kapoor）在伦敦海沃德美术馆（Hayward Gallery）举办的大型回顾展，轮番呈现出令人惊叹、心生敬畏以及恐惧的感受。展览将持续至 18 October，它唤起了宗教主题，同时也提出了关于现实与时空的问题。以《贫民窟之门》（Gate of the Ghetto）中的摩利亚山（Mount Moriah）为例，该山以圣经中上帝要求亚伯拉罕献祭其子的山峦命名。卡普尔将这座巨大的山悬挂在天花板上，将其浸染在闪亮的红色颜料中，看起来像血液和裸露的肌肉——或者是岩浆？另一个房间则展出了卡普尔的《哈·马孔》（Ha Makom）（见上图），这是一个巨大的、岩石般的深红色景观，中心有一个黑色的矩形门户。据卡普尔所述，该作品汲取了神圣存在的影响，并受到了在澳大利亚访问乌鲁鲁（Uluru）的启发。它是少数几件使用了 Vantablack 的作品之一，这是一种由碳纳米管制成的奇迹颜料，能吸收 99.96 per cent 的光线。卡普尔利用它来创造虚空以及看似时空中的裂缝，让观众得以品味物理学家在试图理清现实结构时可能产生的一种体验。
DAVE MORGAN. COURTESY OF THE HAYWARD GALLERY AND THE ARTIST. © ANISH KAPOOR
额外价值 本周推荐两本绝佳读物：《升华》(Sublimation)，一部紧张刺激的惊悚小说，设定在一个跨越国际边界会将你分裂成两个相同副本的世界；以及《在太空被苔藓覆盖》(Moss’d in Space)，一部超级温馨且幽默的科幻小说。Emily H. Wilson 对这两本书都非常满意。
Emily H. Wilson 是《苏美尔人》(Sumerians) 系列（包括《伊南娜》(Inanna)、《吉尔伽美什》(Gilgamesh) 和《宁舒巴尔》(Ninshubar)，均由 Titan 出版）的作者，目前正在创作她的第一部科幻小说。她曾是《新科学家 (杂志)》的编辑，您可以在 Instagram 上关注她 @emilyhwilson1。
书籍 《升华》(Sublimation) Isabel J. Kim Picador
《在太空被苔藓覆盖》(Moss’d in Space) Rebecca Thorne Tor
Emily 推荐...
书籍 《燃烧时刻》(Time to Burn) Ellery Lloyd Macmillan 本月另一部新书，讲述了回到伦敦大轰炸时期的旅程。这部情节曲折的时间旅行惊悚小说，你可以轻易想象它被直接改编成电影，既令人愉悦又聪明；简而言之，是一部快节奏的精彩之作。
FLORENT DRILLON/MILLENNIUM IMAGES, UK
在《升华》中，Isabel J. Kim 构思了一个尝试跨越国际边界的人可能会最终分裂成两个独立个体的世界。例如，如果你离开故土去往新天地，但心中犹豫是否做出了正确的决定，你可能会在机场发现自己分裂成了两个。你的一个“实例”会离开，而另一个则会留下。在分裂瞬间，这些实例是完全相同的，但此后，他们的记忆和生活将各不相同……除非他们恰好发生了肢体接触，在这种情况下，他们可能会重新整合，两个自我再次碰撞融合。
这无疑是一个复杂的设定，但请不要被它吓跑。作品的执行轻盈且优雅，设定的复杂之处被证明既动人又发人深省。Kim 让一个人被分裂成两个这件事显得非常自然——就像这个世界一直以来就是这样。她还使用了不寻常的第二人称视角。两个示例句子：“你摇了摇头。” 以及：“你抓了抓手腕上的黑色袖口。” 在不够成熟的笔触下，这可能会令人困惑。而在这里，它显得亲密且有趣。我们的女主角是首尔的一位年轻女性 Soyoung。我们第一次见到她时，她正在思考：违背对方意愿与其实例重新整合是否等同于谋杀——这无疑是一个极具张力的伏笔。
“《升华》的设定很复杂，但不要被它吓跑。其执行轻盈且优雅。”
Soyoung 在纽约有一个从未交流过的实例；那个版本的她现在自称为 Rose。与此同时，Soyoung 的好朋友是一个名叫 Yujin 的男人，而他恰好在纽约也有一个实例。Yujin 与他的实例 YJ 关系非常密切，两人正为了共同目标而合作。他们计划在达到 30 岁时重新整合。或者说，这至少是最初的计划，但它已经被……
如果两个版本的你相遇——并且接触了，会发生什么？
很久没有如此统一， 所以也许一切并非表象所见。 在与素英（Soyoung）共有的祖父去世后，罗斯（Rose）回到韩国，她与素英第一次见面。这次会面十分尴尬，因为这两个女人互不信任，而且理由充分。她们的重逢引发了一系列戏剧性事件，很快将裕真（Yujin）及其副本 YJ 卷入一场高风险的连锁反应中。 这是一部紧张的心理惊悚小说，充满了意想不到的转折。其文笔极佳，结构精巧。至于那些涉及大科技公司和反派被揭露的常规动作惊悚元素，我认为可以省略，因为在几组副本之间已经发生了这么多事情，这本书并不一定需要这些情节。但这只是一个小小的抱怨。这是一部顶尖的作品，是一个极佳的处女作。 本周的第二个推荐，献给那些喜欢非常“温馨”科幻作品的读者。《Moss’d in Space》，作者是丽贝卡·索恩（Rebecca Thorne），讲述了一艘覆盖着智能……苔藓的外星飞船。是的，《Moss’d in Space》讲的是关于苔藓的故事。更准确地说，是一个名为 Moss 的苔藓生物。在读进去之前，我觉得这个书名很糟糕，但读到一定程度后，我认定它是天才之作。 温馨小说绝对不是我的菜，而且这本书甜得像棉花糖一样，但我把它读完了，因为品质决定一切，而这本书品质极高。索恩拥有极其幽默的天赋，书中的笑点优雅地刻画在 Moss 对自身的认知（一个令人愉悦、容易相处的个体）与 Moss 实际狡猾、固执、容易生气性格之间的鸿沟之中。这是系列丛书的第一部，值得大获成功。 ❚
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复杂度塑造了我们对宇宙的看法
7月18日，第 40 页 来自 Carl Zetie，北卡罗来纳州，罗利 Stephen Wolfram 提出宇宙本质上是一台计算一系列状态的计算机，这提醒了我：就我们所知，人类一直以来都在通过将物理世界与当时他们所知的最复杂事物进行对比来描述它。 在史前时代，这个最复杂的事物就是我们自己，因此我们用心怀恶意的神灵和反复无常的幽灵来解释宇宙，而这些神灵和幽灵在很大程度上就像我们一样。 由艾萨克·牛顿、尼古劳斯·哥白尼和伽利略·伽利略发起的科学革命，催生了基于微分学的物理定律以及（理论上）具有精确解的方程，因此宇宙被描述为可以想象的最复杂的时钟机构。 在 19 世纪，随着统计理论的兴起和工业革命的到来，我们从热力学的角度去思考它——就像一台极其复杂的蒸汽机。到了 20 世纪，数字计算机出现了——那么，我们开始用信息论和可计算性来理解宇宙也就不足为奇了。我预测，只要时间足够，且人们更加熟悉，宇宙很快就会被比作一台量子计算机。 每当我们面对一个关于宇宙真实面貌的模型时，我们应该停下来问问自己，我们看到的是一个新想法，还是一个陈旧的错误。
关于世界上速度最快蜘蛛的思考
7月4日，第 16 页 来自 Talia Morris，澳大利亚，昆士兰州，凯普特里比尤莱申 你们报道称，在澳大利亚昆士兰州发现的一种蟹钳蛛被冠以“世界最快”的称号。作为昆士兰州凯普特里比尤莱申的居民以及当地蟹钳蛛的长久之友，我可以为它们的速度提供另一种解释：性格。 蟹钳蛛天性胆小且紧张。逃跑是它们的主要生存策略。一旦听到突然的噪音、被吹了一口气或光线发生变化，蟹钳蛛就会迅速逃离。你前一秒还能看到它们，后一秒就没了。
来自 John Newton，英国，伍斯特郡，罗斯伦奇 在英国我家的厨房木地板上，我观察到一些小蜘蛛移动速度确实非常快。它们的直径不到 2 毫米，小到我无法辨认。速度难道不应该相对于体型来衡量吗？
70多岁时的刺激性工作改善了我的记忆力
6月20日，第 38 页 来自 George Wallace，英国，汉普郡，法恩堡 我读了你们关于“超级养老者”（superagers）的文章，这些人直到 80 或 90 岁仍能保持异常敏锐的记忆力。我今年 71 岁。在我 70 岁从从事复杂系统的工作中退休之前，我的大脑似乎在变慢。我的工作虽然听起来很宏大，但其实要求并不高。我发现自己会忘记事情和人们的名字。 我的退休生活仅持续了 4 天。很快一家辅导公司联系我去教数学。我开始接学生，但发现我必须重新参加 GCSE 数学考试，因为考试内容变化太大了。完成之后，我开始学习 A level 数学。这让我和我的学生一样忙碌。大约一年后，我开始注意到一个深刻的变化：我的记忆力开始变得非常敏锐，我能记住以前模糊不清的事情。此外，我还通过每周竞走 40 英里来保持健康。
适应气候变化意味着接纳核能
想要联系我们？ 请将信件发送至 letters@newscientist.com； 条款详见 newscientist.com/letters 寄至 New Scientist, 9 Derry Street, London, W8 5HY 的信件将会延迟收到
社论，7月4日 来自 Mark Pickin， 英国北约克郡，伊辛沃尔德 在《Rising heat》（上升的热量）一文中，你们提到我们必须迅速采取行动以适应气候变化。对我而言，摆脱这一困境的唯一方法是投资于一种环保且合理的无碳能源，它能够按需生产我们所需能量，且其消费成本能使化石燃料在经济上变得不可行。 唯一真正合理的t技术是核聚变，但这仍然过于遥远。我们需要接受这样一个事实：在中短期内，小型模块化核裂变反应堆是唯一可以填补空白的现成解决方案，且化石燃料在接下来的 20 年里仍将是重要的能源。这使得我们别无选择，只能通过争取时间，并寻找某种方法至少能减缓气候变化的进程。 火山爆发能够显著冷却地球，这是无可争辩的，因此利用地球工程来模拟这种效果似乎合情合理。
低估 SpudCell 将面临风险
7月11日，第 8 页 来自 Peter Bickerton， 英国诺福克郡，南伍顿 Michael Le Page 向我们介绍了 SpudCell，这是一种部分能够自我复制的合成细胞原型。文章询问这是否可能具有危险性，并大胆地回答了“不”。
但我们难道如此傲慢，以至于认为自己能够阻止进化吗？微生物时刻在交换遗传信息片段，并且能够避开我们最努力的压制。合成生物学家过于自信地摆弄着一些我们甚至远未完全理解的东西，这已经远远跨越了傲慢的界限。
一位铁器时代部落首领的惨剧结局？
6月20日，第 13 页 来自 John Woodgate， 英国埃塞克斯郡，雷利 你们写道，考古学家发现证据表明，一名被埋葬在铁器时代英国的女性在死后可能被取出了大脑。 我可以想象这样一个场景：该女性是一位显赫的部落首领，而与她合葬的少年是她的继承人。也许他们在一场伏击中被敌对部落杀害，女性的骨骸遭到了亵渎。随后，她的遗骸与那个少年的遗骸被寻回，她被荣誉地重新安葬。 当然，这纯属推测；电影和电视改编权现已出售。
阅读 50 年后，仍有更多值得学习
6月20日，第 30 页和第 34 页 来自 Dave Holtum， 英国巴斯 我断断续续地阅读《新科学家 (杂志)》已经 50 多年了，一直很享受它带来的新视角。不过，在同一期杂志中出现两篇关于我从未听说过的事物的文章并不常见。我指的是凝聚体（coacervates）——发现于我们细胞中的神秘液滴，以及一种被称为多体定位（many-body localisation）的奇异物质状态。这提醒了我自己的浅薄，以及我个人和整个科学界仍有很长的一段路要走。 ❚
STEPHAN SCHMITZ
秩序与混沌。先天与后天。阴与阳。我们习惯于将世界一分为二。起初，物理学似乎也顺从了这一点。看看宇宙中那些杂乱无章的基本粒子，它们似乎可以分为两个阵营。将其简化到极致，你得到的是物质和力。两者共同构成了一个令人愉悦且简单的现实配方。
然而，物理学总有破坏简单配方的方法。在近期的数学研究中，研究人员发现了一种潜在的第三类粒子。这些所谓的“准粒子”（paraparticles）既不是物质，也不是力，而是一种处于两者之间更奇异的存在。而且，与玻色子（bosons）或费米子（fermions）不同，它们将遵循一套不同的量子规则——这套规则在几十年前被首次提出，随后在很大程度上被忽视了。
得益于新的数学洞察，准粒子可能比任何人想象的都更具可行性。虽然目前尚未在自然界中发现过此类粒子，但其影响深远。如果准粒子确实存在，它将撼动我们对现实的认知。
粒子物理学的标准模型是我们目前关于宇宙基本组成部分最好的理论，但它已经存在漏洞：它忽略了引力，且无法解释暗物质或暗能量。而准粒子可能为填补这些缺失部分提供一条新途径。牛津大学的 Vlatko Vedral 表示：“这将产生巨大的影响，它可能意味着标准模型存在严重的错误。”
为了理解为什么准粒子曾被认为是不可能的，回顾一下我们已知存在的两类粒子会有所帮助。一种是费米子，例如电子和夸克，它们构成了物质。另一种是玻色子，例如光子。
Miriam Frankel 发现，这让人们寄希望于它能解释最深层层面的现实
以及传递力的胶子。它们共同构成了标准模型中的所有基本粒子。物质与信使：这两者之间的划分并非仅仅是表面的；它似乎被写进了量子力学的数学结构之中。
量子力学以一种奇异但严格的方式处理粒子。两个电子不仅仅是非常相似。就理论而言，它们是可以互换的。在数学运算中交换它们的位置，任何实验都无法察觉到发生了什么。
这里涉及的数学工具是波函数：一个编码粒子处于特定状态（由位置、能量和自旋——一种内部角动量等属性定义）概率的数学对象。波函数包含一些看起来很奇怪的分量，包括负号和虚数。但实验产生的结果永远是普通的概率。为了获得这些概率，物理学家会对波函数进行平方，从而使某些数学上的奇异性在视觉上消失。
这意味着，当两个相同的粒子互换时，会出现两种可能的结果：波函数可以保持原样，或者改变符号。平方之后，两种选择都会给出相同的正概率。但在物理上，它们描述的是截然不同的粒子类型。
在一种情况下，相同的粒子可以聚集在一起。这就是玻色子，该家族包括传递电磁力的光子，以及携带强核力（将夸克结合成质子和中子）的胶子。因为玻色子可以同时具有相同的量子属性，所以它们往往相当“好交际”。例如，光子可以在激光束中堆积在一起。
在另一种情况下，相同的粒子被禁止共享一个量子状态。这就是费米子，包括电子、夸克和被称为中微子的幽灵粒子。在数学上，它们被禁止重叠，这使得电子变得“反社会”，并解释了为什么它们占据原子核周围不同的电子壳层。这也是普通物质具有顽固坚固性的原因：如果将原子挤压得太紧，它们的电子就无处可去，从而产生一种抵抗进一步压缩的量子压力。
神奇的数字
几十年来，这似乎已经穷尽了所有可能性。没有明显的第三种选择。但在 1953 年，物理学家赫伯特·格林 (Herbert Green) 发现了一个。他建议波函数内部可能比物理学家之前假设的具有更复杂的结构。当两个相同的粒子交换位置时，波函数并不一定只是保持不变或改变符号，它还可以重新排列那些在常规测量中不会直接显现的隐藏内部状态。
想象两个外观相同的盒子。从外部看，交换它们不会改变任何事情：同样的盒子依然在那里，任何常规检查都会得出相同的结果。但如果内部有看不见的隔间呢？如果是这样，即使内部隐藏的东西发生了变化，外部的相同性依然得以保持。这些通常被称为“隐藏状态”，而拥有这些状态的粒子被命名为“准粒子 (paraparticles)”。
这些隐藏状态成为了人们质疑准粒子的根源。没有人知道它们在物理上对应什么。它们可能仅仅是一个数学技巧，或者它们可能类似于自旋——一个没有直接经典对应物的量子力学属性——只不过它们被隐藏在常规测量之外。德克萨斯州莱斯大学的卡登·哈扎德 (Kaden Hazzard) 表示：“赋予它们的物理意义将取决于它们在真实物理系统中究竟是什么。”
正因如此，格林面临着艰苦的斗争。里约热内卢巴西物理研究中心的理论物理学家弗朗切斯科·托潘 (Francesco Toppan) 说：“早在开始时，人们就开始问：‘如果这些东西存在，为什么我们观察不到它们？’人们争论说，你之所以看不见它们，是因为它们实际上等同于玻色子和费米子。”
在 1971 年，这一观点似乎占据了上风。
新科学家 (杂志) 音频 您可以聆听许多文章——请在我们的应用程序中寻找耳机图标 newscientist.com/app
三位物理学家——塞尔吉奥·多普利切尔 (Sergio Doplicher)、鲁道夫·哈格 (Rudolf Haag) 和约翰·E·罗伯茨 (John E. Roberts)，统称为 DHR——证明了在三维世界中，任何关于准粒子 (paraparticles) 的理论都可以被重新阐述为伪装成普通标准模型物理学的理论。空间本身会迫使准粒子的行为表现为费米子或玻色子，而他们的结论很快就成了教科书式的定论：准粒子是一个有趣的想法，但并不真实。尽管如此，仍有人不气馁。在 20 世纪 80 年代，诺贝尔奖得主弗兰克·威尔切克 (Frank Wilczek) 证明，被限制在二维空间中的粒子（例如在薄层材料中）确实可以遵循不同的规则。他将它们称为“任意子 (anyons)”，这是对既有正统观念的一次重大挑战。“当我最初提出任意子时，我把它仅仅当作一种消遣和好奇心，”威尔切克说，“但很快它们就在实验中出现了。”不过，它们并非以自由漂浮的基本粒子形式出现。任意子
出现在某些材料中，被称为“准粒子 (quasiparticles)”——即表现得像粒子一样的集体扰动。声子 (phonon) 是一个更简单的例子。它本质上是一个声波包，由材料中振动的原子产生，类似于在挤满观众的体育场中传播的“人浪”。没有一个人本身就是波，但波的移动就像它本身是一个物体一样。即便如此，任意子现在被认真地视为容错量子计算机的潜在构建模块。2024 年的一项实验表明，通过交换它们的位置，可以将信息存储在一种对错误更具韧性的形式中。但任意子看起来像是 DHR 建立之规则的一个特殊漏洞：在实验室中奇特且有用，但远未达到反驳标准模型宏大二元论的程度。在三维空间中，让准粒子发挥作用要困难得多。2021, Toppan 尝试
在实验室中引入一种不同的代数来描述准粒子。利用这种数学方法，他发现普通空间不再强迫准粒子塌陷回费米子或玻色子。诀窍在于不再逐个观察粒子。在单独状态下，它们仍然可以被视为普通粒子，但在群体中，它们共有的量子态携带了一个额外的数学指纹，这是准粒子所特有的。但严重的问题依然存在。对于玻色子或费米子来说，在波函数中交换两个相同的粒子并不意味着这必须在现实世界中发生。没有人真的在把一个电子拖到另一个电子周围。相反，你只是在更改标签：被叫作 A 的粒子现在变成了 B，反之亦然。由于电子是全同的，任何可测量的量都不应该发生变化。
“当我最初
我认为它
一种好奇心。
但很快它们
出现了”
准粒子（Paraparticles）似乎有所不同。交换它们的标签还会改变其他东西：它们的隐藏状态。尽管目前尚不清楚这在物理上对应于什么，但重新标记似乎会产生实际的影响。现在，将一个准粒子放在地球上，另一个放在冥王星上，你会发现交换它们的标签违反了一个被称为“局部性”（locality）的原则，该原则认为遥远的物体不能瞬时地相互影响。
但一个针对这一曾经致命问题的解决方案最近出现了。王志远（Zhiyuan Wang）当时是莱斯大学（Rice University）的一名博士生，现就职于德国的马克斯·普朗克量子光学研究所（Max Planck Institute of Quantum Optics）。在 covid-19 封锁期间，他被困在室内，通过数学来消遣。“这挺有意思的，”他的同事兼前导师 Hazzard 说。王面对封锁带来的无聊所采取的应对方式是“摆弄代数表示”。但当王向他展示计算结果时，Hazzard 立即产生了浓厚的兴趣。
利用 Toppan 代数的一个类似但扩展后的版本，王和 Hazzard 将粒子重新标记的数学问题重新与物理运动联系起来。在 2025, 年发表的一篇论文中，他们展示了只有在粒子……
他们出于好奇而提出了这些方案，
STEPHAN SCHMITZ
实际上是通过一个粒子绕另一个粒子移动来交换的。这个过程需要时间，因此不会允许超光速信号的传递。“这是一篇绝对出色的论文，”Toppan 说道。Wilczek 将这一发现描述为“有趣”且“引人入胜”，但表示还需要更多的理论支持。Wang 和 Hazzard 展示了准粒子（paraparticles）在交换时的行为，但尚未揭示它们如何移动或相互作用的完整故事。“任意子（Anyons）的不同之处在于，我们可以追踪粒子的整个移动历史，”他说道。即便如此，Wang 和 Hazzard 的工作表明，准粒子可能以准粒子（quasiparticles）的形式存在，且能存在于比任意子更高的维度中。“新类型的准粒子可能会为我们提供一些我们此前未意识到可能实现的特性材料，”Hazzard 说道。例如，承载准粒子的材料可能会以全新的方式传导热量或电荷。Wang
还认为这在秘密通信中可能有有趣的应用。想象两方想要交换信息，但不想发送可能被拦截的常规信号。原则上，交换准粒子可能允许将信息编码在它们的交换过程中，而不会留下同样可测量的痕迹。虽然新准粒子的可能性可以开启新技术，但更大的奖项在别处：准粒子不仅存在于材料内部，而且作为一种新型的基本粒子存在。“认为这些可能是基本粒子的想法具有极强的推测性。这似乎有点像是一个绝望的念头，”Hazzard 说道。“但当你与那些致力于寻找新基本粒子群体的人交谈时，你会发现我们确实有点绝望。”目前还没有人确切知道此类粒子将扮演什么角色，或者它们将如何与我们已知的粒子相互作用。但它们几乎肯定会表现出与标准模型中任何粒子都不同的行为。玻色子乐于聚集在一起，而费米子则被禁止这样做。准粒子将遵循一种更奇怪的共存规则：既不是完全自由地堆积，也不是完全被禁止重叠。它们将为粒子共享宇宙的量子地产引入一种新方式。一个特别诱人的应用问题将是暗物质之谜。我们知道星系被包裹在巨大的不可见物质晕中，但我们仍不知道这是由什么组成的。Hazzard 已经开始与同样在莱斯大学的宇宙学家 Andrew Long 和 Mustafa Amin 共同探索准粒子是否符合这一条件。
ESA
他们表示，费米子无法共享同一量子状态的情况设定了一个限制。“如果暗物质粒子的质量低于电子质量的约 1/500,000，那么暗物质就不能由费米子组成，”Long 说道。出于这个原因，极轻的暗物质候选者——例如假设的轴子（axions），它们与普通物质和光的相互作用非常微弱——通常被视为玻色子。 但 Amin 意识到，准粒子的新“社交规则”可能使它们足够轻，从而能够形成暗物质晕。这个想法目前仍处于初步阶段，但这是一个引人入胜的提案。“我认为研究暗物质的人会对‘有一个全新的调节旋钮可以拨动’这个想法非常感兴趣，”Long 说道。
奇异行为
证明副粒子（paraparticles）的存在并非易事。它们的定义性隐藏状态无法被直接测量。相反，物理学家必须通过间接方式来寻找它们。
Toppan 最近提出了一种这样的测试。想象两名科学家在一对粒子交换前后对其进行监测。对于普通的玻色子或费米子，测量结果应该是完全一致的。而对于副粒子，隐藏状态会微妙地改变底层的波函数，从而在数据中产生一个显著的不对称性，即便这些粒子本身看起来仍然相同。
宾夕法尼亚州立大学的 Hazzard 和 Bryce Gadway 希望在超冷原子链的类副粒子状态中寻找这种效应。这并不等同于发现了某种基础副粒子，但
[[IMG_XXXX]] 填充中子星的中子是费米子， 这是两种传统粒子类型之一
它将证明这些奇异的行为可以在真实的物理系统中出现。另一方面，寻找一个基础副粒子则是一项更艰巨的任务。实现这一目标的一条可能路径是通过粒子加速器。“你需要做的是加速某些粒子，引发级联反应，然后观察结果，”Vedral 说道。这意味着将粒子碰撞在一起，让碰撞产生新粒子，然后在碎片中寻找模式。原则上，副粒子可能会携带粒子交换位置时隐藏状态变化的印记。
但也许在现有的数据中就能看到证据。如果副粒子对暗物质、暗能量或其他宇宙现象有贡献，它们的指纹可能已经隐藏在对宇宙的观测之中。Vedral 等人建议在宇宙微波背景（即大爆炸留下的残余辐射）中寻找它们的影响。“其中一种可能性是，某种副粒子相互作用产生了一定的贡献，”他说。英国约克大学的 Kasia Rejzner 表示，这是“寻找它们最简单、最廉价的方式”。
目前，副粒子仍然是一个数学上的可能性，而非物理现实。很多事情仍然未知，包括它们的质量、自旋和完整的动力学特性。Wang 和 Hazzard 目前正致力于将它们纳入一个完全相对论性的量子场论（现代粒子物理学的语言）之中。这种努力是会揭示一种新型粒子，还是会再次关闭这扇门，目前仍未可知。但如果副粒子能经受住这种检验，它们可能会以我们难以想象的方式改变标准模型。
Hazzard 表示，甚至有可能某些我们已经熟知的费米子或玻色子，如果在测量精度足够高的情况下，可能会揭示出类副粒子的行为。“有些人联系我们说：‘我们究竟在多大程度上确定电子实际上是一个费米子？’”他说。这是一个发人深省的问题。物理学有时能将现实看作黑白分明。但副粒子是一个至关重要的提醒：自然界最清晰的界限，往往正是需要重新审视的地方。 ❚
Miriam Frankel 是一位常驻伦敦的科学记者
ASHLEY COOPER/SCIENCE PHOTO LIBRARY
在你脚下的深处，地球是炎热的。 非常炎热。其中的一部分热量是行星剧烈形成时期残留的。 更多热量则是由下方岩石中放射性原子的分裂不断产生。在少数地方，地球隐藏的熔炉会剧烈地显现出来，以火山、间歇泉和岩浆河的形式冲破地壳。 这些景象令人惊叹，但如果能加以利用，它们也非常有用。传统的地热能 (Geothermal power) 在地质条件已经为我们铺好路的地方效果最好：即在断层线劈开地壳，热水或蒸汽上升到接近地表的地方。这就是为什么冰岛、新西兰、肯尼亚和印度尼西亚等国家能将地球的热量转化为家庭暖气和电网电力，而世界上大部分其他地区则几乎未触及这一资源。 它的吸引力显而易见。与太阳能不同，地热能不会在日落时消逝；与风能不同，它不会在无风时停滞。 在过去十年中，钻探技术的进步已开始将地热能从地质枷锁中解放出来。一些项目旨在改进自然条件，在原本没有裂缝的地方创建裂缝和通道。另一些项目则更为雄心勃勃：他们希望钻得足够深，以便地热能在几乎任何地方运行。“最终，全世界都是目标，”地热能公司 Quaise Energy 的联合创始人马特·侯德 (Matt Houde) 说道。 这将使它从一种小众资源转变为规模大得多的东西——一种在任何我们需要的地方都能挖掘行星隐藏热量的方法。 为了将地球内部的热量转化为可用能源，工程师们将冷水泵入热岩中自然形成的储层。在那里，水被加热并以热水或蒸汽的形式返回地表，
冰岛 将其大量能源 源自地热
用于驱动涡轮机并发电。然后，水被送回地下，开始新一轮的循环。 这是一个简单的概念，而且与化石燃料不同，地热热源在人类的时间尺度上几乎是无穷尽的。“如果你以地壳中储存的能量来衡量，地热能比所有碳氢化合物高出几个数量级，”侯德说。问题在于，传统地热能的运作需要三个要素：热量、水，以及具有足够渗透性或裂缝以便水通过的岩石。“传统的地热系统非常局限于那些拥有这种独特条件组合的国家和地区，”他表示。 这就是为什么地热能在冰岛等地蓬勃发展。该国跨越中大西洋海岭，拥有异常丰富的这些核心要素。20 世纪 70 年代的全球石油危机促使冰岛利用这一优势，如今地热能占该国电力供应的四分之一以上。这听起来可能不多，但冰岛的地热电站无论天气如何都能持续发电，使其成为电网的稳定支柱。 “地热能非常适合成为让低碳电力系统运转起来的‘粘合剂’，”伦敦帝国学院的可持续能源专家伊恩·斯塔费尔 (Iain Staffell) 说道。 然而，大多数国家并没有冰岛那样幸运。它们可能拥有热量、水或裂缝岩石，但并非三者同时处于易于触及的深度。传统的地热电站仅限于开采地下 2 公里以下的深处热量。
储存的能量来看， 地热能比所有 碳氢化合物 高出几个数量级”
DIETER TELEMANS/PANOS PICTURES
如果钻得更深，工程难度将变得极其巨大。钻头必须凿穿坚硬且高温的岩石。连接地表与热储层的垂直井道（即井）必须在极高温度和压力的严酷环境下生存。即便如此，岩石可能仍然过于致密且未破碎，导致水无法在其中流动。
尽管如此，潜在回报依然惊人。国际能源署估计，假设我们能够开发深度约为 8 km 的热量，地热能的技术潜力约为目前全球电力需求的 150 倍。传统的地热能通常开采地下 2 km 以下、具有渗透性且破碎岩石中预先存在的热水或蒸汽储层，这使得大部分潜力无法触及。这意味着：为了扩大资源利用，工程师必须钻得更深——并创造出自然界尚未提供的地下管道系统。
第一种新型地热技术正是如此。增强型地热系统 (EGS) 针对的是高温但不可渗透的岩石，通常位于地下 2 到 10 km。工程师以高压注入热水，以打开或拓宽裂缝，从而为流体循环创造路径（见右侧“地热能如何开辟新领域”）。这是地热能新 era. 中最成熟的技术。
但这种方法也有缺点。将水强行注入深层岩石不仅会产生有用的裂缝。根据 2023 年的一项研究综述，它还可能扰动那些早已存在的古老断层。
在冰岛的蓝色湖（Blue Lagoon），地球的热量温暖了天然潟湖，并被提取用于房屋供暖。
非常适合 作为一种纽带， 使低碳电力 系统得以运作”
处于压力之下。许多断层由于摩擦力而保持静止，就像一本沉重的书放在倾斜的桌子上一样。向其中注入水，其孔隙和裂缝中的压力就会上升。这有助于将断层的两边撑开，从而减少将它们夹在一起的压力。如果断层已经接近滑动状态，这可能足以诱发地震。
循序渐进
一项由韩国政府委托的调查得出结论，一个附近的增强型地热系统（EGS）项目在 2017. 年在浦项市引发了一次 5.5 级地震。超过 80 人受伤，地震造成的损失估计达 300 billion 韩元（£148 百万英镑），使其成为该国历史上破坏性最大的地震。加利福尼亚州斯坦福大学的 Bill Ellsworth 是协助确定地热电站在此次灾难中扮演何种角色的小组员之一。“在浦项，他们钻了几个距离较远的井，”他说。当时的希望是通过向其中一口井注入水，使岩石产生足够的裂缝以与另一口井相连，从而为水在两者之间流动并聚集热量创造路径。但试图在地下强制建立这种连接是具有风险的，特别是如果钻孔穿过了已经准备好滑动的断层。
Ellsworth 表示，这就是为什么较新的项目试图更加谨慎的原因。例如在冰岛，工程师们尝试通过缓慢且在相对较低的压力下注入冷水，更温和地创建 EGS 储层。冰岛能源公司 HS Orka 的资源执行副总裁 Lilja Magnúsdóttir 表示，在数月的时间里，冷却的岩石会收缩并产生裂缝。冰岛还拥有一个由必要性带来的优势：那里是一个地震活动频繁的地方，因此该国已经在监测方面投入了大量资金。在 HS Orka，这现在包括将地热井本身用作预警传感器。当岩浆开始移动时，它会压缩周围的岩石，在井中产生一个标志性信号。“这是一个非常酷的设计，”Magnúsdóttir 说道。但即使在 EGS 项目已经学会管理地震风险的地方，硬岩仍然不能作为管道系统的可靠基础。例如，流体可能会泄漏并污染地下水。而且，使系统发挥作用的那些裂缝也可能使其变得危险。一种解决方法是完全不再要求岩石承载水。在不存在天然裂缝和储层的地方，EGS 的替代方案是在热岩中钻一个密封回路。工程师向下钻孔，
然后向侧向钻进，直到钻孔在地下连接，之后用钢材和水泥对其进行衬砌和密封。这创造了一个类似于埋地散热器的结构，流体在其中循环，但永远不会与岩石本身接触。这种闭环系统被称为先进地热系统 (AGS)，它已经在德国得到了成功测试。加拿大的能源公司 Eavor 在 Geretsried 开发了一座地热能电站，该电站于 2022 年开始建设，并于去年开始发电。由于闭环系统不会强行撑开岩石中的裂缝，因此它们应该能降低诱发地震的风险。而且，由于它们不依赖于不断地将水泵入和泵出这些裂缝，风险应该会进一步降低。
此外还有一个潜在的优势。如果工作流体保持在密封管内，它就不一定必须是水。原则上，公司可以使用吸收和释放热量效率更高的流体。Eavor 的工作流体是公司秘密。与此同时，中国华能集团建设了首个使用超临界二氧化碳的地热示范电站——这种 CO2 被压缩并加热，直到它处于既非完全气体也非完全液体的状态。在这种状态下，它密度大且流动容易，非常擅长传递热量。该公司的测试设施于今年 5 月在中国郑州开始运行。
但这些系统也有其自身的困难。在岩屑堵塞部分管道网络后，Eavor不得不削减计划钻井的数量。其电站虽然在运行，但效率尚未达到预期。这指向了一个更广泛的问题：闭环系统能否循环足够的流体，并足够快速地从岩石中提取热量，从而具有商业实用价值？“目前尚无定论，”Ellsworth 说道，“时间会告诉我们，这种仅采用单一闭环的想法是否真的能成功。”
尽管 AGS 可能比在地下深处诱发裂缝更安全、更清洁，但它仍然被限制在热岩处于可触及范围（通常是地下几公里深）的地方。要让地热能真正全球化，公司必须钻得深得多，而且深得多。
钻得越深，地球的温度就越高。如果钻得足够深，水会跨过一个奇特的阈值。在约 374°C (705°F) 且压力足够的情况下，它会转化为超临界流体——类似于中国华能示范电站中的 CO2——且能携带比普通热水或蒸汽多得多的热量。“在少数几个国家，地热能确实提供了能源供应中相当大的一部分。但严格来说，热量本身——这才是地热能的本质——只要你钻得足够深，实际上在任何地方都可用，”Houde 说道。
超临界温度通常出现在至少 5 到 20 km 的深度，且往往更深。钻得越深，岩石就越坚硬：是玄武岩或花岗岩，而非通常在靠近地表处发现的较软的沉积层。这种岩石会磨损掉即便最坚硬的碳化钨或金刚石钻头。此外，还有大量时间并非用于钻进，而是用于更换磨损的钻头，或更换在高温和深层环境下开始失效的设备。Houde 表示，这些延迟迅速推高了成本。
[[IMG_XXXX]] 先进 地热能
地热能如何开辟新领域
增强型地热能通过制造地下裂缝，闭环系统像埋地散热器，而超热岩项目则钻至极深之处。这些共同展示了工程师们希望如何将地热能扩展到那些自然界尚未完成“管路铺设”的稀有地带之外。
增强型 地热能
冷流体进入
闭环 管道网络 管道网络
热流体流出
诱发裂缝 诱发裂缝
[[IMG_XXXX]] 增强型和 先进 先进地热 系统深度为 2–7 km
超热岩 地热系统 深度约为 ~10 km 或更多
超深 地热能
总部位于德克萨斯州休斯顿的 Quaise 公司希望通过一种不同的钻探方式来解决这个问题——完全不使用钻头。其计划是在井口上部使用常规钻探，一旦岩石变得过于坚硬，就切换到高功率微波能量。孔洞将由波纹钢衬砌，帮助微波向下传播。当能量击中岩石时，会将其加热直到岩石开裂、破碎甚至气化。“这里没有钻头在机械地破坏岩石，仅仅是能量与岩石之间的相互作用，”Houde 说道。
岩石将被还原成细小的灰烬，通过富氮气体从井中清除并在地面收集。Quaise 并非唯一追求非接触式钻探的公司：总部位于斯洛伐克的 GA Drilling 也在试用基于激光和等离子体的系统，并于 2023 年进行了首次现场测试。
ALESSIA PIERDOMENICO/BLOOMBERG VIA GETTY IMAGES
一旦孔洞开通，Quaise 希望创建一个深层的 EGS（增强型地热系统）风格的储层。水将被送入超热岩石的裂缝中，吸收热量后返回地面以发电。原则上，这就是摆脱了地理限制的地热能。
Quaise 的测试孔目前深度仅有几公里，但该公司将其视为更大规模项目的概念验证。其计划在俄勒冈州建立的首座超热地热电厂预计将在 2030, 年前投入运行，在 3 至 5 km 的深度获取高达 400°C (752°F) 的温度。未来的潜在选址将向更深处推进，可能达到 10 km。Houde 表示：“到 2035, 年，我们希望第一口超热井能在深度超过 10 公里的地方生产能源。”他认为，其公司的技术可以将任何地区都转变为地热资源区。
但仍然存在严重的不确定性。其中之一是如此深的井在地下数公里处的巨大压力下能否保持开放状态。“目前尚不清楚这是否可行，”Ellsworth 警告道。Houde 承认最艰巨的工程挑战在前方。“我认为，为了证明超热地热的可行性而达到这些初始深度是非常可行的，”他说，“我认为，在挑战我们可以深入的极限方面，难度将日益增加。”
冰岛让我们得以一窥这些不同的地热技术路径将如何融合。Magnúsdóttir 表示，冰岛并没有仅仅满足于作为全球地热成功案例之一，而是正迅速成为下一阶段技术的试验场。
该国最深的地热井——由冰岛深钻计划（Iceland Deep Drilling Project，一个由该国领先能源公司及其能源当局组成的财团）钻凿的第二口井——已经触及了超热地热的潜能。该井于 2017 年完工，深度达 4.7 km。Magnúsdóttir 说道：“这是世界上第一口在地下地热井中确认处于超临界状态的井。”冰岛的运营商还在利用 EGS 技术从现有区块中获取更多资源，通过刺激更深层的断层以获取额外一公里左右的热量。
QUAISE ENERGY
Quaise Energy 使用微波能量切开地球深处的坚硬岩石
一名工人正在检查意大利一座地热冷却塔的内部
地下钻了那个孔， 它就能维持 100 年以上”
明年，冰岛深钻项目（Iceland Deep Drilling Project）计划钻探其第三口井。“在那里，他们只需要深入 2 公里多一点就能达到超临界状态，”Magnúsdóttir 说道。但即便在如此相对较浅的深度，工程挑战依然十分严峻。主要问题是井筒的完整性。在如此高温下，衬砌井壁的钢套管可能会膨胀、变形并失效。在冰岛，工程师们一直在测试解决方案，包括在套管各段之间使用柔性连接件。如果地热能要赢得投资者的青睐，这类工程技术将至关重要。项目的前期投入高且验证周期长，而且开发商在确定某个地点是否具有商业可行性之前，通常需要获得许可。但耐心等待的回报可能是异常持久的。“它的成本非常、非常高，”欧洲地热能委员会（European Geothermal Energy Council）的 Sanjeev Kumar 说道，“但一旦你在地下钻了那个孔，它就能维持 100 年以上。”
这就是这个问题的缩影：既是承诺，也是难题。“我们知道，如果我们能触及极深层的地热能，那将是非常极好的，”Ellsworth 说，“我们只是还不确定这是否可行。” ❚
Katharine Sanderson 是一位 专注于物理科学的 科学记者
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是什么让一个国家感到幸福？作为最新一期《世界幸福报告》的编辑，
Jan-Emmanuel De Neve 告诉 Alexandra Thompson，我们可以从那些人们感到最满足的国家中学到什么
芬兰（FINLAND）听起来就像是一个极乐世界。几个月前，它在《世界幸福报告》中被评为最幸福的国家，与它的北欧邻国并列榜首，北欧国家占据了前六名中的五个席位。这并非偶然——芬兰已经连续九年排名第一。显然，有很多因素理应让北欧国家的人们感到不够满足，尤其是阴沉的天气和高额的税收。但另一方面，人们感觉到这些税款确实花在了实处，居民们享受着医疗、教育和交通投资带来的回报。此外，低人口密度、大规模的森林覆盖以及便捷的湖泊和海岸线，意味着即使是城市居民也永远不会远离自然。
但我们应该在多大程度上信任这些全球排名？毕竟，幸福是一个难以捉摸的概念，各种因素——尤其是不同文化对“幸福”含义的理解——都可能导致结果出现偏差。
为了探讨这些问题，《新科学家 (杂志)》采访了牛津大学的经济学家兼行为科学家、以及《世界幸福报告》的编辑 Jan-Emmanuel De Neve。他解释了他的研究如何尝试衡量真正的幸福，以及为什么他认为
芬兰理应占据榜首，而我们其他人可以做些什么，来为我们的日常生活带来更多快乐。
亚历山德拉·汤普森：您如何定义幸福——我相信这是一个极其简单且直接的问题。 扬-埃马纽埃尔·德·内夫：这个问题在 2500 年来一直被哲学家们关注，从亚里士多德开始就不止于此。我认为在 20 世纪 80 年代发生了一次阶段性的转变，当时心理学家开始将福祉定义为“主观福祉”，归根结底，就是人们对自身生活的感受。 长话短说，我们现在绕过了哲学争论，而是直接询问人们：“你对你的生活感到幸福吗？”这意味着我并没有强加一个关于福祉定义的标准。相反，我直接询问你：“在你的心中，你是否过着幸福的生活？”
2026 年的世界幸福报告最近发布了。你们是如何决定不同国家的排名的？ 我们使用的是盖洛普世界民意调查（Gallup World Poll）的一部分调查，该调查每年进行一次，涵盖近 150 个国家。在每个国家，他们至少有 1000 人的样本量，在性别、社会经济地位、城镇与乡村居住地等方面具有很好的代表性。 我们从主观福祉开始，要求人们想象一个有 10 级横杠的梯子，最高级是你能想象到的最好生活，最低级是你能想象到的最糟生活。然后我们询问：“你认为你现在处于哪个位置？”这给了我们一个 0 到 10 的分值。这并不是在衡量人们是否在街上跳舞或在屋顶上歌唱，而是一种满足感。年度排名随后基于过去三年的移动平均值。 接着，科学研究就介入了。我们对结果进行逆向工程，利用客观衡量指标（如人均 GDP、健康预期寿命、人们是否有可以依赖的朋友等）来分析哪些因素可能解释了国家之间的差异。我们还使用调查来衡量慷慨程度，以及这些国家的人们通常感受到的是积极还是消极的情绪。
芬兰，工作与生活的 平衡被视为 更为重要，因此 人们实际上 有时间过上 丰富的社交生活”
在这份报告中，北欧国家占据了前六名中的五个席位，而美国排名第 23 位，英国排名第 29 位。北欧国家究竟做对了什么？ 首先，它们拥有高水平的经济生产力。但与许多其他高收入国家不同，其财富分配更为均匀，因此收入不平等程度远低于美国等地区。而且我们根据之前的研究知道，在其他因素相同的情况下，更大的收入不平等与较低的幸福感相关联。 第二点是，资金通过福利国家进行分配，这最大限度地减少了经济焦虑并建立了社会安全网。在美国与在芬兰，被裁员或失业的感受将截然不同。 此外，这些国家还有一个“健康预期寿命”的概念，它衡量的是人们预期能以良好健康状态生活的时间，而不仅仅是寿命。
RAGNAR TH SIGURDSSON/ARCTIC IMAGES/ALAMY
最被低估的是社交纽带的重要性。我们的研究将幸福感与一些替代指标联系起来，例如你一周共享用餐的次数，以及在紧急情况下是否有可以依赖的朋友。这些国家的人们比在英国或美国拥有更多陪伴家人和朋友的时间，而在后者，工作吞噬了我们大部分的清醒时间。在丹麦或芬兰，工作与生活的平衡被视为更为重要，因此人们实际上有时间过上丰富的社交生活。 他们还拥有高水平的社会信任。我们可以通过“丢失钱包”的问题来看出这一点，该问题是：“如果你丢了钱包，你认为找回它的可能性有多大？”我们发现，在北欧国家，人们认为钱包被归还的预期频率远高于其他地方。这对他们的幸福感产生了积极影响。
我们如何知道高水平的社会信任是导致更高幸福感的原因，还是其结果？ 这是一个“鸡生蛋还是蛋生鸡”的问题，但实际上两者兼而有之。如果你处于一个充满信任的环境中，这将提升你的幸福感。而当人们感到幸福时，他们会更具亲社会性。看看志愿者活动：参与志愿服务的人更幸福，而如果你更幸福，就更有可能去做志愿者。这是一种协同的动态关系，箭头指向两个方向。
投资于面对面 的人际关系 对幸福至关重要
IGOR SOKOLOV/ALAMY
芬兰与其他北欧国家有何不同？在过去九年的报告中，芬兰一直占据第一名的位置。 我认为有两个要素使其脱颖而出。芬兰在广袤的国土上人口稀少，而且似乎每个人在森林里的某个湖边都有一栋小屋。因此，这种与自然的联系非常深厚，而且已有大量记录证明，在户外活动能增强福祉。它能改善情绪，减轻压力，降低血压——如此之类。 大多数芬兰人对生活感到满足，这一事实表明他们可能比其他北欧国家的人更务实。他们并不奢求遥不可及的目标；他们对自己拥有的一切感到满意，而这正向地影响了他们的主观幸福感。
考虑到芬兰的冬季白昼是欧洲最短的地区之一，其排名如此之高令人惊讶。您是否研究过这一现象的影响？ 虽然芬兰的冬季白昼可能最短，但相应地，其春季和夏季的白昼则是最长的。他们还将季节变成了某种特别的体验。因此，在冬天，他们把家里布置得温馨舒适；而在夏天，芬兰则充满了生命力，人们充分利用湖泊和森林。
在解释这些调查结果时，您如何考虑文化差异？例如，在丹麦，满足感是国家认同的一部分，而英国则有著名的格言“保持冷静，继续前行”。 在每种文化中，关于预期与非预期之间都存在着独特的习惯和社交心理。我们尝试通过退后一步，让人们在一个阶梯上评估其生活质量来解决这些问题。因此，这比单纯询问他们是否快乐地更加全面。 此外，在不同文化之间，福祉一词的翻译和解读也存在细微的语言差异。但这些语言差异并不剧烈到足以掩盖各国在“什么是美好生活”这一定义上的差异。 我们在之前的报告中还评估了移民的影响，并发现如果有人移居到另一个国家，他们适应该国平均幸福感的速度之快令人惊讶。因此，如果一个英国人搬到加拿大，他们的起步分会稍低，然后你会看到他们迅速攀升至加拿大的平均水平；反之亦然。 所以，这不仅仅是文化预期的问题。这表明人们生活的环境至关重要。
哥斯达黎加在报告中排名第四，这是拉丁美洲国家迄今为止的最高排名。相比前一年的第 23 位，这是一个巨大的进步。是什么解释了这次跃升？ 如果你观察关于健康、预期寿命或 GDP 的人口指标，哥斯达黎加在福祉方面的表现远超其规模。我怀疑这部分是因为当地人们拥有强大的社会关系。这表明生活不仅仅在于财富或人均 GDP。 实际上，哥斯达黎加在 2012 和 2015 年之间排名相对较高，随后因未知原因下降，现在正重新回升。这可能是因为其他国家的排名下降了，但它也拥有政治稳定和繁荣的生态旅游业。这确实令人印象深刻。
基于您对幸福感的研究，您认为最大的变化会是
北欧国家 倾向于在全球 幸福感名单中 名列前茅
OLIVIER BOURGUET/ALAMY
想要看到什么样的举措能帮助人们感到更满足？ 这在不同国家之间差异巨大。通过政策手段能获得最大的幸福感回报。在英国，我们非常关注物理基础设施，这很重要，但社会基础设施呢？我们能否在社区方面投入更多，让他们凝聚在一起，无论是通过老年人的桥牌俱乐部，还是乡村地区的当地足球场？ 我还认为，我们可以开始重新分配由人工智能等新技术带来的生产力经济收益，例如实行每周工作四天但领取五天薪水的制度。《世界幸福报告》将在 2027 年更详细地研究这一举措的成效。在一个工作日中，我们被要求完成如此之多的工作，但我们的大脑与 1000 年前的大脑是一样的，因此人们感到压力巨大且焦虑。有几项政策可以在不耗费巨资的情况下切实提高幸福感。
在这些政策实施之前，作为个人，我们可以做些什么来让自己感到更满足，也许可以借鉴一些来自芬兰的建议？ 投资于面对面的关系；约人们一起吃午餐。我们需要在社交生活上投入更多。对于全职居家办公的人来说，这是一个特别需要关注的问题。如果你是混合办公人员，请尝试协调你的到岗时间，以便与同事共度高质量的时光。像视频通话软件这样的基础设施非常有帮助，但它似乎削弱了面对面的关系。这是一把双刃剑，我们需要意识到这一点。 ❚
Alexandra Thompson 是 新科学家 (杂志) 的助理新闻编辑， 专注于健康领域
A
生长爆发期
作为一个经常撰写人类进化与考古学文章的人，我见过大量关于史前人类的艺术想象图。有些图极其可信，尽可能地紧贴科学发现；而有些则不然。每当我看到非洲或热带古人类被描绘成北欧风格的苍白皮肤时，我都会感到不适；而当我看到无毛的古人类在英国等温带地区赤身裸体地游荡时，这种不适感会进一步升级。穿点衣服吧，否则你会冻死的。
然而，最让我困扰的是，许多关于史前人类的图像尺寸太大了。有时，这涉及到肌肉组织。你可以看到一些图片，其中的史前人类（通常是男性）拥有极其强健的体魄，肌肉隆起，仿佛他们一直在健身房做重复训练并饮用蛋白质奶昔。但实际的日常体能训练并非如此。如果你的身体看起来像电影里的超级英雄，那是一种美学选择——是通过生理技巧实现的，比如通过人工脱水使肌肉线条更加明显。真正的速度、力量和耐力并不是那样的外观。
除了这些表面美学之外，还有一个更深层的问题。史前人类无论是在体重还是身高上，都比我们要小。在极端的例子中，有像花 Flores 人（Homo floresiensis，被称为“霍比特人”）这样真正矮小的群体，但即便我们的直接祖先，整体上与现代人相比可能也偏小。
随着化石收藏的增加，人类如何变得更重、更高这个故事正慢慢清晰起来。而且，这似乎是我们起源过程中的一个重要部分。
为了了解古人类体型随时间变化的规律，我采访了英国雷丁大学的进化生物学家雅各布·加德纳（Jacob Gardner）。他是上个月在《美国国家科学院 PNAS》上发表的一项研究的首席作者，该研究探讨了过去 4 million 年间的体型趋势。
让我们先来看一些具体数字。在 2 million 年之前生活的早期古人类，如阿迪比斯猿（Ardipithecus）和南方古猿（Australopithecus），平均体重为 40 公斤，范围在 30 到 50 公斤之间。能人（Homo habilis）是我们属的早期成员，体型稍大一些：平均 45 公斤，范围在 35 到 55 公斤之间。直立人（Homo erectus）是已知首个从非洲迁徙到欧亚大陆的古人类，体型更大，平均 60 公斤，范围在 50 到 75 公斤之间。最后，史前智人（Homo sapiens）的平均体重达到了 75 公斤，范围在 55 到 80 公斤之间。
加德纳及其同事汇总了 386 份样本的体重估计值，这些样本属于 21 个古人类群体，时间跨度从 4.5 million 年前到 30,000 年前。如果这个时间范围看起来有些随意，那是由于特定原因。他们排除了更近期的样本，因为有证据表明我们的物种在过去 30,000 年中有所缩水，这会干扰分析。他们还剔除了
剔除了最早的人类祖先——萨赫勒原人（Sahelanthropus）和奥罗林原人（Orrorin），因为关于它们与后期群体之间关系的确定性仍然不足。随后，团队运行了 1000 个模型，以观察什么样的解释最符合数据。是每个群体内部的体型都在增加，意味着早期的直立人（H. erectus）比后期的更小？还是每个群体的大小基本保持不变，而变化发生在新群体演化之时？体型是在整个 4.5 million 年的时间跨度内逐渐增加的，还是经历了长期的停滞和偶尔的爆发式增长？
研究人员最终确定了两种趋势，这两种趋势共同解释了大部分的变化。
Gardner 表示，第一种是“从阿尔底原人（Ardipithecus）到后期人类物种的逐渐演进”。这是一种“温和”的体重增加，每百万年增加约 1 到 3 kg。请记住，平均体重在 4.5 million 年内从 40 kg 增加到了 75 kg：这种逐渐的增长只能解释其中的约三分之一。
因此出现了第二种趋势，Gardner 说，这是一个“在直立人（Homo erectus）以及我们人属（Homo）中其他后期物种出现前后的巨大飞跃”。第一批直立人大约在 2 million 年前出现在非洲。
关于这为什么会发生，我们稍后会讨论，但首先让我们看看人们的身高发生了什么变化。
[[IMG_XXXX]] 肌肉发达的体格更多是一种现代现象
CHUANG ZHAO
SHUTTERSTOCK
Gardner 和他的同事们没有分析身高，但由德国图宾根大学 (University of Tübingen) 的 Manuel Will 领导的一个团队在 2017. 发表在《皇家学会开放科学》(Royal Society Open Science) 上的一项研究中进行了分析。这项研究汇总了从 4.4 百万年前到直到近现代的 204 个身高估值。其变化非常剧烈。一个特别娇小的南方古猿 (Australopithecus) 标本的身高仅为 105 厘米，而一个来自意大利 Barma Grande 洞穴的 24,500 年前的智人 (H. sapiens) 身高则接近 189 厘米。
Will 的团队发现，存在“相对停滞的阶段，其间穿插着快速增长的时期”。在 2.2 million 年前之前，大多数古人类的身高不足 140 厘米。随后在 2 million 和 1.6 million 年前之间出现了明显的增长。到 1.6 million 年前，一些个体的身高首次超过了 170 厘米。然而，这种身高直到更近的时期，大约 500,000 年前才变得普遍。
这与 Gardner 团队的发现大致相吻合。从大约 2 million 年前直立人 (H. erectus) 出现起，古人类在质量和身高上都显著增加了。
发生了什么？答案，一如既往，是“很多因素共同作用”。
其中一个因素可能是性二形性 (sexual dimorphism)。在像南方古猿这样的早期古人类中，雄性明显比雌性大——170 厘米对比仅 105 厘米——并且拥有更大的犬齿。我们在黑猩猩和其他雄性[此处文本中断]的动物中也看到了相同的模式。
激烈地竞争雌性，成功的雄性会与多只雌性交配，而失败的雄性则完全无法交配。但在早期的原人（Homo）物种中，雄性和雌性的体貌要相似得多（而如今的人类 H. sapiens，其身高和体重的差异则更小）。
离奇的故事
这一切具体是如何演变的尚不清楚。“有一些假设认为，也许是雄性随着时间推移而变小了；而另一些假设则认为，是雌性随着时间推移而变大，而雄性则保持不变，”Gardner 说道。如果后者成立，这可以解释部分平均体型的增长。饮食可能也起到了重要作用。早期原人比南方古猿（Australopithecus）食用更多的肉类，而肉类具有高热量。此外，Gardner 表示，“我们正在直立人（Homo erectus）身上发现一些最早的烹饪肉类的证据”。熟食比生食包含更多热量，因此这是从给定食物源中获取更多营养的另一种方式。
花来原人（Homo floresiensis） 的身高勉强超过 100 厘米
熟食也可能是我们身体另一项重要变化——大脑生长——的一个因素。熟食提供的额外热量可能使我们的大脑能够进化得更大。同样至关重要的一点是，要记住不同的古人类群体根据其环境而以不同方式进化。因此，虽然整体趋势是体型变大，但并非所有人如此。生活在印度尼西亚弗洛雷斯岛直到 50,000 年前的花来原人（H. floresiensis），身高勉强超过 100 cm。生活在 335,000 到 236,000 年前的南非纳莱迪原人（Homo naledi）较高，但依然没有超过 140 cm 多少。已知最矮的成年古人类之一是一位强原人（Paranthropus robustus）女性，她的身高可能仅为 103 cm。我们不知道为什么这些古人类变得如此之小，可能每个人是因为不同的原因。Gardner 认为：“所有这些不同的物种都在寻找自己的进化路径。”他说，每个古人类群体都有其独特的一套环境背景，这反映在他们各异的体型上。最后，让我们反转这个问题。一旦像直立人（H. erectus）这样的早期原人群体进化出更大的体型，这如何改变了他们的生活？Gardner 说：“你的体型越大，你在地表行走时的步幅就越长。”这对直立人而言尤为正确，因为他们的腿相对于早期古人类来说比例更长。Gardner 认为，他们比之前的群体拥有更大的家域。这甚至有助于解释为什么直立人是（我们所知的）首批漫游到非洲以外的古人类。这是一个长期存在的谜题：为什么他们能一路走到爪哇，而之前的古人类似乎从未离开过非洲？如果 Gardner 的观点正确，部分原因可能是因为他们体型更大，因此需要更多空间。 ❚
本文节选自我们的订阅者时事通讯《我们的故事》(Our Human Story)，由科学作家 Michael Marshall 撰写。请在 newscientist.com/our-human-story 注册。
横向 7 基准 (8) 9 Joseph ___ ，英国植物学家，查尔斯·达尔文的朋友 (6) 10 建筑、木工等使用的 S 形设备 (4) 11 高度响应的肌肉纤维的术语 (4-6) 12 研磨工具 (6) 14 鳞甲目食蚁兽 (8) 15 蒸汽轮机组件 (7,6) 17 用于排液的柔性管 (8) 19 例如狮子或老虎 (6) 21 中国的食竹哺乳动物 (5,5) 22 简单的编程命令 (2,2) 23 积极的参与者、组件等 (6) 24 ___ 大道，布里克斯顿的一条干道，此前以其照明而闻名 (8)
6 2
2 4
纵向 1 花朵生殖器官的一部分 (6) 2 在单一场合 (4) 3 抗凝血药物 (8) 4 无质量粒子 (6) 5 与垂直方向呈 90 度 (10) 6 连锁 ___ ，自我增强的事件序列 (8) 8 消失的行为或实例 (13) 13 在飞燕草等植物中发现的毒性生物碱 (10) 15 旨在减少运动部件之间摩擦的组件 (8) 16 被炸毁的 (8) 18 键盘操作员 (6) 20 ___ 酸，HNO3 (6) 22 逻辑 ___ ，可能是 NOT、AND 或 NAND 的设备 (4)
区域
下周 隐喻填字游戏
由 Sam Wong 设题
1 化学式为 C5H9N3 的哪种化学物质能触发体内的免疫反应？
2 一种可用于破解当前加密标准的量子计算算法是以哪位研究员的名字命名的？他在 1994 年开发了该算法。
3 2003 年在东南亚的哪个岛屿上发现了小型古人类物种的化石？
4 地球第一个地质太古代的名称是什么？其持续时间从 4.6 billion 年前到 4 billion 年前。
5 哪位物理学家写了 1944 年的著作《What Is Life?》，书中思考道：“在生物体的空间边界内发生的时空事件，如何能用物理学和化学来解释？”
块状宇宙 由 Puzzlr 创建
目标是将下面的网格划分为不重叠的矩形。 每个矩形必须恰好包含一个数字，且其面积等于该数字。例如，数字 6 应位于一个覆盖六个方格的矩形中。
2 3 3
4 4 6 3
6 3
6 3 4
2 3 5 2
3 4 2 3
3 2
现在可通过在线方式游玩 newscientist.com/games
清新空气
新鲜空气是否比陈旧空气升温更快？如果是这样，原因是什么？
西蒙·李 (Simon Lee) 英国圣安德鲁斯大学 地球与环境科学学院 如果空气中含有较高浓度的二氧化碳（来自人类呼吸）和异味，它通常显得“陈旧”，但这两者都不会影响升温速度。然而，室内的陈旧空气通常（尽管并非总是）比室外的清新空气更潮湿。潮湿空气的热容比干燥空气略高，因此需要稍微多一点的能量来加热。但在实际操作中，这种差异小到无法察觉，尤其是室内外空气的湿度差异通常并不大。 通风可以改善空气循环，帮助散热器的热量分布更均匀。如果房间内形成了冷凝水，最初提供的许多热量将用于蒸发这些水分，而不是提高空气温度。使用干燥的室外空气通风有助于房间更快地干燥，从而使随后的
“ 当土壤干燥时，太阳能量中用于蒸发水分的部分较少，从而有更多能量用于加热地面和空气”
加热变得更有效。 在热浪期间也会发生类似的过程：当土壤干燥时，太阳能量中用于蒸发水分的部分较少，从而有更多能量用于加热地面和空气。
罗宾·马奎尔 (Robin Maguire) 澳大利亚塔斯马尼亚州霍巴特 我们可以将陈旧空气定义为被人类广泛呼吸过的空气。在这种情况下，它比清新空气含有更高比例的二氧化碳和水蒸气。 我们可以通过比较相关分子在恒压下的摩尔比热容——即增加特定体积温度 1 个单位所需能量的大小——来看这意味着什么。 氮气和氧气（构成了清新干燥空气 99% 以上的部分）的比热容均略高于 29 焦耳/克尔文/摩尔。二氧化碳和水蒸气（在常温常压下）的对应数值更高，分别约为 37 和 35 J/mol.K。 因此，陈旧空气的整体热容相当高于清新空气，所以假设能量输入速率固定，清新空气确实会比陈旧空气升温更快。
本周的新问题
干杯 调制鸡尾酒时最佳的冰块方式是什么：少量的几个大冰块，还是大量的几个小冰块？ 马克·哈珀 (Mark Harper)，英国布莱顿
就寝时间 需要睡眠的最小生物是什么，这能告诉我们关于睡眠本身性质和需求的什么信息？ 吉姆·麦克哈迪 (Jim McHardy)，英国西邓巴顿郡克莱德班克
想要向我们发送问题或答案？ 请发送邮件至 lastword@newscientist.com 问题应关于日常科学现象 完整条款和条件见 newscientist.com/lw-terms
然而，这种影响可能是很小的。如果某些清新空气的整体质量降级到相当于一次典型的呼气（在我看来这已经相当陈旧了），这将导致空气成分通过增加约 5% 的二氧化碳和也许 2% 的水蒸气（取决于初始湿度）而改变。这意味着整体热容仅增加 1 到 2%。 比热容随温度略有增加，分子越复杂增加越明显——例如二氧化碳相对于氮气。因此，随着温度升高，清新空气与陈旧空气之间的热容差异会略微增加。如果环境
保持鸡尾酒冰凉的最佳策略是什么：少量的几个大冰块，还是大量的小冰块？
温度从 0 到 30°C (32 到 86°F) 变化，热容差将增加约十分之一——不足以对情况产生重大影响。
有些蹊跷
大多数鱼类眼睛的位置意味着它们看不到自己的身体。那么，它们是如何识别同 species（同类）的呢？ (续)
ALEXANDER SPATARI/GETTY IMAGES
Shelby Temple 布里斯托大学，英国
人类，以及大多数动物也是如此，其眼睛固定在头部的方式使其无法看到自己的全身。蜗牛以及眼睛长在柄上的动物可能是例外。因此，同样的问题也适用于我们。
其中一部分是天生的，另一部分是习得的，就像人类婴儿看到父母的面孔并学会认出他们一样。我们还知道，对于某些物种来说，这种印刻效应（imprinting）是可以被欺骗的：这就是“行为学之父”康拉德·洛伦兹（Konrad Lorenz）如何成为刚孵化出的小鸭子和小鹅认定的父母的。
鱼类可能也没什么不同，它们可以为了各种好处而学会记住人们和面孔。我养的射手鱼学会了将我与我的妻子和其他客人们区分开来，因为我是唯一喂养它们的人。
所以，我认为能看到自己并不是认出同类物种的必要前提。考虑到对于某些鱼类来说，集群活动（staying in schools）的重要性，我怀疑它们利用了多种输入信息，包括视觉和嗅觉，加上关于安全与危险的学习经验。此外还有天生的认出能力，这在某些分布极其稀疏的鱼类中一定发挥了作用，例如深海鮟鱲，当雄鱼遇到配偶时，它们会附着在对方身上且永不分离。
Tom Gauld 为《新科学家 (杂志)》绘制
我怀疑在这种情况下，一只雄性深海鮟鱌鱼是否曾见过自己，甚至是否见过同类的其他个体，但它似乎仍然知道要将自己附着在雌鱼身上。在这种情况下，这几乎肯定取决于嗅觉线索，但在鱼类世界中，肯定还存在许多其他有趣且奇异的例子。
撞墙行为
当黄蜂、蜜蜂和苍蝇不断地撞击我温室的玻璃试图寻找逃生出口时，它们是在执行某种策略吗？（续前文）
Alan Harding 英国 伦敦 我认为之前对这个问题的回答忽略了苍蝇、黄蜂和蜜蜂之间的一个重要区别（4 July）。根据我的经验，黄蜂和蜜蜂会持续在窗户的同一个区域附近盘旋，而且非常容易捕捉——例如，用一个倒扣的玻璃杯将它们罩住，用一张纸盖住，然后通过打开的窗户将它们释放。
“向光而行曾让苍蝇获益， 但当面对玻璃——一项相对 近期的创新——时， 这种行为可能是致命且徒劳的”
而对于苍蝇，这几乎是不可能的，因为它们倾向于随机盘旋。我不认为这是一种逃生策略（如前所述，它们没有玻璃的概念），而更像是一种避免被吃掉的策略。蜜蜂和黄蜂有刺且身体有条纹，以此向捕食者发出“吃我的后果自负”的警告。我认为苍蝇随机的飞行路径是为了让捕食者更难捕捉并吃掉它们。
Jonathan Wallace 英国 纽卡斯尔-upon-Tyne 之前的通信员认为，苍蝇和蜜蜂为了逃离房间而撞击窗户的行为并没有遵循任何特定策略。这可能是错误的。如果你观察一只在房间里移动的苍蝇，你不会看到它像撞击窗户玻璃那样反复地撞击墙壁。这表明苍蝇（或蜜蜂）显然将窗户“视为”出口。 飞行昆虫不会像我们那样通过推理来寻找离开房间的方法，但它们很可能演化出了一种在黑暗空间内本能地向光线方向飞行的策略。在大多数情况下，这种简单的策略对它们很有效，但当面对玻璃——这在苍蝇的进化史上是一项非常近期的创新——时，该策略就变得潜在且致命地徒劳。
Garry Trethewey 南澳大利亚州 阿卡鲁拉 是的。策略就是“向光而行”。在没有窗户的数百万年里，这对它们一直有效。现在，失效了。 ❚
答案
纵向 1 Stigma, 2 Once, 3 Warfarin, 4 Photon, 5 Horizontal, 6 Reaction, 8 Disappearance, 13 Delphinine, 15 Bearings, 16 Inflated, 18 Typist, 20 Nitric, 22 Gate
横向 7 Standard, 9 Hooker, 10 Ogee, 11 Fast-twitch, 12 Sander, 14 Pangolin, 15 Balance piston, 17 Catheter, 19 Feline, 21 Giant panda, 22 Go to, 23 Agents, 24 Electric
快速填字游戏
5 Erwin Schrödinger
4 Hadean
3 Flores
2 Peter Shor
1 Histamine
快速问答 #362
Block Universe 解答
坚硬的土地
当你开始看电影时，有些角色你可以自信地预言他们一定会死。一个陪同两个主角参加动作场面的次要角色？死掉用以展示赌注之高。史诗奇幻故事中睿智的老导师？肯定在第二幕结束时死去。读者反馈 (Feedback) 栏目了解这些陈词滥调以及更多，但之前我们从未想到过地质学家也处于危险之中。然而，事实证明，他们的预期寿命仅比肖恩·宾 (Sean Bean) 饰演的角色好那么一点点。我们是从《今日地质》(Geology Today) 的一项有趣分析中得知这一点的。瑞典哥德堡大学的地质学家埃里克·斯图克尔 (Erik Sturkell) 及其同事在过去十年左右的时间里，通过收集电影中地质学家的例子来自娱自乐：他们是谁，如何被塑造，以及他们往往会面临怎样的结局？斯图克尔的团队目前记录了“141 部电影，涵盖 1919–2023 年期间，其中出现了 202 位地质学家”。事实证明，地质学家大多出现在以冒险、剧情、动作和科学幻想为中心的电影中。研究人员写道：“地质学家电影很少是喜剧。” 电影地质学家中只有 11% 是女性，不过这在 1990 年代以来显然有所提升。此外，电影中的地质学家即便不总是英雄，但“至少没有犯下任何职业不端行为”。然而，他们却经常被除掉。作者写道：“地质学家在电影中的死亡率高得惊人，而且通常死得很早。” 根据年代的不同，死亡率在 31.6% 到 35.7% 之间波动。在 202 位地质学家中，有 69 人死亡，其中 30 人死于谋杀。作者引用了 1967 年的电影《金钱丛林》(The Money Jungle) ——读者反馈栏目没看过这部片子，但其中涉及多家石油公司为了控制一个富矿而密谋。在这场不堪的争吵中，五名地质学家被谋杀，且手段极其多样，“例如被高尔夫球车电击、在服药时被下毒、在壁炉旁被毒气杀害，以及在玩具火车爆炸时被杀”。作者指出，这是“任何电影中地质学家最严重的连环屠杀”。
在这些年间，另有 12 位地质学家死于“与工作相关”的原因，例如“被火山弹击中、掉进火山口或开口断层、淹死在流沙或火山泥流中，以及在油坑中被焚毁”。同样常见的是涉及外星人的死亡，例如在《普罗米修斯》(Prometheus) 中被外星人同化，并“随之被前同事杀死”的地质学家。
这一切都非常迷人，但读者反馈栏目发现自己被后续问题困扰了。其他科学分支的电影死亡率又是多少？我们不禁怀疑，古生物学家的处境一定极其糟糕，因为他们只出现在那些灭绝生物复活并开始吃人的故事中。另一方面，电影里的固态物理学家日子可能过得相当惬意。有人能给我们指路一个数据集吗？
[[IMG_Twisteddoodles]] 为《新科学家 (杂志)》创作的 Twisteddoodles
有故事想告诉读者反馈 (Feedback) 吗？ 请发送至 feedback@newscientist.com 或寄至 New Scientist, 9 Derry Street, London, W8 5HY 邮寄项目处理时间较长
我，我，我
读者反馈 (Feedback) 惊恐地发现，在过去的几十年里，流行音乐的歌词变得明显更加以自我为中心。根据《PLoS One》的一项研究，这在美国和德国确实如此。该研究调查了从 1970 年到 2019 年每年最受欢迎的 10 首歌曲。分析显示，与“我们”和“我们的”等第一人称复数词相比，“我”、“我”和“我的”等第一人称单数词的使用量有所增加。奇怪的是，这种情况在日语和香港地区并没有出现，研究表明
将其描述为“更具集体主义色彩”。该论文以近乎末世的措辞处理这一问题，指出“当代社会日益以自我为中心，这反映在贪婪、自恋和社会疏离的程度上”。
《反馈》(Feedback) 栏目当然不会发起一场“贪婪是好事”的辩护，但我们确实有疑问。首先，这一趋势在很大程度上是由极具企业家精神的美国驱动的，还是由资本主义程度相对温和的德国驱动的？其次，“我”这个词的增加在多大程度上可以用独唱艺术家的崛起和乐队的全面崩塌来解释？K-pop 团体——此时基本上是唯一幸存的成功乐队——是否也表现出这种自恋倾向？
她会回来的
上个月，《新科学家 (杂志)》评述了《我们不是机器：争取工作的未来》(We Are Not Machines: The fight for the future of work) 一书，该书认为人工智能并非正是要来抢走我们的工作，而是我们的工作正在被扭曲以适应人工智能（6月 20 日，第 24 页）。结果是，曾经有趣的工作变得枯燥，公司的产品和服务也变得越来越糟。
读者 Ian Williams 和 Erik Foxcroft 都联系了我们，指出一个令人不安的近乎巧合：该书作者，一名《金融时报》(Financial Times) 的记者，名叫 Sarah O’Connor。“哦，简直太完美了，”Erik 说。
拥有一个几乎与《终结者》(The Terminator) 中人类主角完全相同但又略有差别的名字，此前曾引起过波澜。2015 年，O’Connor 是《金融时报》的就业记者，她发推特称：“一名机器人杀死了德国大众汽车工厂的一名工人。”这条看似“赛博格杀人”的新闻与 O’Connor 的名字结合在一起，在网络上疯传。讽刺的是，她当时从未看过这部电影，也没听懂这个梗。《反馈》假设她此后已经观看了该片，并希望她在书的结尾写下三个词，承诺会有续集。 ❚
28 Reality’s missing ingredient A strange particle that is neither matter nor energy could finally reveal how the universe works
11 AI arms race Why has alarm over powerful AI models built by Chinese companies waned?
12 Metallic bite Sea worm uses “bio-metal” jaws to crush its prey
13 Mummified warriors Ancient Egyptian princesses wielded weapons
18 Sneaky maths Jacob Aron explores a trick for solving problems without answering them
20 Virtual particles Chanda Prescod-Weinstein on weird glue-like particles
22 Aperture Haunting sculpture shines light on sea-level rise
24 Book of the week An intriguing book reveals sunlight’s health-giving effects
27 Letters Thoughts on the fastest spider
cover
Vol 271 No 3605 Cover image: Stephan Schmitz
6 Quantum consciousness New maths on an old problem
37 What we can learn from the happiest country in the world
32 Is unlimited geothermal power within reach?
4 Exoplanet shows promise in hunt for alien life
9 Invisible drone
7 Stone-Age fish farmers
13 Weird-smelling monkey
is really well
placed to be
the glue that
will make
low-carbon
electricity
systems
work”
28 Reality’s missing piece
A weird third type of
particle could explain
reality at its deepest level
32 Deep heat We may finally be able to use geothermal practically anywhere
37 The secrets to happiness What we can learn from the nations where people feel the most content
40 On the smaller side Our ancestors were shorter than we often depict them
43 Puzzles Try our crossword, puzzle and quiz
46 Almost the last word Does fresh air heat up faster than stale air?
48 Feedback Investigating the life expectancy of geologists on screen
ANNIE OTZEN/GETTY IMAGES
48 Twisteddoodles
for New Scientist
Picturing the lighter side of life
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as New Scientist has reported, cheap consumer drone technology is helping Ukraine hold back the invasion. But while many readers may cheer on Ukraine’s fight, the fact that anyone can now download a cruise-missile guidance system should give us a moment’s pause.
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behind the US models in capability – but anyone with the necessary hardware can download and run them for free. While the closed US models generally come with guardrails to prevent chatbots from spewing out harmful material, open- source models have fewer such limits and the ones that exist are easier to remove. That creates headaches for attempts to regulate AI models, such as testing them for national security risks before release, as was recently suggested by Google DeepMind CEO Demis Hassabis. But it also offers the opportunity for more people to find ways of using AI models that US tech firms may not have thought of. Open source means problems can be shared – it’s just that some will get easier to solve, while others get much harder. ❚
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The right atmosphere for life?
zone is the most promising lead yet in our hunt for alien life, reports Leah Crane
FOR the first time, astronomers have detected an atmosphere on a rocky, temperate world beyond our solar system. It is the strongest evidence yet for an exoplanet that could be able to support alien life. The planet in question, called LHS 1140b, orbits a small, cool type of star called an M dwarf, about 50 light years from Earth. Researchers have been searching for atmosphere-shrouded planets around M dwarfs for decades because they are the most common type of star in the galaxy, but with no luck until now – some researchers had even postulated that planets around these small stars might not be able to hold onto atmospheres. But when Collin Cherubim at Harvard University and his colleagues observed LHS 1140b in 2024 at the Las Campanas
Complex sugars found in interstellar space
While detecting an atmosphere on an exoplanet hints that other worlds may have conditions that can support life (see main story), the discovery of complex sugar molecules in interstellar space suggests how the building blocks of life may have spread around the galaxy. Certain sugars are fundamental building blocks of RNA and DNA, the genetic material found in every living cell. Recent discoveries of sugars in meteorite and asteroid samples suggest that such bodies may have delivered them to the young Earth. Izaskun Jiménez-Serra at the Centre for Astrobiology in Madrid, and her colleagues wondered if sugars might be present in interstellar space itself. To find out, they aimed radio telescopes at G+0.693−0.027,
Observatory in Chile, they found a promising signal: a line in the spectrum of the planet’s light indicating helium atoms in an excited energy state. There are several possible explanations for this, but the shape and strength of the signal led them to conclude that the helium was part of an outflow, leaking away from a planetary atmosphere (Science, doi.org/hcbwhf). “By far the most simple explanation is that this helium that we see is from the planet itself,” says Cherubim. This would put LHS 1140b in the category of helium worlds, a type of exoplanet that has been proposed but not definitively detected. “It’s different from what we would expect given the rocky planets in our own solar system,” says Natalie Allen at Johns Hopkins University in Maryland.
a large molecular cloud 26,700 light years away that is known to contain dozens of organic molecules, including glycolaldehyde, a compound involved in sugar formation but not considered a true sugar itself. The team compared the cloud’s radio emissions with laboratory measurements of spectral fingerprints – distinctive patterns of radio frequencies that molecules absorb and emit – for the simplest sugars, glyceraldehyde and dihydroxyacetone. When results came up empty for either of these three-carbon sugars, Jiménez-Serra says she decided to check for a four-carbon sugar, erythrulose, one of the sugars found in raspberries. To her surprise, the team found an incredibly rich supply of the molecule
LHS 1140b, seen here in an artist’s impression, orbits an M-dwarf star
(Nature Astronomy, doi.org/rf25).
“These molecular clouds
are basically the birth sites
of stars and planets,” she says.
“So essentially, we’re finding that
these complex organic compounds
that are important for the origin
of life can form already very
early in the formation process
of a planetary system.”
Chemistry unlike anything
naturally seen on Earth – playing
out on icy dust grains chilled to
around -250°C and bombarded
by intense radiation – may have
produced some of the molecular
building blocks that ultimately
gave rise to life, says Niels
Ligterink at TU Delft in the
Netherlands. “We can now
say that the ingredients for
biochemistry are likely spread
throughout the galaxy,” he says.
Christa Lesté-Lasserre
In some ways, a helium world could be more similar to a gas giant than any of the terrestrial worlds in our solar system, with a thick, heavy atmosphere overlaying a rocky or icy surface. “It’s exciting on its own merits, not as a new Earth,” says Sukrit Ranjan at the University of Arizona. “It might be habitable, but not in a conventional sense.” If it does have a thick atmosphere, pressures at the surface could be similar to those at the bottom
“ This planet has now become the best place to search for life outside of our solar system”
of Earth’s ocean. If not, it could potentially be an ocean world more similar to icy moons in our solar system than any of the planets. Right now, we know this world has an atmosphere that seems to be leaking helium, but we know very little about the size and composition of the atmosphere itself. “Earth and Venus are very similar in size and both have atmospheres, but Venus’s surface isn’t habitable,” says Allen. “I think to have a real picture of habitability
MELISSA WEISS/CENTER FOR ASTROPHYSICS/HARVARD & SMITHSONIAN
on this planet, we need to understand the bulk atmosphere.” As-yet-unpublished data from the James Webb Space Telescope could help clear that up, she says.
Missing signature
However, the very presence of an atmosphere, along with the fact that LHS 1140b orbits its star in what is known as the habitable zone, where temperatures are mild enough to preserve liquid water on its surface, makes it extremely promising. “This planet has now become the best place to search for life outside of our solar system,” says Cherubim. There is a caveat: when Cherubim and his colleagues observed LHS 1140b again with the same set-up in 2025, they didn’t see the signature helium line. They pored over the 2024 and 2025 data, consulted with other researchers and had a separate team reanalyse the data, and the results remained the same: the excited helium was there in 2024, and not in 2025. That was surprising, but not altogether abnormal, says Cherubim. “When you make a measurement of escaping helium and then you go back and look at it months and years later, it is usually different and sometimes it isn’t there – and we don’t understand it,” he says. This particular helium signature is poorly understood, says Ranjan, so we can’t be sure why it might have appeared and then disappeared. It is possible that the shape of the outflow changed, or that stellar activity shifted the nature of the helium in the outflow. If the helium is still there but not in an excited state, we would expect the signature to disappear. Cherubim has plans to continue observing LHS 1140b in an attempt to figure it out. ❚
Neuroscience
after brain stimulation ended
Christa Lesté-Lasserre
A MAN who became paralysed after a diving accident six years ago regained the ability to move and feel pressure in his hands thanks to brain stimulation. Now, researchers have revealed he maintained this ability for months after the stimulation was switched off. “We turned everything off completely, for many months, and yet he’s maintained these gains,” says Chad Bouton at the Feinstein Institutes for Medical Research in New York. “That’s unheard of.” Keith Thomas, 48, was paralysed from the chest down in July 2020. He had no sensation or control over his limbs and had significant muscle wasting, says Bouton. In 2023, Bouton and his colleagues performed a double neural bypass surgery on Thomas, placing five electrodes into his brain in regions associated with arm movements and feeling. They connected computer cables to these electrodes, so
FEINSTEIN INSTITUTES FOR MEDICAL RESEARCH
“ We turned everything off completely, for many months, and yet he’s maintained these gains”
Keith Thomas shaking hands with Chad Bouton
artificial intelligence could interpret his movement intentions. That information was then wired into electronic splints that stimulated his arms, hands and fingers to carry out his intended movements, enabling him to pick up coffee cups and scratch his face. To recreate the sense of feeling, the team embedded force sensors into 3D-printed
wearable devices for Thomas’s hands and fingers, which sent feedback via electrical stimulation into the brain’s sensory areas. After conducting a series of experiments, Bouton says the team planned to stop the stimulation for about a month, to test for any lingering effects. “Then we had a fire in the building, and it actually forced us to stop stimulation for even longer than we’d planned, for about three months,” he says. The unexpected interruption led to surprising findings:
Thomas continued to maintain strength, feeling and function in his hands (Nature Medicine, doi.org/hcbwnc). “He’s now also controlling individual fingers with even more accuracy, so that’s big,” says Bouton. In a video interview with New Scientist, Thomas raised his elbows nearly to shoulder level and described feeling “tingling” in his wrist in response to pressure, even when he is “unplugged from the computer”. “When I first felt it, it was amazing,” he says. “I’m used to it now.” Sergey Stavisky at the University of California, Davis, says the work suggests that this approach promotes lasting recovery of the nervous system. “The goal is to help the nervous system partially heal so the person can move their own body better,” he says. “If these improvements persist even when the system is turned off, then the device is doing more than temporarily restoring function,” says Daniel Lu at the University of California, Los Angeles. “It may be helping the nervous system reorganise itself through neuroplasticity.” This describes the brain’s ability to rewire itself by forming new neural connections, such as after an injury or even in response to a new hobby. But this is just a single case report, so it is unclear how well this approach would work on other people with paralysis from different types of injuries. “This is a really ambitious study, but we need to see them replicating their results in more participants,” says Charles Greenspon at the University of Chicago. ❚
Physics
quantum nature of consciousness to bed, asks Karmela Padavic-Callaghan
THE controversial idea that consciousness has a quantum origin is facing a new challenge, after a mathematical analysis appears to show that a long-known law of physics makes it impossible. What physical process makes us conscious, and whether we could observe and analyse it, is one of the great open questions of modern science. In the 1990s, mathematician Roger Penrose and anesthesiologist Stuart Hameroff proposed that classical physics can’t explain consciousness alone, and so it must arise in the quantum realm. The idea was received with scepticism and remains controversial, but attempts to bring quantumness into explanations of consciousness have persisted since. Now, Emily Adlam at Chapman University in California and her colleagues have examined the idea of purely quantum agency, which is a prerequisite for consciousness, and found it doesn’t work. Consciousness is notoriously hard to define, but the team formulated a minimal definition of agency using clear physical requirements. Quantum theories of consciousness, even if they focus on specific mechanisms in the brain, like in Penrose and Hameroff’s proposal, ought to be compatible with this definition if they are to be plausible. Specifically, the researchers focused on a model of an agent that observes the world, creates a model of it, then uses that model to evaluate outcomes of different possible actions before deciding on performing one. “There will be a step in terms of taking information out of the environment that you’re going to respond to, and then some kind of [information] copying
Quantum agency
The quantum nature of consciousness has been debated since the 1990s
steps, so that you can consider different possible options, and then at the end, a comparison step where you look at the outputs of each of your models, decide which is the best and use that to guide your actions,” says Adlam. But if the agent is quantum – so must behave according to the laws of quantum mechanics – the copying step is impossible. This is because of the “no-
“ It is more likely that these phenomena arise from, or are at least dominated by, classical mechanisms”
cloning theorem”, which says that quantum states that describe all information about a system can’t be copied or duplicated. Adlam says that an agent may try to deal with this by creating imperfect copies of information it needs to deliberate instead, but other problems then arise. For example, extracting quantum information from the world changes it, so the agent’s world model actually reflects a slightly
YANA ISKAYEVA/GETTY IMAGES
different world. While some level of imperfection is always present in how we model the world, these faults would compound. The comparison step also suffers from quantum weirdness. Adlam says that this is because the purely quantum agent could only use quantum information processing, which makes available different processes than we are used to. “A realistic quantum operation is going to end up doing some kind of funny superposition of all of the possible options, weighted towards the better ones. You don’t actually implement the best option, you do this weird combination of all of them,” she says. These conclusions challenge quantum theories of agency, free will and consciousness, as well as impose technological constraints on any agents that quantum computers may be able to simulate in the future, said team member Kelvin McQueen, also at Chapman University, in a presentation at the Foundations of Physics conference in Irvine, California, on 17 June. “These results help us understand
how agency and human- like perception can emerge in an otherwise quantum mechanical universe,” he said.
In fact, the problems with a purely quantum agent that the researchers identified make it harder to justify an essentially quantum mechanism for both agency and consciousness. It is much more likely that these phenomena arise from, or are at least dominated by, classical mechanisms, says Adlam. “There could be some circumstances where perhaps doing a quantum calculation gives you a speed-up, but certainly it makes the whole process of agency look like it is basically founded in the classical regime,” she says. Because quantum physics is the best physical theory that we have, it makes sense for us to ask what agency looks like from that perspective, says Sally Shrapnel at the University of Queensland in Australia. The researchers’ model of agency is informed by a specific interpretation of what is essentially real in the quantum world, she says. If quantum states are seen not as idealised building blocks of reality, but rather objects that reflect our knowledge of the world, then a quantum model of agency could be less constraining, she says. For example, an agent could be modelled as constantly interacting with an environment and dynamically converging on a decision instead of deliberating between world models, which would allow for a mixture of classical and quantum information processing. Existing theories of quantum consciousness aren’t as rigidly quantum as the new study’s model, so they may not be fully off the table just yet, says Shrapnel. ❚
Ageing
zombie cells may improve ageing
Isha Ishtiaq
AS WE age, our body loses its ability to clear out zombie-like cells that have stopped dividing, instead dripping out poison and turning other cells rogue. Restoring the ability to remove these “senescent” cells prevented signs of cognitive decline and frailty in older mice, with hints that the same outcomes could occur in people. Katrin Andreasson at Stanford University, California, and her team compared mice aged 6 to 8 months (roughly equivalent to people in their 20s) with mice aged 23 to 25 months (equivalent to people in their late 60s or 70s). They found that the older mice had more of these senescent cells in their organs, including the liver and spleen, and in their bone marrow. The senescent cells were neutrophils, immune cells that are normally the body’s first line of defence against infection. These would usually be cleared by cells called macrophages residing in tissue, which remove damaged cells and debris, but this ability declines with age. Andreasson and her colleagues traced this decline
Older mice had more zombie immune cells in their spleens
ROSSANA MELO/SCIENCE PHOTO LIBRARY
to prostaglandin E2, a signalling molecule that increases with age. They found that higher prostaglandin E2 activity overstimulates a receptor called EP2 on tissue-resident macrophages, which leaves them less able to remove senescent cells. Next, the team tested whether blocking this overstimulation could improve signs of ageing by genetically modifying the EP2 gene from tissue-resident macrophages in older mice. These animals went on to clear more senescent neutrophils and showed signs of healthier ageing, including lower levels of inflammation, reduced muscle loss and better mobility, compared with
“ Restoring the ability to remove zombie cells prevented signs of cognitive decline”
unmodified mice of the same age. They also performed almost as well as young mice in memory tests. The researchers also tested an experimental drug that blocks the EP2 receptor protein. When given orally to older mice for two months, this caused similar age-related improvements to those in the genetically modified mice (Science, doi.org/rgfp). Finally, the team found similar patterns in human tissue, with liver samples from older people showing higher EP2 receptor activity and more senescent neutrophils. “The human data are supportive, but still correlative,” says Derek Gilroy at University College London. “We haven’t yet shown that blocking [the EP2 receptor] can restore neutrophil clearance in aged human tissue.” ❚
Archaeology
found in Norway
James Woodford
MAGNE SAMDAL, MUSEUM OF CULTURAL HISTORY, UNIVERSITY OF OSLO
HUNTER-GATHERERS transported brown trout into the mountains of Norway at least 7000 years ago so they could be harvested during summer trips into the highlands. That is the only explanation for how fish could have populated isolated mountain lakes that had been covered by a kilometres-thick ice sheet for tens of thousands of years, says Axel Mjærum at the University of Oslo, Norway. “This is the oldest documented example of human-mediated translocation of fish in the world,” he says. Until around 8400 years ago, Lake Tesse, at an elevation of around 850 metres, was covered by the Fennoscandian ice sheet, leaving an ecological blank canvas once it retreated. Yet, until the 1940s, Lake Tesse was regarded as one of the richest brown trout waterways in Norway, yielding 9 tonnes of the fish a year. While it has long been suspected that humans had a hand in establishing the brown trout population in Lake Tesse, we had no idea when this happened. Mjærum and his colleagues studied the partially buried remains of elaborate wooden fish traps, discovered in 2022
Before farming started in Norway, people made fish farms in Lake Tesse
when the lake level was lowered. Radiocarbon dating showed that the oldest trap dated from around 4950 BC. By correlating the recovered wood with pine tree ring chronology, the team was able to precisely date some of the posts that were part of the younger traps. One came from a tree felled between spring 2669 BC and winter 2669-2668 BC, and another 12 years later during the winter of 2657-2656 BC, demonstrating that the traps must have been maintained to keep them in good working order (Antiquity, doi.org/rgfq). “It is possible that this form of trap fishing was ongoing in Tesse during much of the period between 5000 and 2650 BC,” says Mjærum. The transport of fish into the lakes is an early example of people managing the environment to provide food, centuries before the advent of farming in Scandinavia. How people moved the fish is unknown, but they may have used waterskins. People probably then stayed in the mountains for part of the summer, hunting reindeer and fishing, says Mjærum. ❚
Health
treat multiple sclerosis
Michael Le Page
THE best therapy for multiple sclerosis (MS) might be antivirals that target the Epstein-Barr virus. “There aren’t good Epstein- Barr virus drugs currently available, but they can be developed,” says Michael Levy at Harvard Medical School. “That might be the most useful specific therapy for MS in the future.” MS is caused by an immune attack on myelin, a fatty sleeve that wraps around nerves. The loss of myelin reduces nerves’ ability to transmit signals and can cause a wide range of symptoms, including muscle weakness. Drugs that suppress the immune system can slow the progression of the condition. There is strong evidence that the Epstein-Barr virus (EBV), which causes mononucleosis, or glandular fever, is also the cause of MS. But exactly how remains a mystery. Almost everyone is infected with EBV before adulthood. It mainly infects immune cells
In MS, some brain immune cells attack nerve cells
PROFESSOR JOHN ZAJICEK/SCIENCE PHOTO LIBRARY
called B-cells, where it can lie dormant for the rest of a person’s life. But in some cells, the virus can reactivate. The big question is why only around 1 in 1000 people develop MS when nearly everyone gets EBV. This suggests there is something different about the immune response to EBV in people who go on to develop MS, says Natalia Drosu at Massachusetts General Hospital. In a new study, Drosu and her colleagues focused on immune cells that circulate in the body called CD4 T-cells. These cells don’t directly attack myelin, but they seem to play a role in MS, says Drosu. They found that, in 30 people with MS, most of the CD4 T-cells targeting EBV were specifically targeting viral proteins produced when the virus is actively replicating, rather than the proteins linked with its dormant stage. People with MS also produced twice as many of these cells, on average, as 30 people without the condition. The researchers then looked at the T-cells in 60 people
with MS before and after they began drug treatments that lowered their B-cell numbers. They found these treatments reduced the T-cell response to EBV almost to the levels seen in people without MS. The team also found low levels of EBV in the saliva of these people before they were treated,
“ Epstein-Barr virus drugs might be the most useful specific therapy for MS in the future”
which shows that the virus was replicating in their bodies. After treatment, viral levels dropped below detectable levels in most people (Science Translational Medicine, doi.org/rf2t). The thinking has been that B-cells help drive the harmful immune response in people with MS, says Levy, and this is why drugs that reduce B-cell levels work. But the results suggest these drugs also work by eliminating EBV-infected B-cells, he says, thereby reducing the immune response caused by active viral replication. “We’re thinking that depleting B-cells is also depleting the reservoir of the Epstein-Barr virus.” If so, targeting EBV directly with antivirals might be just as effective as B-cell-depleting drugs, but without the undesirable side effects of treatments that weaken the immune system, such as an increased risk of infections. “I think a lot of patients would prefer a specific drug,” says team member Kjetil Bjornevik at the Harvard T.H. Chan School of Public Health. “If we can show that an antiviral had a similar effect as the most effective MS drugs, I think there will be a big market for that drug.” ❚
Oral health
linked to gum irritation
Mattha Busby
NICOTINE pouches probably cause receding gums, as well as discomfort and redness. That’s according to the first study investigating their effects on the lining of the mouth relative to snus, which is generally considered more harmful to use because it contains tobacco. Tobacco-free nicotine pouches have surged in popularity in recent years. The small sachets fit under the top lip, similar to snus, a powdered tobacco that is sometimes administered in a pouch. Snus has been linked to mouth irritation and heart-related deaths, but less is known about nicotine pouches. Now, Karin Legert at the Karolinska Institute in Sweden and her colleagues have studied 272 adults, aged 18 to 30, of whom 126 used nicotine pouches and 63 used snus. They used their product five or more times a day for at least three months, but didn’t use any other nicotine or tobacco products. The researchers also looked at 83 people who didn’t use nicotine pouches, snus or any related products. They observed gum recession – which exposes the teeth’s sensitive roots – in 45 per cent of the nicotine pouch users, 52 per cent of the snus users and 6 per cent of the non- users. This recession often occurred around the area where users typically placed their pouches or snus (Oral Diseases, doi.org/hb959h). The researchers also found that nicotine pouches seem to cause more gum irritation, such as redness and discomfort, than snus. This could be because they are often flavoured, which “may contribute to irritation, epithelial damage and inflammatory responses, especially in sensitive oral tissues”, says Legert. The users’ favourite flavours were minty, which often consist of “complex mixtures of chemical constituents, as well as synthetic cooling agents”, says Legert. ❚
Technology
highlighting how consumer tech is helping to reduce weapons costs, reports David Hambling
UKRAINE has developed a cheap
cruise missile guided by an open-
source autopilot system typically
found in consumer drones.
The use of hobby components
highlights the shrinking gap
between military and consumer
electronics, which may make it
easier for small countries and
non-state actors to develop
powerful high-tech weapons.
With foreign long-range
weapons hard to come by, Ukraine
has had to develop its own. Fire
Point, a Ukrainian company,
showed off its FP-5 Flamingo
cruise missile at the Eurosatory
defence expo in Paris last month.
The 6-tonne missile can carry
a warhead twice as heavy as a
Tomahawk cruise missile for
twice the distance, but costs
a fraction as much.
One secret of Flamingo’s
low cost is its Ardupilot flight
controller, which uses sensor data
to keep the missile flying stably
along its assigned path. Ardupilot
is an open-source software suite
that has been around since 2009,
and can run on hardware costing
less than $100. Drone hobbyists
use Ardupilot on everything from
multicopters and model aircraft
to boats and ground vehicles.
FIRE POINT
Stealth drone spins so fast it disappears
As hobby drone components work their way into larger cruise missiles (see main story), a new drone has been created that avoids detection in an unusual way: spinning so fast that it blurs into the background. The drone, known as Phantom Twist, was created by Emma Alexander and her colleagues at Northwestern University in Illinois. It spins at 25 revolutions a second to hide itself in a motion blur like the blades of a fan. But unlike a
“ Small countries can now make weapons almost as capable as those of their well-funded neighbours”
In a post on X, Fire Point’s Chief Technology Officer Iryna Terekh said open-source software offers independence because it doesn’t come from a company that may go out of business or be blocked from exporting to Ukraine. What’s more, a community of thousands of engineers quickly finds and
fan, which has fixed parts that remain visible, every single part of Phantom Twist whirs in circles. “The motion blur essentially turns all of the mechanical components into this slight haze,” says Alexander. “And if you’re not paying attention, you might really miss that slight change in the brightness of the environment.” The single-motor design was chosen through an automated process involving three AI models.
resolves bugs in the software. “The use of open-source Ardupilot is in keeping with Fire Point’s whole philosophy of rapidly providing effective long- range strike at a vastly lower cost than exquisite Western designs,” says Roy Gardiner at the non-profit group Defense Tech for Ukraine. Gardiner notes that Ardupilot is one the world’s most extensively tested autopilots. Ukraine’s fleet of small drones, many derived from hobby designs, runs largely on
The researchers stepped in at the
end to build the best, final design.
That winning design spread
the components around so that
none visually overlapped when
spinning. The drone is small
enough to fit in the palm of the
hand and weighs just 30 grams.
The researchers presented
their work at the Robotics:
Science and Systems conference
in Sydney, Australia, last week.
Matthew Sparkes
Simulated image of the FP-5 Flamingo cruise missile
open-source flight controllers
such as Ardupilot.
Russia is also relying heavily
on commercial electronics in its
Shahed attack drones, according
to Ukrainian drone expert Serhii
Beskrestnov. While earlier
versions navigated by satellite,
a new “Seeker” version has
a camera and Raspberry Pi 4
processor with AI software to lock
on to targets, Beskrestnov said on
Telegram. The Raspberry Pi, made
in the UK, is used in educational
and hobby computing projects.
The software on the Shahed
hasn’t been identified, but smaller
drones often use Raspberry Pi with
open-source vision software called
YOLO for locking on to targets.
Ukraine has also deployed the
more conventional Storm Shadow
cruise missiles developed by
French and British companies,
while Russia has its own high-
end Kalibr cruise missiles.
But given the rapid
improvement in commercial
hardware and open-source
software, it is unclear how well
these legacy systems, with their
high costs but arguably superior
performance, can compete in the
long run. “Over time, expensive
custom military electronics and
software will likely be developed
only for the most demanding
requirements,” says Gardiner.
Now, small countries can
make weapons almost as capable
as those of their large, well-funded
neighbours, and non-state actors
can make their own cruise
missiles. “The dramatic reduction
in cost gives many state and
non-state actors access to strike
capabilities that were previously
available only to the wealthiest
nations,” says Gardiner. ❚
Climate change
but this trend is expected to reverse, discovers Alec Luhn
AN INCREASE in low-lying clouds has been shading the ocean and cooling the planet. But this feedback may now be reversing, which could accelerate global warming. Clouds have been the biggest wild card in our efforts to predict future climate change, as they reflect radiation in ways that can both warm and cool the world. Wispy cirrus clouds in the upper troposphere don’t reflect much incoming sunlight, and they trap outgoing heat. Thick blankets of stratocumulus clouds in the lower troposphere, on the other hand, reflect sunlight away from Earth, which is why geoengineering researchers have been spraying tiny droplets of seawater to try to make them even more reflective. Climate models project that, as the world warms, fewer low clouds will form to block sunlight. That could kick off a positive feedback loop towards more warming, leading to even fewer low clouds. But satellite data hasn’t been consistent enough to tell if low clouds are increasing or decreasing, especially in the south-east Pacific and Atlantic oceans, where the largest, longest- lasting cloud decks tend to form. Now, Gregory Cesana and Assia Arouf, both at Columbia University in New York, have estimated low cloud cover going back to the start of the satellite era in 1979 for the first time. The pair essentially correlated data on sea-surface temperature, wind speed and atmospheric stability with the low cloud cover measured by modern satellite instruments, then used this data to calculate low cloud cover in previous decades when satellite measurements were poorer. They found that low cloud cover has been expanding, increasing the energy reflected from Earth’s
JIM CORWIN/ALAMY
Low-lying lumps of stratocumulus clouds help to cool the planet
“ If that trend reverses as expected, it could ‘unmask’ warming and further accelerate climate change”
surface by 0.32 watts per square metre since 1979. For comparison, human-caused climate change is now heating Earth by about 2.72 watts per square metre. That means low clouds have shaved a fraction off global temperature rise, although it is difficult to say exactly how much. “We get a negative feedback, so the clouds are actually opposing the warming,” says Cesana. “And this is completely different from what you get when you look at those idealised experiments using the climate models.” In tropical areas like the eastern Pacific, low cloud cover has been increasing by 0.18 per cent per decade, the researchers found (Geophysical Research Letters, doi.org/rgfv). That is because the eastern Pacific has been warming less than many models expected, while the western Pacific has heated up strongly. As a result, the surface air over the eastern Pacific has remained cool, while atmospheric circulation has
brought increasingly warm air from the western Pacific down on top of it. The resulting temperature inversion prevents the warm, dry, sinking air from mixing with low stratocumulus clouds. “That’s going to favour the creation of low clouds or make them more stable so they can last longer,” says Cesana.
Storm clouds are gathering
But scientists expect the eastern Pacific will soon start heating up, in part because of stricter controls on sulphur pollution, which forms clouds that cool the planet and influence atmospheric and ocean circulation. That would allow the warm, sinking air to dry up some of these low clouds. This may already be happening. In March, Paulo Ceppi at Imperial College London and his colleagues found that low cloud cover has decreased globally since 2003, and a 2024 study said that the recent acceleration in global warming may be partly due to an emerging positive feedback effect of low clouds. “There’s no reason to think that we are overestimating the impacts of future climate change,” says Ceppi. “If anything, we might be slightly underestimating the effects of future climate change because of this amplifying effect of clouds on global warming.” The finding that low cloud cover had been expanding could actually be bad news, says Cesana, because if that trend reverses as expected, it could “unmask” warming and further accelerate climate change. Planet-warming El Niño events, like the one now developing in the eastern Pacific, diminish low clouds, “so we’re going to have a taste of what could happen in the future,” he says. ❚
Analysis Artificial intelligence
Why has alarm over powerful artificial intelligence models built by Chinese companies waned, asks Matthew Sparkes
WHEN Chinese company DeepSeek released its open-source R1 model in January 2025, it made headlines around the world. The large language model (LLM) was reported to rival some of the most powerful AIs from US companies, but it was free for anyone to download. A trillion dollars was wiped off the value of US tech companies, and US lawmakers immediately proposed banning it on government devices. When another Chinese firm, Z.ai, released GLM-5.2 last month, there were similar claims about performance but, surprisingly, none of the panic. The AI arms race between the US and China appears to have taken an unexpected turn. The US and China have been racing to develop new, more capable AI models, and to create the chips and data centres needed to train and run them. The US government has also introduced and strengthened export controls on chips to countries like China in recent years, as well as switching on and off foreign access to the latest models. Proponents think the technology can revolutionise everything from drug discovery to materials science, potentially giving economies a shot in the arm. Its increasing use in war to select targets and deploy weapons means it has become a matter of national security, too. However, the way the US and China are approaching it is very different. Chinese firms tend to release models so that users can download and run them locally, at no cost, which is in stark contrast to how most US firms host them in the cloud, provide access for a fee
Robots equipped with DeepSeek are being used for site inspections
and guard their inner workings. Open-source AIs, including those from China, don’t tend to perform quite as well as the most expensive premium models. As one UK software developer told New Scientist: “I used a local model [from Z.ai] and a cloud model
“The US could play into China’s hands if it reacts to new US models by retracting foreign access”
[from OpenAI] for the same task – it took 30 per cent longer with local, but was fully free.” Soon after Z.ai released GLM-5.2 last month, it was ranked the most intelligent open-source AI available on the market by Artificial Analysis, an AI benchmarking company. Z.ai says that it outperforms OpenAI’s GPT- 5.5 on a common benchmark used to test AI software engineering skills. However, Artificial Analysis found that GLM-5.2 performed
SONG WEIXING/VCG VIA GETTY IMAGES
slightly worse than GPT-5.5 on its intelligence tests – symptomatic of a lack of standard performance tests across the AI industry. Nevertheless, it appears GLM-5.2 is finding an audience. It currently ranks as the fifth-most commonly used LLM on OpenRouter, which captures only a tiny fraction of AI use but is one of the few public sources of such data. DeepSeek’s latest model sits at the number one spot with more than twice as much use. Seven of the top 10 are AIs built by Chinese companies. That GLM-5.2 didn’t cause the economic shock waves that DeepSeek’s previous model did perhaps shows how quickly we can adapt to the idea that China has caught up on AI, just as it has done with other technology like smartphones and electric cars. “It traditionally has been the case that Silicon Valley has been more innovative and China has been a fast follower that scales very effectively,” says Serge Belongie
at the University of Copenhagen, Denmark. The aggressive open- source aspect is a new dimension to this dynamic, he says. Mikhail Belkin at the University of California, San Diego, says that Chinese open-source models are highly capable and may even be more stable. American models can be withdrawn or modified at any time, whereas Chinese models can be run by anyone with a sufficiently powerful server, he says.
An open issue
David Shrier at Imperial College London says the company that ends up dominant in AI is likely to benefit from a £60 trillion market, but there are also political and tactical benefits for governments in taking part in the race. The US could play into China’s hands if it continues to react to new US models with market- leading performance by withdrawing foreign access. “You’re forcing people to develop their own ecosystems and own technology,” says Philip Torr at the University of Oxford. “You saw it with Huawei and Android: cut them off from Google’s ecosystem and they built their own.” Shrier is worried that China can further narrow the performance gap between its own models and those from the US by picking apart how Western models operate, just as US firm Anthropic has accused Chinese firm Alibaba of doing. What may save the large US companies in this race is the inertia and caution of business, says Belongie. Chinese open-source models might be free, run on a laptop and do a decent job, but for big firms, a Chinese model feels like a major risk. That’s where the big, established technology firms that already supply industry-standard software may be well placed. ❚
Game slashes dementia risk in men Cognitive training seems to help men’s brains clear plaque-causing protein
Carissa Wong
A COGNITIVE “speed training” game that cuts dementia risk by 25 per cent alters levels of beta- amyloid – a protein that clogs up the brain in Alzheimer’s disease – in men, but not in women. It is the first time brain training has been shown to influence the levels of a neurodegenerative marker, strengthening the evidence suggesting that mental exercises can boost brain health. “One of the main markers that’s indicative of future dementia risk got better for men who completed cognitive speed training,” says Hye Won Chai at Clemson University in South Carolina, who presented the research at the Alzheimer’s Association International Conference in London last week. The computer-based speed training involves recalling where objects have flashed up, with the task becoming harder as you get
Marine biology
‘bio-metal’ jaws to crush its prey
THE jaws of some sea worms are made of an exceptionally hard yet lightweight material dubbed a “bio-metal” that could have applications in engineering. Perinereis cultrifera is a type of ragworm with a long body adorned with bristles. Members of the species also have strong jaws that enable them to crush hard prey such as small crustaceans or other worms. Christian Hellmich at Vienna University of Technology and his team have been studying the worm’s jaws for almost a decade, leading them to propose that they are made of a novel material. The molecular
better. A prior 20-year study by some of Chai’s colleagues showed that people aged 65 and older who did the training were 25 per cent less likely to be diagnosed with Alzheimer’s disease or a related form of dementia compared with a control group.
“This strengthens the evidence suggesting that mental exercises can boost brain health”
In the latest study, Chai and her team recruited a separate group of 53 people from the US aged 65 and older, 13 of whom were male. About a third of the participants were asked to complete between 2 and 4 hours of speed training each week for 4.5 months. The remaining participants were told to either spend the same amount of time playing games
STEVE TREWHELLA/ALAMY
structure of each jaw combines proteins and ions of metals such as zinc, giving it characteristics in between those of softer biological materials and metals. Most recently, the team performed more than 3300 experiments in which small
such as solitaire, word search and a game similar to Connect 4, or complete another kind of brain training in which they had to strategically track objects and switch between tasks. To explore how speed training may reduce dementia risk, the team collected blood samples from all of the participants at the start and end of the training period. This revealed that, among men, speed training increased the ratio of two forms of beta-amyloid found in the blood, which suggests the training boosted the brain’s ability to clear beta-amyloid 42. This protein forms clumps called plaques in the brains of people with Alzheimer’s disease, disrupting brain function. The other two kinds of training had no effect. Some Alzheimer’s treatments, such as lecanemab, have been
indentations were made in different parts of the jaw. The way its hardness changed under this pressure followed a pattern typical of metals like copper and silver. However, the jaw also exhibited a kind of elasticity that metals can’t have, says Hellmich.
designed to help clear amyloid from the brain, but they only marginally slow cognitive decline in people with Alzheimer’s disease. The limited benefit seen in trials is probably down to these treatments being taken at a relatively late stage of the condition, when substantial brain damage has already occurred, says Andrea Castegnaro at University College London. Engaging in cognitive training to reduce beta-amyloid build-up before dementia develops may have a bigger effect on dementia because it would be done before much brain damage has occurred, says Castegnaro. However, the training had no effect on amyloid levels in female participants in the study. The team hopes to explore how speed training may benefit women in future studies, says Chai. ❚
Perinereis cultrifera’s hybrid jaws have peculiar properties
Next, the researchers developed a mathematical model of bio-metals, which shows how they might respond to strain in a unique way in which microscopic forces arise from the metal ions becoming arranged into lines similar to certain defects in crystals (Biophysics Reviews, doi.org/hcbbwh). “The jaws of bristle worms are incredibly hard yet very lightweight,” says Matthew Lehnert at Kent State University in Ohio. “Many industries, from automobiles to aeronautics, are searching for new ways to develop hard and lightweight materials. The answers are provided in nature!” ❚
Archaeology
princesses wielded weapons
Chris Simms
MUMMIES from about
3800 years ago reveal that
Ancient Egyptian princesses
were probably using bows and
daggers and put themselves
at risk of serious injury.
Weapons have been found
buried with women from many
cultures throughout history.
But there has been much debate
about whether this was symbolic
or meant the women used them.
Now, Zeinab Hashesh at
Beni-Suef University in Egypt
and her team have studied
six royal mummies, five female,
found at the Dahshur pyramid
and tomb complex from Egypt’s
Middle Kingdom between
about 1850 and 1700 BC.
The mummies, some of which
were found alongside bows
and arrows, were excavated
in the 1890s, and were
rediscovered in the Egyptian
Museum in Cairo in 2020.
The team has analysed
the bones to learn about the
lives of these royal individuals,
four of whom are thought
to be daughters of the
pharaoh Amenemhat II.
A key finding was that
Princess Ita – who had an
elaborate gold and lapis lazuli
dagger in her burial assemblage
and was aged between 28 and
34 when she died – would have
had strong connections between
the bones in her forearm and
strong hand muscles. This
implies the habitual gripping
of weapons like daggers
or maces, says Hashesh.
Princesses Noub-Hotep
(aged between 40 and 44)
and Itaweret (aged 20 to 34)
both showed enlargement of
the radius bone in the forearm,
which could be an adaptation
to the repetitive stress of
drawing a bow. The former
princess, who was buried
alongside arrows, also had bowing of the second right metacarpal bone in the palm and strengthened attachments of finger muscles. These hint at the sustained mechanical load required to hold a bow and are indicative of “archer’s grip” (Frontiers in Environmental Archaeology, doi.org/rf2s). “To develop the archer’s grip and the structural bowing of the hand bones observed in Noub-Hotep, they must have begun training in archery and martial arts from a young age,” says Hashesh. Michelle Langley at Griffith University in Australia says this study gives us real insight into these princesses’ lives. “Royal women were not simply sitting around a palace or following their menfolk around, but living active and skilled lives. They were trained in very practical martial and hunting arts, just as we imagine their fathers and brothers were,” she says. The bones also revealed that injuries were common. For example, Princess Itaweret
“They must have begun training in archery and martial arts from a young age”
survived broken ribs and foot fractures, which Hashesh says were probably caused by accidents or hard blows. “This tells us that they were out in the world, perhaps engaged in high-impact activities where falls and blows were a real danger,” she says. But Sonia Zakrzewski at the University of Southampton, UK, says that other activities could result in similar alterations to arm and hand bones, such as juggling or using a scythe. ❚
Zoology
BO is new to science
James Woodford
DANIEL ROSENGREN
A MONKEY with a distinctive mask-like face, found in a remote part of the Democratic Republic of the Congo, has been declared a new species. The monkey is known as likweli to local people and it has been given the scientific name Colobus congoensis. One of the most intriguing features of likweli is its facial appearance, says Kate Detwiler at Florida Atlantic University. The light-coloured skin around the mouth and beneath the nose is unlike that of any other African colobus species. Like other colobus monkeys, likweli also has a distinctive body odour that defies description, she says. Scientists first became aware of the species in 2008 when a team surveying on the banks of the Lomami river, in what is now Lomami National Park, took a photo that showed only a part of an unknown monkey, in the canopy. Then, in November 2018, another group again spotted the monkey, which is about 1.3 metres long and weighs around 7 kilograms. Between 2018 and 2022, there were 114 recorded observations of the new species, 25 of which were from vocalisations.
Colobus congoensis has a unique “mask” and orange lips
In 2021, several monkeys that had been killed by hunters were confiscated and handed over to researchers. Detailed morphological and genetic analysis confirmed they were indeed a wholly separate species (PLOS One, doi.org/hcbp8q). Genetic tests and recordings of their vocalisations also added to the evidence of their uniqueness. “The genetic analyses revealed that likweli is a deeply divergent lineage that split from its closest known relative, Colobus satanas, approximately 4 to 5 million years ago,” says Detwiler. Likweli is isolated from C. satanas by more than 1200 kilometres and several major river barriers. Unlike most other members of the genus, which have habitats exceeding 60,000 square kilometres, likweli is only known to exist in 1700 square kilometres of rainforest. Because of the risk of poaching and the monkey’s small population and home range, the team is proposing that the species should be listed as endangered. ❚
Cancer
cancer saved by cell therapy
Alice Klein
MEHAU KULYK/SCIENCE PHOTO LIBRARY
FOUR children with traditionally incurable brain cancers are still alive years after receiving an experimental immune- boosting cell therapy in a clinical trial. Three of them even display no evidence of disease. “These children are getting to grow up – it’s truly awesome,” says Gene Hwang at Children’s National Hospital in Washington DC. The experimental treatment, called tumour-associated antigen (TAA) T-cell therapy, was given to 33 children and young adults with either newly diagnosed diffuse intrinsic pontine glioma (DIPG), a highly aggressive form of brain cancer, or other brain tumours that hadn’t responded to standard treatments. The trial focused on these tumour types because “they’re universally fatal, there’s nothing else for them”, says team member Catherine Bollard, also at Children’s National Hospital. Children with DIPG typically survive for less than a year, but one of the treated children with this condition is still alive more
than two years after receiving the TAA T-cell therapy. Among the participants with other kinds of brain tumours, three responded remarkably well to the therapy. They had aggressive forms of recurrent glioblastoma, astroblastoma or medulloblastoma and had previously gone through up to 17 rounds of treatments like
“ I’m in contact with one family and they’re unbelievably grateful their child is still here”
chemotherapy and radiation that had been unsuccessful. Since receiving the TAA T-cell therapy, the three children are alive with no evidence of disease between two and five years on (Nature Medicine, doi.org/rfzx). “I’m still in contact with one of the families and they’re unbelievably grateful that their child is still with them today,” says Bollard. The trial was small and didn’t include a control group to compare the therapy with standard treatment, but Bollard
Not all brain cancers (dark red) respond to standard treatments
says “we’re very excited because, although it was only a phase-I safety study, there did seem to be a signal of efficacy”. It is still unclear why the treatment worked for some children but not others, she says. “No one is jumping up and down and saying ‘this is it’ just yet, but it is encouraging and it’s one step further along in our understanding of how to use cellular therapies to attack brain tumours,” says Tim Hassall at Queensland Children’s Hospital in Australia. The therapy involves taking a sample of a person’s blood, collecting immune cells called T-cells and essentially training them in a lab to target three protein markers, known as antigens, that are commonly found in paediatric brain tumours, says Bollard. This is done by exposing the T-cells to other cells that present these antigens, then selectively multiplying the T-cells that recognise them. The multiplied T-cells are then returned to the person intravenously, so their own immune system becomes better at fighting their cancer. In the trial, most participants tolerated the therapy well, with fatigue and headache being the most common side effects. Two people experienced tumour swelling, but this may have been because they already had large tumour volumes, says Bollard. “For the last 20 or so years, we haven’t really moved the dial in terms of improving survivability for these paediatric brain tumours, so it’s exciting to have a whole different treatment area opening up,” says Hassall. ❚
Health
remove microplastic from the body
Helen Thomson
A POSTBIOTIC may limit our absorption of microplastics, according to the first human trial of a supplement to remove them. It uses the rough surfaces of dead bacteria to attract microplastics, preventing them from entering cells. Microplastics, which are less than 5 millimetres long, are ubiquitous in the environment and have been detected throughout the human body, although it isn’t yet known if they cause any health conditions. Eva Berkes, co-founder of biopharmaceutical firm Quorum Innovations in Florida, and her team created the postbiotic, called Qi601, by growing the bacterium Limosilactobacillus fermentum, killing it with heat and collecting its cell walls. They then exposed human intestinal-like cells to nanoplastics – less than 0.001 mm – with and without the postbiotic. When Qi601 wasn’t present, nanoplastics accumulated within cells and on their surfaces. But when Qi601 was added, significantly fewer nanoplastics were visible inside or on the cells, suggesting that the postbiotic mopped them up before they could be absorbed. The team also asked participants to chew commercial gum, which releases numerous microplastic particles into saliva, until they had collected 10 millilitres of saliva. The researchers then repeated the experiment, but placed 10 milligrams of powdered Qi601 in the participants’ mouths after 5 seconds of chewing. Analysis of the saliva from one participant showed 2152 freely floating plastic particles after chewing gum alone, compared with 185 when Qi601 was added (bioRxiv, doi.org/rf3k). “Our results represent the first demonstration of microplastics being bound by a microplastic mitigant in [people],” says Berkes. ❚
Maya astronomer’s name decoded Hieroglyphs on the wall of a Maya building record calculations concerning planetary orbits
James Woodford
AN ANCIENT Maya astronomer- mathematician has been identified for the first time along with his complex calculations made around 1200 years ago, predicting the orbital cycles of Mars and Venus. “This is the first direct mention of an ancestral Maya astronomer-mathematician by personal name,” says Franco Rossi at the Massachusetts Institute of Technology. The Maya civilisation flourished in Central America between about 2000 BC and AD 1697. They had advanced knowledge of astronomy and mathematics, but much was lost after the mass burning of their books by Spanish missionaries. Since 2010, excavations at the site of Xultun, Guatemala, have revealed astronomical and mathematical inscriptions inside a small masonry building. On the east and north-east walls of the building are around 50 texts that scientists believe are “rough drafts” made by Maya mathematicians as they charted and predicted the
Animal behaviour
smell controls naked mole rat colonies
THERE’S one scent to rule them all – and we now know what it is. A series of experiments has shown that a single molecule released by the queen of naked mole rat colonies prevents all the other females in a colony from breeding. “It’s a super-contraceptive, if you’re a mole rat,” says Gary Lewin at the Max Delbrück Center in Berlin. Naked mole rats (Heterocephalus glaber) have a social structure like that of bees and ants, with colonies made up of soldiers and workers, and a single queen ruling each
PROYECTO REGIONAL ARQUEOLÓGICO SAN BARTOLO-XULTUN; PRASBX
The inscribed texts were found within this chamber in Xultun, Guatemala
cycles of celestial objects relative to Earth and to one another. Rossi and his colleagues have painstakingly deciphered one of these murals, named Text 19. At the bottom of the mural is the name of Sak Tahn Waax, which translates to White- chested Fox, who is believed
colony. Only the queen can breed, but how she maintains her long reign – Lewin’s team’s oldest queen is 39 – hasn’t been clear. “The theory was that the queen is larger and more aggressive than the other animals, exerting her dominance through pushing and shoving,” says Lewin. “But we never found that very satisfying as an explanation.” So, team member Mohammed Khallaf, also at the Max Delbrück Center, proposed identifying the mole rat bouquet – the molecules in the air around them that create their scent. Comparing the scents of hundreds of animals revealed that only the queens produce a molecule called isopropyl myristate.
to be the author of the formula. Text 19 consists of 11 hieroglyphs, which had to be scanned, photographed and magnified under different light angles, and compared with later, astronomical- mathematical writings, before their meaning could be deduced (Antiquity, doi.org/rfzp). While similar mathematical and astronomical expertise is found across Maya cities, the mention of Sak Tahn Waax, who the researchers believe was probably male, is unique. “Whether this is an instance of the scribe himself signing his own calculation or attributing the intellectual work to another, we have a formula and the name of its creator, which serves to demonstrate the importance of this kind of intellectual contribution for Classic Maya people,” says Rossi. The calendar system on display in Text 19 uses maths in relation to time periods, he says. These time periods were drawn from
NEIL BROMHALL/SHUTTERSTOCK
“It’s made in the reproductive organs, basically the vagina of the reproductive female,” says Lewin. When the team sprayed isopropyl myristate daily into cages containing male and
a 260-day calendar, a 365-day solar calendar, a 584-day approximation of Venus’s synodic cycle (when the planet returns to the same position relative to both Earth and the sun) and a 780-day approximation of Mars’s synodic cycle. The total length of the formula is five Venus synodic cycles or 2920 days, and the
“ We think it is meant to show the relationship between these two planets and human counts of time”
date that Text 19 most likely refers to is 7 November of AD 781 in the Julian calendar. Exactly how this formula would have been applied is unknown. “We think it is meant to concisely and meaningfully show the relationship between these two planets and human counts of time in ways that could then be applied to political ceremony, predictive astronomy and understandings of seasonality,” says Rossi. ❚
The queen is the only female naked mole rat allowed to breed
female pairs, none of the females became pregnant. Without it, almost all the females became pregnant (Nature, doi.org/rfzq). Next, the team removed a queen from a colony and applied isopropyl myristate daily. There were no fights for succession and no females started breeding during the three months this was done. When the team stopped applying the chemical, the high-ranking females started fighting within a week. After around three weeks, one became pregnant: the new queen. ❚
Jacob Aron is a senior editor at New Scientist, writing about maths, physics and technology
Jacob’s week
What I’m reading The Ministry for the Future by Kim Stanley Robinson, a bit of a struggle in the recent heat
What I’m playing Selaco, a fantastic first-person shooter in the grand tradition of Doom and Half-Life
What I’m working on A feature about the far future, hence the reading material!
Sneaky maths A trick to solving problems without answering them brought mathematicians to blows 100 years ago, but it’s now a common part of maths, discovers Jacob Aron
A MATHEMATICIAN opens her office door to find a small fire. Without panicking, she looks around the room and spots a fire extinguisher. “Ah, a solution exists!” she says, before closing the door and continuing on with her day. Simply knowing it is possible to extinguish the fire is proof enough that the problem can be solved – why bother to actually do it? This old joke sums up how a lot of modern mathematics gets
“ Hilbert thought it was
ridiculous, comparing
the restrictions to
‘prohibiting the boxer
the use of his fists’ ”
done, thanks to a sneaky tactic for problem-solving: the non- constructive proof. It is a tricky idea to get your head around, so here’s a mostly non-mathematical example. Say there are 367 people in a room – what are the chances that two of them share a birthday? The answer is 100 per cent, because (assuming we account for leap years) there are only 366 possible birthdays, and each person must have a birthday, so at least two people must have the same birthday. This is an example of what mathematicians call the “pigeonhole principle” – the people are the pigeons, the holes are the birthdays – and it’s a classic way of approaching non- constructive proofs. We know that two people must share a birthday, even if we have no idea who, out of the 367 people, they are. Traditionally, proofs were the exact opposite of this. If you proved something, generally you had grasped a concrete mathematical object and laid it out on display for everyone to see. That all began to change in the 19th century, when non-constructive proofs became a
more powerful and popular tool in a mathematician’s arsenal. At the forefront of this new way of doing mathematics was David Hilbert, one of the great mathematicians of his time and, at least in the eyes of some, a troublemaker. The problem Hilbert was investigating is a complex one and requires a little table-setting. Let’s start by thinking about a square. You can rotate a square by 90 degrees and it ends up looking the same – you may be familiar with this as being called rotational symmetry. Another way to describe it is that the square is “invariant” under 90-degree rotations. Hilbert was interested in invariants, not for geometrical objects like squares, but algebraic ones like equations. For a given class of algebraic object, mathematicians had realised that there are essentially an infinite number of invariants. The question then became: how many do you actually need? Can you start with a few key invariants and use them to build any other invariant you like? Hilbert wasn’t the first person to tackle identifying a “generating set” for invariants – another
A mathematical proof provides a logical argument that a theory is correct
LUCIDIO STUDIO, INC./GETTY IMAGES
mathematician, Paul Gordan, had spent his entire career investigating it. Gordan had discovered finite generating sets for a few objects, but his proof was messy and complex. He was astonished, then, when in 1888 Hilbert came along and proved that it was true for a much larger class of algebraic objects – without actually specifying the make-up of the generating sets. He did this by first assuming that there is an invariant that cannot be produced by a generating set, then showed that this would lead to the creation of an infinite stream of more invariants in a manner that isn’t allowed by the algebraic rules Hilbert was operating in – a logical contradiction. The only way to resolve the contradiction, then, is that the generating set must always exist.
Maths divisions
Gordan’s reaction to this non- constructive proof was initially negative. “That is not mathematics, that is theology,” he said, aghast that Hilbert would ask him to believe in the existence of a generating set without providing one – surely that doesn’t count as an answer? Gordan came around to Hilbert’s way of thinking, though, later stating
that “theology does have its advantages”. Hilbert’s battles weren’t over yet. Just as he was a young upstart challenging Gordan, so, too, came a younger upstart in the form of L.E.J. Brouwer. Hilbert spent a good few decades building up the mathematical philosophy of formalism, which essentially takes the view that mathematics is a game of manipulating symbols in a logical way to produce proofs, without being too concerned about the real-world or mathematical objects those symbols might correspond to. For formalists, a non-constructive proof is simply one of many ways to win the game. Brouwer hated this idea. His philosophy was intuitionism, which argues that mathematics is a creation of the human mind. He rejected the manipulation of symbols as the underlying activity of mathematics, seeing them only as a way for relaying thought from one mathematician to another. In this view, a non-constructive proof is cheating – for a mathematical object to be real, you must be able to construct it in your mind. Where these two philosophies really clash is over something called the law of the excluded middle. This is an ancient principle of logic that states that, for every logical proposition, either that proposition is true or its negation is. In other words, if I say, “Hilbert was a cat”, either that must be true or Hilbert wasn’t a cat (it’s the latter, for the avoidance of doubt). This may seem obvious, but it turns out to be a useful mathematical tool. In Hilbert’s 1888 proof, he assumed that “not all invariants can be produced by a finite generating set” and found a contradiction, making that proposition false. By the law of the excluded middle, “all invariants can be produced by
ULLSTEIN BILD VIA GETTY IMAGES
a finite generating set” must be true, even without showing how to construct such a set. Brouwer’s objection was in applying the law of the excluded middle to an infinite set of objects, as Hilbert was doing. He had no issue in using it for finite sets, because, in principle, you could check every object in the set and convince yourself that they have or don’t have a certain property. But for infinite sets, this can’t be done. Hilbert thought this was ridiculous, comparing restrictions on the law of the excluded middle to “prohibiting the boxer the use of his fists”. Brouwer, in turn, referred to Hilbert as “my enemy”. This was a problem, because both men worked on Mathematische Annalen, then and today one of the most important journals in mathematics. Hilbert was one of three editors, alongside Albert Einstein, while Brouwer was on the editorial board. Hilbert was so
David Hilbert was key in building up the mathematical philosophy of formalism
“ Formalists see mathematics as a game of manipulating symbols in a logical way to produce proofs”
incensed at Brouwer’s influence over the journal that, in 1928, he fired the entire editorial board just to get rid of him. In response, Einstein resigned from his post as well, asking, “What is this frog and mouse battle among the mathematicians?” In practical terms, Einstein was right to dismiss the argument. Today, very few mathematicians concern themselves with an explicit philosophy, and the vast majority are happy to employ non-constructive proofs as a useful tool. You could say this meant Hilbert won, and certainly Brouwer became an increasingly isolated and irrelevant figure after his dismissal from Mathematische Annalen. But as I’ve written previously, Hilbert’s formalism would soon be dealt a fatal blow by Kurt Gödel, whose incompleteness theorem showed that the game of manipulating symbols could never be fully consistent. Gödel wasn’t an intuitionist – in fact, his completeness theorem, a precursor to the incompleteness one, relies on the law of the excluded middle – but he did take inspiration from Brouwer in his own fight against Hilbert. Gödel and Brouwer’s ideas would later become important in computer science, informing the work of Alan Turing and questions about which problems are computable. Today, such ideas are coming back into fashion as mathematicians turn to AI and formal proof verification, in which every step of a proof must be made machine-readable to verify it as true. That, in turn, may one day lead to a non-constructive proof, verified as logically true, that mathematicians nevertheless don’t fully understand because it was created by an AI that can’t explain it to human minds. If that comes to pass, Brouwer will get the last laugh. ❚
Chanda Prescod-Weinstein is an associate professor of physics and astronomy at the University of New Hampshire. She is the author of The Disordered Cosmos. Her latest book is The Edge of Space-Time: Particles, poetry, and the cosmic dream boogie
Chanda’s week
What I’m reading Both Lonely Crowds by Stephanie Wambugu and The Adjunct by Maria Adelmann tackle campus life in interesting ways
What I’m watching I really loved Is God Is and enjoyed Supergirl
What I’m working on I’ve been selecting a textbook for a quantum field theory course
stuck together by weird glue-like particles – but they aren’t real, explains Chanda Prescod-Weinstein
THIS October, I’ll be speaking at New Scientist Live in London about the wonders of dark matter, the invisible matter that dominates galaxies. When I give talks like this, I emphasise the difference between dark matter and visible matter, the stuff we are made of. To highlight the point, I stress that humans are a collection of quarks and electrons – as are most things in the universe. This is maybe a funny way of describing humans, which we tend to think of as biological in nature. If you ask a physiologist what a human is made of, they’d probably say something like, “We are 60 per cent water and about 20 per cent carbon, plus a smattering of other things.” In other words, we are mostly hydrogen and oxygen. That’s technically correct, but a physiologist sees it somewhat differently from a physicist, who drills down beyond the atomic level. Consider hydrogen, the simplest atom. In its most basic form, hydrogen is composed of a proton in its atomic nucleus, with an electron in orbit. Hydrogen can also have one or more neutrons. Meanwhile, oxygen has eight protons in its nucleus, up to eight electrons and as many as 20 neutrons. Every atomic element is some combination of these subatomic particles, so you
“ We call them ‘virtual’ particles because they are so incredibly short- lived that it’s like they don’t exist at all”
might think a particle physicist would answer, “Humans are made of protons, neutrons and electrons.” But one of these things is not like the others: electrons are fundamental, indivisible particles. Protons and neutrons are composites. A proton is made of two up quarks and one down quark, while a neutron is the reverse, two
PHOTOJUNCTION/ALAMY
Quarks are never alone, and a special particle called a gluon makes sure they don’t drift apart
down quarks and one up quark. A quark, like an electron, can’t be broken down into anything smaller. So, returning to the question of what humans are made of, I have frequently told people that we are collections of quarks and electrons. As I’ve toured for my new book, The Edge of Space-Time, I’ve started to think more and more about whether this is a fair rendering of the situation. There’s another particle that I should be including – well, maybe. The complication comes in part from how quarks are bound together. Quarks, uniquely, never exist on their own. They are always in combinations with other quarks. Their most stable combinations are the three-quark combinations we know as protons and neutrons. There are many other three-quark composite particles, as well as two-quark and pentaquark (five-quark) combinations, but all of them are unstable and short-lived. But what you’ll never see is a lone quark and that’s because of the way the strong force works. The strong nuclear force, which holds quarks in place, is so powerful that if we try to pull a quark out of, say, a proton, the energy involved would be enough to create another quark and an anti-quark, which is
effectively an antimatter version of a quark. Same mass, opposite electric charge. In the end, the quark is still bound to something, never escaping at all. That’s because of another particle: gluons. Yes, we have particles that glue quarks together called “gluons”! So you might think that I should really be telling people that humans are electrons, quarks and gluons. The strong force happens because quarks interact via gluons, so including them in the ingredient list would seem to make sense. But there’s a catch: gluons are a little different from quarks and electrons because they aren’t real. That’s not a typo. Gluons play a meaningful physical role in holding matter together, but they are also complete weirdos: they have no meaningful physical existence. In fact, we call them “virtual” particles because they are so incredibly short-lived that it’s like they don’t exist at all. Virtual photons also pop up in atoms, as part of electromagnetic interactions, and I’m not at all ready to claim people are made of particles of light. So, when I explain that we are collections of electrons and quarks, I leave out gluons. The strangeness of gluons also highlights one of the ways in which “particle” isn’t really a good way to talk about what happens inside of an atom. The idea of a particle conjures the image of a tiny billiard ball. But this visual metaphor doesn’t serve us particularly well when trying to imagine something that’s barely there. For this reason, I’ll probably stick to saying we are phenomenal collections of quarks and electrons, but I guess we’ll see in real time in October whether I’ve changed my mind about the importance of including the elusive yet powerful gluon. ❚
To find out more about New Scientist Live, head to newscientist.com/nslmag
Sculptor Jason deCaires Taylor
CLIMATE and health activist Gladys Bartlett has been immortalised in a sculpture, The Solomon Siren – recently installed on her now-flooded former home: Kale Island in the Solomon Islands. Rising tides completely flooded the 50,000-square-metre Pacific island in 2016. The sculpture sits in the intertidal zone, where patches of rubble and sand rise above the ocean surface from time to time. Sculptor Jason deCaires Taylor made the sculpture as part of his Sirens series of installations around the world highlighting warming seas, sewage pollution and the presence of microplastics. When flooding made life untenable, Bartlett and her family had to evacuate to one of the main islands. “Back then, [the island] was land – green, vibrant, full of life,” says Bartlett in a film accompanying the sculpture’s installation. “Kale became one of the first documented islands in the Solomons lost to sea level rise.” The sculpture consists of a marine-grade stainless steel tree on which a life-sized figure of Bartlett leans. The artwork also uses biochar and pH-neutral cement. Hauntingly, as the tide rises and falls, it is intermittently hidden as waves roll over. Incorporated into the sculpture are inscriptions recording past milestones of Kale’s submergence along with predictions for a sea level rise of up to 20 centimetres by 2046. But as Taylor says, the sculpture isn’t intended to work as a scientific measuring instrument, but as a “symbolic representation” of a changing relationship between land and sea. “What happened is a warning not only for us, but for the world,” says Bartlett. ❚
While recent heatwaves made us stick to the shade, an intriguing book reveals sunlight’s health-giving effects – in moderation, finds David Robson
Book
In Defense of Sunlight
Rowan Jacobsen
Scribner
ABOUT a hundred years ago, doctors actively encouraged sunbathing. Soldiers’ wounds, first world war surgeons had noticed, healed a lot faster when exposed to solar rays; people with arthritis felt their pain retreating, while those with bronchitis and lung infections found their coughs subsiding. Blood pressure in hypertensive patients dropped. The Lancet went so far as to declare it “one of nature’s greatest aids to maintaining and acquiring proper health”, and even called for more spaces to strip off in public. “On first consideration, the idea of a community of people deliberately practising nudity, especially with municipal encouragement, strikes the average person as somewhat ridiculous,” reads one article from 1932. “But the discovery that the rays of the sun on the skin exert a beneficent effect on health has done
Three more great books on the sun’s role in our lives
Life Time: The new science of the body clock, and how it can revolutionize your sleep and health by Russell Foster
Many of us extend our days far into the night. Russell Foster’s guide to human circadian rhythms shows why this is a poor idea. Using his research, he urges us to harness them to enhance sleep, mood and mental focus.
something to undermine these prejudices… as long as they are done for the sake of health and… the sexes are segregated.” Today, we’re far more cautious. We are told to cover up and apply generous volumes of sunscreen to protect us from the harmful UV rays, even in the winter. But has this advice gone too far? That’s the argument of a fascinating new book, In Defense of Sunlight: The surprising science of sun exposure by journalist Rowan Jacobsen. He says he was inspired by the finding that
“ Studies found that exposure to UV light releases nitric oxide in our skin, which reduces blood pressure”
sun exposure can trigger mood- boosting endorphins. “Like most people, I’d had it drilled into me since childhood that the sun was... the primary cause of skin cancer, and that the only acceptable amount of its rays that should be allowed to touch my unprotected skin was zero,” he writes. “But if
The Remarkable
Life of the Skin: An
intimate journey
across our surface
by Monty Lyman
The skin is our largest, fastest growing and least understood organ. It is also, of course, the principal recipient of the sun’s rays. Doctor and research fellow Monty Lyman explores the organ’s major role in our health.
we’re wired to seek out sunlight, there must be a reason.” Despite this slightly shaky premise (the brain’s pleasure system can prime us to seek out much that is unhealthy for us, including drugs, alcohol and sugar) Jacobsen builds a thoroughly convincing argument, as he documents the many surprising ways that moderate sun exposure can revitalise our bodies. The most famous benefits of sunlight once appeared to revolve around its role in the body’s production of vitamin D. Correlational studies suggested that high levels of the chemical seem to reduce the risk of many health problems, including obesity, diabetes, osteoporosis, heart attack, stroke, depression, respiratory infections and colorectal cancer. Yet Jacobsen notes that dietary supplements of the vitamin have largely failed to make an impact on any of these problems, except when someone has a severe deficiency. This leaves the intriguing possibility that measurements of people’s natural vitamin D levels were simply acting as a proxy of their
Chasing the Sun: The new science of sunlight and how it shapes our bodies and minds by Linda Geddes
Former New Scientist staffer Linda Geddes offers an in-depth exploration of the sun’s role in our lives across history and cultures – and exactly what we lose when we end up spending so much of our time indoors.
overall sun exposure, which had been protecting the body through multiple other mechanisms. One likely pathway is nitric oxide, a chemical that causes our blood vessels to dilate. Scientists have recently started to conclude that nitric oxide deficiency is a major driver of hypertension, and – quite remarkably – a series of studies has found that exposure to UV light releases this tiny chemical in our skin, which then reduces blood pressure. The finding, Jacobsen suggests, may offer one more reason why people in Mediterranean countries tend to have such good health. The leafy veg of the region’s famous diet, he points out, contain lots of nitrates, but plentiful sunlight in those areas helps people’s bodies to convert this into nitric oxide, relaxing their cardiovascular system. Just adopting a Mediterranean diet
has been shown to lower blood pressure, but not as much as also increasing sun exposure, writes Jacobsen: “It’s the combination of the two that does the trick and should be the foundation of a true Mediterranean diet.” Elsewhere, he points to evidence that moderate exposure to sunlight releases chemicals in the skin that help rein in an overactive immune system, which may explain why it appears to soothe conditions like multiple sclerosis – independently of vitamin D production – and type 1 diabetes. There is even evidence that the infrared wavelengths in sunlight, which can penetrate deep into our bodies, can stimulate our mitochondria, improving our metabolism. The dark cloud hanging over all this is, of course, the heightened risk of skin cancer that comes with sun exposure. Here, Jacobsen points out that most skin cancers
are basal cell and squamous cell carcinomas, which don’t often spread to other parts of the body and are typically treatable with surgery. Melanoma is more dangerous, but it is relatively rare and still has a very high survival rate compared with other cancers. “Yes, sunlight is the major alterable risk factor for skin cancer, but deaths from heart disease are
Shaded beach huts help us avoid getting too much of a good thing: sunlight
a hundred times higher than deaths from skin cancer,” Jacobsen writes. “And I think we need to find the risk-benefit ratio.” To support this, he points to an influential study of 30,000 Swedish women, which found that sun exposure was associated with a far lower risk of mortality: over a 20-year period, “sun avoiders” were about twice as likely to die as sun lovers. Clearly, we shouldn’t take this new-found appreciation of “heliotherapy” to extremes; The Lancet is unlikely to resurrect its campaign for nude sunbathing anytime soon. The balance of risks will depend on a huge number of factors, including skin tone, the season and the latitude, which makes it very hard to make general recommendations for optimum levels of sun exposure. In the end, Jacobsen’s advice is quite close to that of health services in the UK. Make the most of the mornings and evenings when the UV component is lower, he suggests, but cover up and find shade during the hottest times of day. He is a little ambivalent on the daily use of sunscreen outside of the riskiest periods, but agrees it is advisable whenever there is the possibility of burning. Even short periods of exposure, he says, may be enough to glean the benefits. For all the cutting-edge research this thought-provoking book describes, its message is remarkably simple. “Get sun. Not too much. Go outside.” It’s time we all saw the light. ❚
JUSTIN TALLIS/AFP VIA GETTY IMAGES
David Robson is a science writer specialising in the human brain, body and behaviour. His latest book is The Laws of Connection: 13 social strategies that will transform your life
recommends
Rowan Hooper Podcast editor London
Anish Kapoor‘s major retrospective at London’s Hayward Gallery is amazing, awe-inspiring and terrifying by turns. On until 18 October, it invokes religious themes, but also raises questions about reality and space-
time. Take Mount Moriah at the Gate of the Ghetto, named after the biblical mountain where God told Abraham to sacrifice his son. Kapoor suspends the gigantic mountain from the ceiling, soaking it in shiny red pigment that looks like blood and exposed flesh – or lava? Another room houses Kapoor’s Ha Makom (above), a vast, rocky, crimson landscape with a black rectangular portal in the centre. According to Kapoor, it draws on the presence of the divine, and is influenced by visits to Uluru in Australia. It is one of a few pieces using Vantablack, a wonder pigment made of carbon nanotubes that absorbs 99.96 per cent of light. Kapoor uses it to create voids and what appear to be rifts in space-time, a taste of what a physicist might experience grappling with the fabric of reality.
DAVE MORGAN. COURTESY OF THE HAYWARD GALLERY AND THE ARTIST. © ANISH KAPOOR
Extra value Two great reads this week: Sublimation, a taut thriller set in a world where crossing an international border splits you into two identical copies, and Moss’d in Space, a super cosy yet funny sci-fi novel. Emily H. Wilson enjoyed both
Emily H. Wilson is the author
of the Sumerians series
(Inanna, Gilgamesh and
Ninshubar, all published by
Titan) and she is currently
working on her first sci-fi
novel. She is a former editor
of New Scientist and you
can follow her on Instagram
@emilyhwilson1
Book Sublimation Isabel J. Kim Picador
Moss’d in Space Rebecca Thorne Tor
Emily recommends...
Book Time to Burn Ellery Lloyd Macmillan Another new release this month, featuring journeys back in time to the London Blitz. This twisty time-travel thriller, which you can easily imagine going straight to film, is enjoyable and clever; in short, a romp
FLORENT DRILLON/MILLENNIUM IMAGES, UK
IN SUBLIMATION, Isabel J. Kim imagines a world where someone attempting to cross an international border may end up splitting into two separate beings. So, for example, if you were leaving your home country for pastures new but were torn about whether you were making the right decision, you might find yourself splitting into two at the airport. One “instance” of you would leave, and another would stay behind. The instances are identical at the moment of cleaving, but after that, their memories and lives are their own… unless they happen to touch, flesh to flesh, in which case they may reintegrate, their two selves smashing together again. It is undoubtedly a complicated premise, but don’t be put off. The execution is light and graceful, and the intricacies of the set-up prove both moving and thought- provoking. Kim makes the cleaving of a human in two feel very natural – the way the world has always been. She also uses an unusual second-person point of view. Two sample sentences: “You
shake your head.” And: “You scratch the black cuff on your wrist.” In less-sure hands, this might be confusing. Here, it is intimate and interesting. Our heroine is Soyoung, a young woman in Seoul. We first meet her as she mulls over whether reintegrating with your instance against their will amounts to murder: a gun on the wall if there ever was one.
“ Sublimation’s premise is complicated, but don’t be put off. The execution is light and graceful”
Soyoung has an instance she has never spoken to living in New York; that version of herself now calls herself Rose. Meanwhile, Soyoung’s best friend is a man named Yujin, and he also happens to have an instance living in New York. Yujin is very close to his instance, named YJ, and the pair are working together towards shared goals. They intend to reintegrate when they hit 30. Or at least, that was the original plan, but it has been
What happens if the two versions of yourself meet up – and touch?
a long time since they were one, so perhaps all is not what it seems. When Rose returns to South Korea after the death of the grandfather she shares with Soyoung, she and Soyoung meet for the first time. It is an awkward meeting, because the two women don’t trust each other, and with good reason. Their reunion triggers dramatic events that will soon draw Yujin and his instance, YJ, into a high-stakes chain of events. This is a taut psychological thriller, full of unexpected twists. It is fantastically well written and well constructed. I could have done without the more routine action thriller aspects, involving big tech and baddies being exposed. I’m not sure the book needed it with so much going on between our pairs of instances. But that’s a smallish gripe. This is tip-top stuff; a fantastic debut. And a second recommendation this week, for those who like their sci-fi very cosy. Moss’d in Space by Rebecca Thorne is about an alien starship covered with intelligent… moss. Yes, Moss’d in Space is about moss. Or specifically, a moss organism called Moss. I thought the title was dreadful until I got into the book, at which point I decided it was genius. Cosy fiction is absolutely not my thing, and this is marshmallow sweet, but I finished it because quality tells and this is quality. Thorne has the gift of being very funny, with the book’s humour elegantly wrought from the gulf between Moss’s idea of itself – as a delightful and easy-to-get-on-with person – and the reality of Moss’s sneaky, intransigent, easy-to-upset character. This is the first in a series, and it deserves to do well. ❚
Editor’s pick
Complexity shapes our view of the universe
18 July, p 40
From Carl Zetie,
Raleigh, North Carolina
Stephen Wolfram’s suggestion
that the universe is essentially a
computer calculating a succession
of states reminded me that, for
as far back as we can tell, humans
have described the physical world
by comparing it to the most complex
thing they know at the time.
In prehistory, this was
ourselves, so we explained the
universe in terms of malicious
gods and capricious spirits
who were pretty much like us.
The scientific revolution of Isaac
Newton, Nicolaus Copernicus and
Galileo Galilei spawned physical
laws based in differential calculus,
equations with (theoretically) precise
solutions, and so the universe was
described as the most complex
piece of clockwork imaginable.
In the 19th century, with the
rise of statistical theory and the
industrial revolution, we thought
of it in terms of thermodynamics –
like an incredibly complex steam
engine. And in the 20th century,
the digital computer arrived –
no surprise, then, that we came
to understand the universe in
terms of information theory and
computability. I predict it is only a
matter of time and wider familiarity
before the universe is compared
to a quantum computer.
Whenever we are presented
with a model of what the universe is
really like, we should pause and ask
ourselves whether we are looking
at a new idea or an old mistake.
Thoughts on the world’s speediest spider
4 July, p 16 From Talia Morris, Cape Tribulation, Queensland, Australia You report that a species of huntsman spider found in Queensland, Australia, has been crowned the world’s fastest. As
a resident of Cape Tribulation in Queensland and a longtime friend of our local huntsman spiders, I can offer an additional explanation for their speediness: temperament. Huntsman spiders are shy and nervous by nature. Fleeing is their main survival strategy. A huntsman will bolt at a sudden noise, a puff of air blown on them or a shift in lighting. Now you see them, now you don’t.
From John Newton,
Rous Lench, Worcestershire, UK
On the wooden floor of my
kitchen in the UK, I observe small
spiders moving very fast indeed.
They are less than 2 millimetres
across, too small for me to identify.
Surely speed should be judged
in relation to body size?
Stimulating work in my 70s improved my memory
20 June, p 38 From George Wallace, Farnborough, Hampshire, UK I read your article about superagers, those who retain an unusually keen memory into their 80s and 90s. I am 71 years old. Before I retired, aged 70, from working on complex systems, my brain seemed to be slowing down. My job, though it sounds grand, wasn’t that demanding. I found that I would forget things and people’s names. My retirement lasted only four days. I was soon contacted by a tutoring company to teach maths. I started picking up students, but found I had to take my GCSE maths again since it had changed so much. Once I had done so, I started on my A level maths. This kept me busy alongside my students. After about a year, I started to notice a profound change: my memory started
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to become very sharp and I could remember things that were a blur before. I have also kept myself fit by race-walking 40 miles a week.
Adapting to climate change means embracing nuclear
Leader, 4 July From Mark Pickin, Easingwold, North Yorkshire, UK In “Rising heat”, you say we must act quickly to adapt to climate change. It is clear to me that the only way out of this mess is for us to invest in an environmentally sensible carbon-free energy source that can produce what we need on demand and at a cost to the consumer that makes fossil fuels economically unviable. The only technology that really makes sense is fusion, but that remains too far off. We need to embrace that, in the short to medium term, small modular fission reactors are the only off- the-shelf solution that can help fill the gap, and that fossil fuels will remain a significant energy source for at least the next 20 years. That leaves us no choice but to buy time and find some way of at least slowing climate change down. It is indisputable that volcanic eruptions can substantially cool Earth, and it would therefore seem logical to use geoengineering to emulate this effect.
We underestimate SpudCell at our peril
11 July, p 8
From Peter Bickerton,
South Wootton, Norfolk, UK
Michael Le Page informs us of
SpudCell, a prototype synthetic
cell partly capable of replicating
itself. The article asks whether
it could be dangerous and
boldly answers “no”.
But surely we aren’t so arrogant as to assume that we can prevent evolution? Microorganisms swap bits of genetic information all the time, and can avert our best efforts to repress them. Synthetic biologists are overconfidently toying with something we aren’t even close to fully understanding, and have crossed way beyond the line of hubris.
A grisly end for an
Iron Age tribal leader?
20 June, p 13
From John Woodgate,
Rayleigh, Essex, UK
You write that archaeologists
have found evidence that a
woman interred in Iron Age
Britain may have had her
brain removed after death.
I can imagine a scenario where
the woman was a prominent tribal
leader and the teenage boy buried
with her was her heir. Perhaps
they were killed by a rival tribe
in an ambush and the woman’s
bones were desecrated. Later,
her remains and those of the
boy were recovered and she
was re-buried with honour.
Pure speculation, of course;
the film and TV rights are for sale.
After 50 years of reading, there is still more to learn
20 June, p 30 and p 34
From Dave Holtum,
Bath, UK
I have been reading New Scientist
on and off for more than 50 years,
and always enjoy the new
perspective it brings. It isn’t
often, though, that two articles
about things I have never heard
of are presented in the same
issue. I am referring to
coacervates, the mysterious
droplets found in our cells,
and the strange state of matter
known as many-body localisation.
It reminded me how little
I know and that I, and science
in general, still have a fair
way to go yet. ❚
STEPHAN SCHMITZ
O
RDER and chaos. Nature and nurture. Yin and yang. We are fond of carving the world into two. Physics, at first, seems to oblige. Take the universe’s unruly zoo of fundamental particles and it seems to fall into two camps. Boil it all down and you have matter and forces. Together, they make up a pleasingly simple recipe for reality. Except physics has a way of spoiling simple recipes. In recent mathematical work, researchers have discovered a potential third category of particles. These so-called paraparticles would be neither matter nor force, but something stranger in between. And unlike either bosons or fermions, they would obey an alternate set of quantum rules, first proposed decades ago, then largely dismissed. Thanks to new mathematical insights, paraparticles may be more viable than anyone thought. No one has seen one in nature, but the stakes are high. If paraparticles exist, it would shake our understanding of reality. The standard model of particle physics, our best current theory of the fundamental ingredients of the universe, already has gaps: it omits gravity and can’t explain dark matter or dark energy. But paraparticles might offer a new way into those missing parts. “This would be huge,” says Vlatko Vedral at the University of Oxford. “It could mean the standard model is badly wrong.” To understand why paraparticles seemed impossible, it helps to return to the two kinds of particle we know exist. There are fermions, such as electrons and quarks, which make up matter. And there are bosons, such as photons
missing piece
are raising hopes that it could explain reality at
its deepest level, discovers Miriam Frankel
and gluons, which carry forces. Together, they compose all the fundamental particles in the standard model. Matter and messenger: the division between the two isn’t merely superficial; it seems to be written into the very mathematical structure of quantum mechanics. Quantum mechanics treats particles in a strange but strict way. Two electrons aren’t just very alike. As far as the theory is concerned, they are interchangeable. Swap them in the maths and no experiment should be able to tell that anything has happened. The maths in question is the wave function: a mathematical object that encodes the probabilities of finding them in particular states, defined by properties such as location, energy and spin – a kind of internal angular momentum. Wave functions contain odd- looking components, including negative signs and imaginary numbers. But experiments only ever yield ordinary probabilities. To get these, physicists square the wave function, making some of the mathematical oddness disappear from view. All this means that, when two identical particles are swapped, there are two possible outcomes: the wave function can stay as it is or it can flip sign. After squaring, both options give the same positive probabilities. But physically, they describe very different kinds of particles. In one case, identical particles can crowd together. These are bosons, a family that includes photons, which mediate the electromagnetic force, and gluons, which carry the strong nuclear force that binds quarks into protons and neutrons. Because bosons can have
the same quantum properties at the same time, they tend to be quite gregarious. Photons, for instance, can pile together in the beam of a laser. In the other case, identical particles are barred from sharing a quantum state. These are fermions, including electrons, quarks and ghostly particles known as neutrinos. They are mathematically forbidden from overlapping, making electrons antisocial and explaining why they occupy different shells around atomic nuclei. It is also what gives ordinary matter its stubborn solidity: squeeze atoms too tightly and their electrons have nowhere new to go, producing a quantum pressure that resists further compression.
The magic number
For decades, that seemed to exhaust all the possibilities. There was no obvious third option. But in 1953, physicist Herbert Green found one. He suggested that the wave function might have more structure inside it than physicists had assumed. When two identical particles were swapped, the wave function needn’t simply stay the same or flip sign. It could also rearrange hidden internal states that don’t show up directly in ordinary measurements. Think of two identical-looking boxes. From the outside, swapping them changes nothing: the same boxes are still there, and any ordinary inspection gives the same result. But what if there are unseen compartments inside? If so, the external sameness is preserved, even though something concealed within has changed. These are often referred to as “hidden states”, and the particles that possessed them were named “paraparticles”. These hidden states became a source of scepticism around paraparticles. No one knew what they corresponded to physically. They might be nothing more than a mathematical trick. Or they might turn out to be similar to spin – a quantum mechanical property with no straightforward classical equivalent – except hidden from ordinary measurement. “The physical meaning attached to them is going to be dependent on what they actually are in a real physical system,” says Kaden Hazzard at Rice University in Texas. Because of this, Green faced an uphill struggle. “Already at the beginning, people started asking: ‘If these exist, why don’t we observe them?’ ” says Francesco Toppan, a theoretical physicist at the Brazilian Center for Research in Physics in Rio de Janeiro. “People argued you can’t see them because they are actually equivalent to bosons and fermions.” In 1971, that argument seemed to triumph.
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Three physicists – Sergio Doplicher, Rudolf Haag and John E. Roberts, known as DHR – showed that, in a three-dimensional world, any theory of paraparticles could be recast as ordinary standard-model physics in disguise. Space itself would force paraparticles to behave as either fermions or bosons, and their verdict soon hardened into textbook wisdom: paraparticles were a fun idea, but not real. Still, some were undeterred. In the 1980s, Nobel laureate Frank Wilczek showed that particles confined to two dimensions – as they can be within thin layers of materials – could indeed obey different rules. He called them “anyons” and they were a remarkable challenge to the accepted orthodoxy. “When I first proposed anyons, I thought of it as just kind of a lark and a curiosity,” says Wilczek. “But soon they turned up experimentally.” Not as free-floating fundamental particles, however. Anyons emerge in certain materials and are known as “quasiparticles” – collective disturbances that behave like particles. A phonon is a simpler example. It is essentially a packet of sound, produced by atoms vibrating in a material, rather like a Mexican wave travelling through a packed stadium. No single person is the wave, yet the wave moves as if it were an object in its own right. Still, anyons are now taken seriously as possible building blocks for fault-tolerant quantum computers. An experiment in 2024 showed how swapping them around allows information to be stored in a form that is more resilient to errors. But anyons looked like a special loophole to the rule DHR had established: exotic and useful in the laboratory, but nowhere close to a rebuttal of the standard model’s grand binary. In three dimensions, making paraparticles work is quite a bit more difficult. In 2021, Toppan tried to introduce a different type of algebra for describing paraparticles in the laboratory. With this maths, he found that ordinary space no longer forced paraparticles to collapse back into fermions or bosons. The trick was to stop looking at particles one by one. On their own, they could still pass for ordinary particles, but in groups their shared quantum state carried an extra mathematical fingerprint, unique to paraparticles. But serious problems remained. For bosons or fermions, swapping two identical particles in a wave function doesn’t mean this has to happen in the real world. No one is dragging one electron around another. Instead, you are just changing the labels: the particle called A is now B, and vice versa. Since electrons are identical, nothing measurable should change.
“ When I first
I thought of it
a curiosity.
But soon they
turned up”
Paraparticles seemed different. Swapping their labels also changed something else: their hidden states. Even if it is unclear what that physically corresponds to, the relabelling seemed to have real consequences. Now, put one paraparticle on Earth and another on Pluto, and you’ll find that swapping their labels violates a principle known as “locality”, which says that distant objects can’t influence one another instantaneously. But a solution to this once-fatal problem has recently come to light. Zhiyuan Wang, then a PhD student at Rice University and now at the Max Planck Institute of Quantum Optics in Germany, was stuck indoors during a covid-19 lockdown and was entertaining himself with maths. “It’s kind of funny,” says Hazzard, his colleague and former supervisor. Wang’s response to lockdown boredom was “playing around with representations of algebra”. But when Wang showed him his calculations, Hazzard was immediately intrigued. Using a similar but extended version of Toppan’s algebra, Wang and Hazzard tied the mathematics of re-labelling particles back to physical motion. In a paper published in 2025, they showed how a swap could change a paraparticle’s hidden states only if the particles
proposed them,
as a lark and
STEPHAN SCHMITZ
were actually exchanged by moving one around the other. This process would take time, so wouldn’t allow for a faster-than-light signal. “It’s an absolutely brilliant paper,” says Toppan. Wilczek describes the finding as “interesting” and “intriguing”, but says more theory is needed. Wang and Hazzard have shown how paraparticles behave when exchanged, but not the full story of how they move or interact with one another. “Anyons are different in that we can keep track of the whole history of how particles have moved,” he says. Even so, Wang and Hazzard’s work suggests that paraparticles could exist as quasiparticles that can exist in higher dimensions than anyons. “New types of quasiparticles may give us materials with properties that we just didn’t realise were possible,” says Hazzard. Materials hosting paraparticles could conduct heat or electrical charge in new ways, for instance. Wang also thinks there could be interesting applications in secret communications. Imagine two parties wanting to exchange information without sending a conventional signal that could be intercepted. In principle, swapping paraparticles might allow information to be encoded in their exchange without leaving the same kind of measurable trace. While the possibility of new quasiparticles could unlock technologies, the bigger prize lies elsewhere: paraparticles not just inside materials, but as a new type of fundamental particle. “The idea that these could be fundamental particles is extremely speculative. It seems a little bit of a desperate idea,” says Hazzard. “But when you talk to people in the community of finding new fundamental particles, it turns out we’re a little desperate.” No one yet knows quite what role such particles would play, or how they would interact with the particles we already know. But they would almost certainly behave unlike anything in the standard model. Bosons are happy to crowd together, while fermions are barred from doing so. Paraparticles would obey a stranger rule of togetherness: not quite free to pile up, but not quite forbidden from overlapping. They would introduce a new way for particles to share the universe’s quantum real estate. One especially tempting problem to apply them to would be the mystery of dark matter. We know that galaxies are wrapped in vast halos of unseen matter, but we still don’t know what this is made of. Hazzard has already begun exploring whether paraparticles could fit the bill with cosmologists Andrew Long and Mustafa Amin, also at Rice University.
ESA
They say that the inability of fermions to share the same quantum state imposes a limit. “If the mass of the dark matter particle is below about 1/500,000th of the electron’s mass, then dark matter cannot be made of fermions,” says Long. Very light dark matter candidates – such as the hypothetical particles known as axions, which interact very weekly with ordinary matter and light – are usually treated as bosons for that reason. But Amin realised that the new social rules of paraparticles could allow them to be light enough to form dark matter halos. The idea is still preliminary, but it is an intriguing proposition. “I think people who work on dark matter would be very receptive to the idea that there’s a whole new knob to turn,” says Long.
Strange behaviours
Demonstrating that paraparticles exist won’t be easy. Their defining hidden states can’t be measured directly. Instead, physicists must look for them indirectly. Toppan has recently proposed one such test. Imagine two scientists monitoring a pair of particles before and after they are exchanged. For ordinary bosons or fermions, the measurements should match perfectly. For paraparticles, the hidden states would subtly alter the underlying wave function, creating a telltale asymmetry in the data even though the particles themselves still appear identical. Hazzard and Bryce Gadway at Penn State University hope to look for this effect in paraparticle-like states in chains of ultracold atoms. It wouldn’t amount to the discovery of a fundamental paraparticle, but
The neutrons that fill neutron stars are fermions, one of the two traditional particle types
it would show that their strange behaviours can emerge in a real physical system. Finding a fundamental paraparticle, on the other hand, would be an even taller order. One possible route to this is through particle accelerators. “What you’d do is accelerate some particles, create a cascade reaction and then observe the outcomes,” says Vedral. That means smashing particles together, letting the collision spray out new particles and then looking for patterns in the debris. In principle, paraparticles could carry the imprint of hidden states changing as particles swap places. But there might be a way to see evidence in data we already have. If paraparticles contribute to dark matter, dark energy or other cosmic phenomena, their fingerprints might already be hiding in observations of the universe. Vedral and others have suggested looking for their influence in the cosmic microwave background, the relic radiation left over from the big bang. “One of the possibilities is that there is a contribution from some kind of paraparticle interactions,” he says. Kasia Rejzner at the University of York, UK, says this is “the simplest, cheapest way to look for them”. For now, paraparticles remain a mathematical possibility rather than a physical reality. Much is still unknown, including their mass, spin and full dynamics. Wang and Hazzard are now working to place them within a fully relativistic quantum field theory, the language of modern particle physics. Whether that effort reveals a new kind of particle or closes the door once again remains to be seen. But if paraparticles survive such efforts, they may change the standard model in ways we can barely imagine. There is even the possibility, says Hazzard, that some particles we already know as fermions or bosons might reveal paraparticle-like behaviour if measured precisely enough. “Some people have reached out to us saying: ‘How well do we know the electron actually is a fermion?’ ” he says. It is a revealing question. Physics can sometimes see reality in black and white. But paraparticles are a vital reminder that nature’s cleanest divisions are often places to look again. ❚
Miriam Frankel is a science journalist based in London
ASHLEY COOPER/SCIENCE PHOTO LIBRARY
D
EEP under your feet, Earth is hot. Really hot. Some of that heat is left over from the planet’s violent formation. More is continually created by the splitting of radioactive atoms in the rocks below. In a few places, Earth’s hidden furnace dramatically makes itself known, bursting through the crust as volcanoes, geysers and rivers of magma. Spectacular stuff, but also extremely useful – if we can get at it. Conventional geothermal power works best wherever geology has done the hard work for us: where fault lines crack the crust and hot water or steam rises close to the surface. That’s why countries like Iceland, New Zealand, Kenya and Indonesia can turn Earth’s heat into warmth for homes and electricity for grids, while much of the rest of the world has barely touched it. Its appeal is obvious. Unlike solar power, geothermal doesn’t fade when the sun sets, and unlike wind power, it doesn’t stall when the air is still. Over the past decade, advances in drilling have begun to loosen geothermal power from its geological shackles. Some projects aim to improve on nature, creating cracks and pathways where none existed. Others are more ambitious still: they want to drill so deep that geothermal power could work almost anywhere. “Ultimately, the whole world is the goal,” says Matt Houde, co-founder of geothermal energy company Quaise Energy. That would turn it from a niche resource into something far bigger – a way to tap the planet’s hidden heat wherever we happen to need it. To convert heat from Earth’s interior into usable energy, engineers pump cold water into naturally occurring reservoirs in hot rock. There, it warms up and returns to the surface
Iceland gets lots of its energy from geothermal
as hot water or steam, which can be used to drive turbines and generate electricity. The water is then sent back underground to begin the cycle again. It’s a simple concept, and unlike fossil fuels, geothermal heat sources are practically inexhaustible on human timescales. “If you measure in terms of the energy stored within the Earth’s crust, geothermal heat exceeds by orders of magnitude all hydrocarbons,” says Houde. The trouble is that traditional geothermal requires three ingredients to work: heat, water and rock that is permeable or fractured enough for water to move through it. “Traditional geothermal systems are very constrained to countries and regions within countries where you have this unique combination of conditions,” he says. That is why geothermal has flourished in places like Iceland. Sitting astride the mid- Atlantic ridge, the country has those core ingredients in unusual abundance. The global oil crisis in the 1970s pushed Iceland to exploit that advantage, and geothermal now makes up over a quarter of the country’s electricity supply. That may not sound like much, but Iceland’s geothermal plants can keep generating whatever the weather, making them a steady backbone for the grid. “Geothermal is really well placed to be the glue that will make low-carbon electricity systems work,” says Iain Staffell, a sustainable energy expert at Imperial College London. However, most countries don’t share Iceland’s good fortune. They may have heat or water or fractured rock, but not all three at depths that are easy to reach. Traditional geothermal plants are limited to mining heat from less than 2 kilometres underground.
energy stored in Earth’s crust, geothermal heat exceeds by orders of magnitude all hydrocarbons”
DIETER TELEMANS/PANOS PICTURES
Go much deeper, and the engineering becomes brutal. Drills must chew through hard, hot rock. The vertical shafts that connect the surface to heat reservoirs, known as wells, must survive punishing temperatures and pressures. Even after all that, the rock may still be too tight and unbroken for water to flow through it. Still, the prize is enormous. The International Energy Agency estimates that geothermal’s technical potential is around 150 times current global electricity demand, assuming we can exploit heat down to about 8 km. Conventional geothermal typically taps pre-existing reservoirs of hot water or steam in permeable, fractured rock less than 2 km underground, leaving much of that potential out of reach. The implication is clear: to expand the resource, engineers must drill deeper – and create the underground plumbing that nature hasn’t provided. The first of the new geothermal techniques does exactly that. Enhanced geothermal systems (EGS) target hot but impermeable rock, typically 2 to 10 km underground. Engineers pump in hot water at high pressures to open or widen fractures and create pathways for fluid to circulate (see “How geothermal is breaking new ground”, right). This is the most mature technology in geothermal’s new era. But this approach has a downside. Forcing water into deep rock doesn’t just create useful cracks. According to a 2023 review of the research, it can also disturb older, pre-existing faults that are already
At Iceland’s Blue Lagoon, Earth’s heat warms natural lagoons and is extracted to heat homes
really well placed to be the glue that will make low- carbon electricity systems work”
under strain. Many faults are held still by friction, like a heavy book resting on a tilted table. Pump water into them, and the pressure in their pores and fractures rises. That helps to prop the two sides of the fault apart, reducing the force clamping them together. If the fault was already close to slipping, that can be enough to induce an earthquake.
Slowly does it
An investigation commissioned by the South Korean government concluded that a nearby EGS project triggered a magnitude-5.5 earthquake in the city of Pohang in 2017. More than 80 people were injured and the earthquake caused an estimated 300 billion Korean won (£148 million) of damage, making it the most destructive in the country’s history. Bill Ellsworth at Stanford University in California was part of the team that helped establish what role the geothermal plant played in the disaster. “In Pohang, they drilled a couple of wells that were a long way apart,” he says. The hope was that pumping water into one would fracture the rock enough to connect with the other, creating a route for water to pass between them and gather heat. But trying to force that kind of connection through the subsurface is risky, particularly if the drilling intersects faults that are already primed to slip. That is why newer projects are trying to be more deliberate, says Ellsworth. In Iceland, for instance, engineers try to create EGS reservoirs more gently by pumping cold water slowly and at relatively low pressure. Over months, the cooling rock contracts and cracks, says Lilja Magnúsdóttir, executive vice president of resources at Icelandic energy company HS Orka. Iceland also has an advantage born of necessity: it is a seismically restless place, so the country has already invested heavily in monitoring. At HS Orka, that now includes using geothermal wells themselves as early- warning sensors. When magma begins to move, it compresses the surrounding rock, creating a telltale signal in the well. “It’s a really cool design,” says Magnúsdóttir. But even where EGS projects have learned to manage seismic risk, hard rock still makes an unreliable basis for a plumbing system. Fluid can leak away and contaminate groundwater, for instance. And the same fractures that make the system useful can also make it dangerous. One way around this is to stop asking the rock to carry water at all. Where natural fractures and reservoirs don’t exist, an alternative to EGS is to drill a sealed loop through hot rock. Engineers drill down,
then sideways, until the boreholes connect underground, before lining and sealing them with steel and cement. That creates something like a buried radiator where fluid circulates, but never comes into contact with the rock itself. This closed-loop system is known as an advanced geothermal system (AGS), and it has been tested successfully in Germany, where Canadian energy company Eavor has developed a geothermal power plant at Geretsried, which began construction in 2022 and started producing electricity last year. Because closed-loop systems don’t force fractures open in the rock, they should reduce the risk of induced earthquakes. And because they don’t depend on continually pumping water into and out of those fractures, they should reduce it further still. There is another possible advantage. If the working fluid stays inside a sealed
Advanced geothermal
How geothermal is breaking new ground
Enhanced geothermal makes its own underground cracks, closed-loop systems act like buried radiators and superhot rock projects drill to extreme depths. Together, they show how engineers hope to take geothermal energy beyond the rare places where nature has already done the plumbing.
Enhanced geothermal
Cold fluid in
Closed-loop pipe network pipe network
Hot fluid out
Induced fissures Induced fissures
pipe, it doesn’t have to be water. Companies can, in principle, use fluids that pick up and release heat more efficiently. Eavor’s working fluid is a company secret. The firm China Huaneng Group, meanwhile, has built the first geothermal demonstration plant that uses supercritical carbon dioxide – CO2 that is compressed and heated until it becomes not quite a gas and not quite a liquid. In that state, it is dense and flows easily, and is very good at moving heat. The company’s test facility began operating in May this year in Zhengzhou, China. But these systems have their own difficulties. Eavor has had to scale back the number of wells it planned to drill after rock debris clogged parts of the pipe network. Its plant works, but not yet as efficiently as hoped. That points to a broader question: can closed-loop systems circulate enough fluid, and draw heat from the
2–7 km for enhanced and advanced advanced geothermal systems
~10 km or more for superhot rock geothermal systems
Super-deep geothermal
rock fast enough, to be commercially useful? “The jury is still out,” says Ellsworth. “Time will tell whether these ideas of having just a single closed loop will be actually successful.” And while AGS could be safer and cleaner than inducing fractures deep underground, it is still limited to places where hot rock lies within reach, usually a few kilometres down. To make geothermal truly global, companies will have to drill much, much deeper. The deeper you go, the hotter Earth gets. Go deep enough and water crosses a strange threshold. At about 374°C (705°F), under sufficient pressure, it transforms into a supercritical fluid – akin to the CO2 in the China Huaneng demonstration plant – and can carry far more heat than ordinary hot water or steam. “There are a few countries where geothermal does provide a sizable mix of the energy supply. But strictly the heat itself, which is fundamentally what geothermal energy is, is actually available anywhere if you go deep enough,” says Houde. Supercritical temperatures are usually found at depths of at least 5 to 20 km, and often deeper. The rocks become harder the further you go: basalt or granite rather than the softer sedimentary layers often found closer to the surface. This rock chews through even the hardest tungsten carbide or diamond drill bits. Then there’s the time spent not drilling at all but instead replacing worn-down drill bits or equipment that begins to fail at higher temperatures and greater depths. These delays quickly push up costs, says Houde.
Quaise, which is based in Houston, Texas, wants to get around this by drilling in a different way – without using a drill bit at all. Its plan is to use conventional drilling for the upper part of the well, then switch to high-powered microwave energy once the rock becomes too hard. The hole would be lined with corrugated steel, helping the microwaves travel downwards. When that energy hit the rock, it would heat it until the rock cracked, broke apart or even vaporised. “There’s no drill bit mechanically destroying the rock here, it’s just the interaction of the energy with the rock,” says Houde. The rock would be reduced into a fine ash that is purged from the well with a nitrogen- rich gas and collected at the surface. Quaise isn’t alone in pursuing non-contact drilling: Slovakia-based GA Drilling is also trialling laser- and plasma-based systems, and carried out its first field tests in 2023.
ALESSIA PIERDOMENICO/BLOOMBERG VIA GETTY IMAGES
Once the hole is open, Quaise wants to create a deep, EGS-style reservoir. Water would be sent through fractures in superhot rock, picking up heat before returning to the surface to generate electricity. In principle, it is geothermal freed from geography. Quaise’s test holes are still just a couple of kilometres deep, but the company sees them as a proof of concept for something much larger. Its first planned superhot geothermal plant, located in Oregon, is intended to come online by 2030, accessing temperatures up to 400°C (752°F) at a depth of 3 to 5 km. A potential future site would push deeper, potentially to 10 km. “By 2035, we want the first superhot well producing energy at a depth greater than 10 kilometres,” says Houde, who thinks his company’s technology could transform any region into geothermal country. But there are still serious uncertainties. One is whether such deep wells can be kept open under the immense pressures found kilometres below ground. “It’s unclear whether that is possible,” warns Ellsworth. Houde accepts that the hardest engineering lies ahead. “I think it’s very viable for getting to these initial depths to prove superhot geothermal,” he says. “I think it’ll become increasingly more challenging to push the frontier on how deep we can go.” Iceland offers a glimpse of how these different strands of geothermal might converge. Instead of simply resting on its laurels as one of the world’s geothermal success
stories, the country is fast becoming a test bed
for what comes next, says Magnúsdóttir.
Its deepest geothermal well – the second by
the Iceland Deep Drilling Project, a consortium
of the country’s leading energy companies
and its energy authority – has already brushed
against the promise of superhot geothermal.
It was completed in 2017 and goes down
4.7 km. “It is the first well in the world where
supercritical conditions were confirmed in the
geothermal well,” says Magnúsdóttir. Icelandic
operators are also using EGS techniques to get
more from existing fields, stimulating deeper
faults to reach another kilometre or so of heat.
QUAISE ENERGY
Quaise Energy uses microwave energy to cut through hard rock found deep inside Earth
A worker surveys the interior of a geothermal cooling tower in Italy
drilled that hole in the ground, that lasts for over 100 years”
Next year, the Iceland Deep Drilling Project plans to drill its third well. “There, they just have to go down to a little over 2 kilometres to reach supercritical conditions,” says Magnúsdóttir. But even at that relatively shallow depth, the engineering challenges remain fierce. The main problem is well integrity. At such high temperatures, the steel casings that line the well can expand, deform and fail. In Iceland, engineers have been testing fixes, including flexible connectors between sections of casing. This sort of engineering will be crucial if geothermal is to win over investors. Projects are expensive up front and slow to prove, and often need permits before developers know whether a site will work commercially. But the reward for patience can be unusually durable. “It’s very, very costly,” says Sanjeev Kumar at the European Geothermal Energy Council. “But once you’ve drilled that hole in the ground, that lasts for over 100 years.” That is the promise and the problem in miniature. “We know that very deep geothermal energy would be fabulous if we could reach it,” says Ellsworth. “We just don’t yet know if it’s possible.” ❚
Katharine Sanderson is a science journalist specialising in the physical sciences
F
KLAWE RZECZY
in our social lives”
What makes a country happy? As editor of the latest World Happiness Report,
Jan-Emmanuel De Neve tells Alexandra Thompson what we can learn from the nations where people feel the most content
INLAND is starting to sound like a nirvana. A few months ago, it was named the happiest country in the World Happiness Report, topping the chart alongside its Nordic neighbours, which occupy five of the top six spots. This was no fluke – Finland has now come first for nine years in a row. Ostensibly, there are plenty of factors that ought to make people in Nordic countries less than content, not least the dingy weather and high taxes. Then again, there is a sense that these taxes really go somewhere, with residents reaping the rewards of investment into healthcare, education and transport. Plus, the low population density, massive
forest coverage and access to lakes and coastlines all mean that even city dwellers are never too far from nature. But how much confidence should we place in these global rankings? After all, happiness is a slippery concept, and all sorts of factors – not least how different cultures understand what it means to be happy – could conceivably skew the results. To delve into these questions, New Scientist spoke to economist and behavioural scientist Jan-Emmanuel De Neve at the University of Oxford, the editor of the World Happiness Report. He explained how his work attempts to measure true happiness, why he believes
Finland deserves its top spot and what the rest of us can do to bring a bit more joy to our everyday lives.
Alexandra Thompson: How do you define happiness – an incredibly easy and straightforward question, I’m sure. Jan-Emmanuel De Neve: It is a question that has been top of mind for philosophers for 2500 years, from Aristotle and beyond. I think there was a bit of a step change in the 1980s, when psychologists started defining well-being as subjective well- being, which is, ultimately, how people feel about their lives. The long story short is we now bypass the philosophical debate and rather ask people directly: “Are you happy with your life?” That means I’m not imposing a definition of what well-being is. Instead, I’m going straight to you and asking: “Are you leading a happy life in your own mind?”
The 2026 World Happiness Report recently came out. How do you decide the rankings of different countries? We use a survey that is part of the Gallup World Poll, which runs annually and covers almost 150 countries. In every country, they have a sample of 1000 people at minimum, who represent it quite well in terms of gender, socioeconomic status, urban versus rural dwelling and so on. We start with subjective well-being, asking people to visualise a ladder with 10 rungs, with the top rung being the best possible life you can imagine and the lowest rung the worst possible life you can imagine. We then ask: “Where do you think you stand today?” That gives us a score from 0 to 10. This isn’t a measure of whether people are dancing in the streets or singing from the rooftops – it is a sense of contentment. The annual rankings are then based on a moving average over the past three years. Then the science kicks in. We reverse- engineer the results to see what might explain the differences between countries using objective measures, like GDP per capita, healthy life expectancy, whether people have friends they can rely on, etc. We also use surveys to measure things like generosity and whether people in these countries generally feel positive or negative emotions.
Finland, work-life balance is taken much more seriously, so people actually have time for rich social lives”
Nordic countries make up five of the top six spots in the report, whereas the US ranks 23rd and the UK ranks 29th. What are Nordic countries doing so right? For one, they have high levels of economic productivity. But unlike many other high- income nations, wealth is more distributed, so income inequality is much lower than in places like the US. And we know, based on previous research, that greater income inequality is associated with worse well-being, all other factors being equal. The second point is that money gets distributed through a welfare state, which minimises economic anxieties and establishes social safety nets. Being made redundant or being unemployed will feel very different in the US versus Finland. Then there’s also a notion of healthy life expectancy in these countries, which measures the years people can expect to spend in good health, not just lifespan.
RAGNAR TH SIGURDSSON/ARCTIC IMAGES/ALAMY
What is most underrated is the importance of social ties. Our research correlates happiness with proxies like the number of shared meals you have a week and whether you have friends you can rely on in an emergency. People in these countries also have more time for family and friends than one might have in the UK or the US, where work devours most of our waking hours. Over in Denmark or Finland, work-life balance is taken much more seriously, so people actually have time for rich social lives. They also have high levels of social trust. We see this through the “lost wallet” question, which asks: “If you lost your wallet, what is the likelihood that you think you would get it back?” We find that in Nordic countries, people expect wallets to be returned much more frequently than they do in other places. That feeds positively into their well-being.
How do we know if a high level of social trust causes greater happiness or is a consequence of it? This is the chicken-and-the-egg problem, but it is actually both. If you are in an environment where there is lots of trust, that will drive your well-being. And when people are happy, they are more pro-social. Look at volunteering: people who volunteer are happier, and if you are happier, you are more likely to volunteer. It is a synergistic, dynamic relationship, with arrows going in both directions.
Investing in face-to- face relationships is vital for happiness
IGOR SOKOLOV/ALAMY
What sets Finland apart from other Nordic countries? It has taken the number one spot in the report for the past nine years. I think there are two elements that set it apart. Finland has a small population in a vast country, and everyone seems to have a cabin on a lake somewhere in the woods. So, that connection to nature is very present, and it is well-documented that spending time outside enhances well-being. It improves mood, reduces stress and lowers blood pressure – the list goes on. The fact that most people in Finland are content with their lives suggests they may be more down-to-earth than those in other Nordic countries. They aren’t wishing for the stars; they are pleased with what they have, and that positively influences their subjective well-being.
It is surprising that Finland ranks so high, given it has some of the shortest winter days in Europe. Have you looked into the effects of this? While Finland may have some of the shortest days in the winter, that comes with the corollary of having some of the longest days in spring and summer. They have also turned the seasons into something special. So, in the winter, they make their homes cosy, and then in the summer, Finland explodes with life and they take full advantage of their lakes and forests.
How do you account for cultural differences when interpreting these survey results? In Denmark, for instance, contentment is part of the national identity, whereas in the UK, there is the famous mantra “keep calm and carry on”. In every culture, there are quirks and social psychologies around what is expected and what isn’t. We try to get around these issues by taking a step back and asking people to evaluate their quality of life on a ladder. So, it is
more holistic than just asking if they are happy. There are subtle linguistic differences in how well-being is translated and interpreted across cultures, as well. But these linguistic differences aren’t drastic enough to overrule the variation across countries in terms of what constitutes a good life. We have also evaluated the effects of migration in past reports and found that if someone moves to another country, it is surprising how quickly they adapt to its average happiness. So, if somebody from the UK moves to Canada, they start slightly lower and then you see them pick up quite quickly towards the average in Canada, and you see that in the inverse direction as well. So, it isn’t just a case of cultural expectations. It shows that the environment in which people live matters a great deal.
Costa Rica came fourth in the report, which is the highest a Latin American country has ever ranked. It is a big improvement from its 23rd position the year before. What explains this jump? If you look at the population indicators around health, life expectancy or GDP, Costa Rica is punching above its weight in terms of well-being. I suspect that is partly because of the strong social relations people have there. It shows that there is more to life than just wealth or GDP per capita. Costa Rica actually ranked relatively high between 2012 and 2015, then fell for unknown reasons, and is now making its way back up. That may partly be because other countries have come down, but it also has political stability and a thriving ecotourism industry. It is impressive to see.
Based on your research into happiness, what are the biggest changes you would
Nordic countries tend to come out top in global lists of happiness
OLIVIER BOURGUET/ALAMY
like to see to help people feel more content? It varies hugely between countries. The biggest well-being bang for one’s buck comes through policy. In the UK, we think so much about physical infrastructure, and that is important, but what about social infrastructure? Can we invest more in communities and enable them to come together, whether that is through bridge clubs for older people or local football pitches for people out in the countryside? I also think we could start redistributing the economic gains in productivity that come from new technologies, like AI, by having a four-day working week with five-day pay, for example. The World Happiness Report will look more closely at how effective this is in 2027. We are expected to do so much throughout a working day, but our brains are the same brains as those 1000 years ago, so people feel stressed and under pressure. There are several policies that could really improve well-being without costing the world.
Until such policies are in place, what can we as individuals do to feel more content, maybe by adopting some tips from Finland? Invest in face-to-face relationships; meet people for lunch. We need to invest more in our social lives. This is a particular concern for people who work from home full-time. If you are a hybrid worker, try coordinating your time in-office so you are spending quality time with colleagues. Infrastructures like video call software are very helpful, but it seems to undermine face-to-face relationships. It is a knife that cuts both ways, and we need to be mindful of that. ❚
Alexandra Thompson is an assistant news editor at New Scientist focused on health
A
growth spurt
a similar size to us, but they were actually much smaller, finds Michael Marshall
S SOMEONE who writes a lot about human evolution and archaeology, I’ve seen a great many artists’ impressions of prehistoric people. Some are remarkably believable, closely tied to scientific findings as much as possible. Others, not so much. I twitch every time I see a reconstruction of an African or tropical hominin with northern-European- style pale skin, and the twitches escalate whenever I see hairless hominins wandering around naked in temperate regions like Britain. Put something on or you’ll die. However, the thing that has come to bother me most is that a lot of our images of prehistoric people are just too big. Sometimes, this is about musculature. You can find pictures showing prehistoric people (generally men) with ripped physiques, muscles bulging, as if they’ve been doing reps at the gym and downing protein shakes. This just isn’t how practical everyday fitness works. If your body looks like a movie superhero’s, that is a cosmetic choice – one that is achieved using physiological trickery, like artificially dehydrating yourself so your muscles stand out. Genuine speed, strength and endurance don’t look like that. Beyond these surface aesthetics, there is also a deeper issue. Prehistoric people were smaller than us, both in body mass and in stature. At the extreme end of this, we have the truly diminutive groups like Homo floresiensis (known as “hobbits”), but even our direct ancestors were probably, on the whole,
on the small side compared with people today.
The story of how humans got heavier and
taller is slowly coming together, as our fossil
collection expands. And it looks like it was
an important part of our origins.
To find out how hominin body size has
changed over time, I spoke to evolutionary
biologist Jacob Gardner at the University
of Reading in the UK. He is lead author
of a study published in PNAS last month,
which looks at the trends in body size
over the past 4 million years.
Let’s start by putting some concrete
numbers on this. Earlier hominins like
Ardipithecus and Australopithecus, which lived
earlier than 2 million years ago, had an average
body mass of 40 kilograms, with a range of
30 to 50 kg. Homo habilis, an early member
of our genus, was a bit bigger: 45 kg on average,
ranging from 35 to 55 kg. Homo erectus, the first
hominin known to have migrated out of Africa
into Eurasia, was bigger still, averaging 60 kg
with a range of 50 to 75 kg. Finally, prehistoric
Homo sapiens were up to an average of 75 kg
and a range of 55 to 80 kg.
Gardner and his colleagues compiled
estimates of body mass for 386 specimens
belonging to 21 hominin groups, dating from
4.5 million years ago to 30,000 years ago. If
that seems a little arbitrary, there are reasons
why. They excluded more recent specimens
because there is evidence of our species having
shrunk in the past 30,000 years, which would
have made a mess of the analysis. They also left
out the earliest hominins, Sahelanthropus and Orrorin, because of ongoing uncertainties over how they are related to later groups. The team then ran 1000 models to see what would best explain the data. Did body size increase within each group, meaning earlier H. erectus were smaller than more recent ones? Or did each group pretty much stay the same size, with the changes coming when new groups evolved? Did body size increase gradually over the whole 4.5-million-year timespan, or were there long periods of stasis and occasional bursts of growth? The researchers ultimately identified two trends, which between them explained most of the changes. The first was “the gradual progression from Ardipithecus to later hominin species”, says Gardner. This was a “modest” increase in body mass of about 1 to 3 kg per million years. If you remember, average body mass went from 40 kg to 75 kg in 4.5 million years: this gradual increase can only explain about a third of that. Hence the second trend, which was a “big jump around the appearance of Homo erectus and other later species in our genus Homo”, says Gardner. The first H. erectus appeared in Africa around 2 million years ago. We’ll get to why this might have happened in a minute, but first let’s look at what happened to people’s height.
Ripped physiques are more of a modern phenomenon
CHUANG ZHAO
SHUTTERSTOCK
Gardner and his colleagues didn’t
analyse height, but a team led by Manuel
Will at the University of Tübingen in
Germany did in a study published in
Royal Society Open Science in 2017. This
one compiled 204 stature estimates from
4.4 million years ago until nearly the present
day. The variation is dramatic. One especially
dainty Australopithecus specimen clocked
in at just 105 centimetres, while a 24,500-year-
old H. sapiens from Barma Grande cave
in Italy was almost 189 cm tall.
Will’s team found “phases of relative stasis
intermitted by periods of rapid increases”.
Before 2.2 million years ago, most hominins
were less than 140 cm tall. There was then a
noticeable increase between 2 million and
1.6 million years ago. By 1.6 million years
ago, some individuals grew taller than
170 cm for the first time. However, such
heights only became commonplace much
more recently, around 500,000 years ago.
This loosely maps onto what Gardner’s team
found. Hominins got significantly bigger, both
in mass and in height, from around 2 million
years ago when H. erectus came on the scene.
What was going on? The answer,
as usual, is “lots of things”.
One factor may be sexual dimorphism.
In early hominins like Australopithecus, males
were significantly bigger than females – 170 cm
compared with as little as 105 cm – and had
larger canine teeth. We see the same pattern in
chimpanzees and other animals where males
jump in size around the appearance of Homo erectus”
compete violently for females, with successful males mating with multiple females while unsuccessful males don’t mate at all. But in early Homo species, males and females were much more alike (and in H. sapiens today, the height and mass differences are smaller still).
Tall tales
Exactly how this played out is unclear. “There’s some hypotheses that perhaps males got smaller through time, and then there’s hypotheses that it’s the females that got bigger through time and the males stayed about the same,” says Gardner. If the latter is true, that would account for some of the average increase. Diet may also have played a big role. Early Homo ate more meat than Australopithecus, and meat is calorific. Furthermore, “we are finding some of the earliest evidence of cooking meat in Homo erectus”, says Gardner. Cooked food contains more calories than raw food, so this was another way of getting more nutrition from a given food source.
Homo floresiensis was barely more than 100 centimetres tall
Cooked food may also have been a factor
in another important change in our bodies:
the growth of our brains. The extra calories
from cooked food may have enabled our
brains to evolve to be larger.
It is also crucial to bear in mind that different
hominin groups evolved in different ways,
depending on their circumstances. So while
there was this overall tendency to get bigger,
not everyone did. H. floresiensis, who lived
on Flores in Indonesia until just 50,000 years
ago, were barely more than 100 cm tall.
Homo naledi from South Africa, who lived
335,000 to 236,000 years ago, were taller but
still not much more than 140 cm. One of the
shortest known adult hominins was a female
Paranthropus robustus, who was probably just
103 cm. We don’t know why these hominins
became so small, and it may be that each
one did so for different reasons.
“All these different species are finding
their own evolutionary path,” says Gardner.
Each hominin group had its own unique
set of environmental contexts, and this was
reflected in their varying body sizes, he says.
Finally, let’s turn the question around.
Once early Homo groups like H. erectus
evolved larger bodies, how did that change
their lives? “The larger you are,” says Gardner,
“the longer the strides you can take across the
landscape.” That is especially true of H. erectus,
whose legs were proportionately longer
than those of earlier hominins. Gardner
suggests they had larger home ranges than
previous groups.
This may even help to explain why
H. erectus were the first hominins (that we
know of) to roam outside Africa. That is a
long-standing puzzle: how come they travelled
all the way to Java, when earlier hominins
seemingly never left Africa? If Gardner is right,
it may be partly because they were bigger,
so they needed more room. ❚
This is an extract from our subscriber newsletter Our Human Story, written by science writer Michael Marshall. Sign up at newscientist.com/our-human-story
ACROSS 7 Benchmark (8) 9 Joseph ___ , English botanist, friend of Charles Darwin (6) 10 S-shaped device used in architecture, woodworking etc (4) 11 Term for highly responsive muscle fibres (4-6) 12 Abrasive tool (6) 14 Scaly anteater (8) 15 Steam turbine component (7,6) 17 Flexible tube for draining fluids (8) 19 Lion or tiger, say (6) 21 Bamboo-eating mammal of China (5,5) 22 Simple programming command (2,2) 23 Active participants, components, etc. (6) 24 ___ Avenue, Brixton thoroughfare formerly notable for its lighting (8)
6 2
2 4
DOWN 1 Part of a flower’s reproductive organ (6) 2 On a single occasion (4) 3 Anticoagulant medication (8) 4 Massless particle (6) 5 At 90 degrees to the vertical (10) 6 Chain ___ , self-amplifying sequence of events (8) 8 Act or instance of vanishing (13) 13 Toxic alklaloid found in plants such as larkspur (10) 15 Components designed to reduce friction between moving parts (8) 16 Blown up (8) 18 Keyboard operator (6) 20 ___ acid, HNO3 (6) 22 Logic ___ , device that might be NOT, AND or NAND (4)
zone
Cryptic crossword next week
set by Sam Wong
1 What chemical with the formula C5H9N3 triggers immune responses in the body?
2 A quantum computing algorithm that could be used to break current encryption standards is named after which researcher, who developed it in 1994?
3 On which island in South-East Asia were fossils of a small ancient hominin species discovered in 2003?
4 What is the name of Earth’s first geologic aeon, which lasted from 4.6 billion to 4 billion years ago?
5 Which physicist wrote the 1944 book What Is Life?, which pondered: “How can the events in space and time which take place within the spatial boundary of a living organism be accounted for by physics and chemistry?”
Block Universe created by Puzzlr
The goal is to divide the grid below into non-overlapping rectangles. Each rectangle must contain exactly one number, and have an area equal to that number. For example, a 6 should be in a rectangle covering six squares.
2 3 3
4 4 6 3
6 3
6 3 4
2 3 5 2
3 4 2 3
3 2
now playable online newscientist.com/games
Clear the air
Is it true that fresh air heats up faster than stale air? And, if so, why?
Simon Lee
School of earth and
environmental sciences,
University of St Andrews, UK
Air usually seems “stale” if it
contains elevated levels of carbon
dioxide (from human respiration)
and odour, neither of which
affects how quickly it heats up.
However, stale indoor air is
often (though not always) more
humid than fresh, outside air.
Humid air has a slightly higher
heat capacity than dry air, so it
requires marginally more energy
to warm. In practice, though, the
difference is too small to notice,
especially as the difference in
humidity between indoor and
outdoor air is often modest.
Ventilation can improve air
circulation, helping heat from
a radiator spread more evenly.
If condensation has formed
in the room, much of the heat
supplied initially goes into
evaporating this moisture, rather
than raising the air temperature.
Ventilating with drier
outside air helps the room dry
more quickly, so subsequent
“ When soils are dry, less of the sun’s energy is used to evaporate water, leaving more available to heat the ground and air”
heating becomes more effective. A similar process occurs during heatwaves: when soils are dry, less of the sun’s energy is used to evaporate water, leaving more available to heat the ground and air.
Robin Maguire Hobart, Tasmania, Australia We might define stale air as air that has been extensively breathed by people. In that case, it contains a higher proportion of carbon dioxide
This week’s new questions
Bottoms up What is the optimal way to ice a cocktail: fewer big cubes or lots of small ones? Mark Harper, Brighton, UK
Time for bed What is the smallest creature that needs to sleep and what does this tell us about the nature and need for sleep itself? Jim McHardy, Clydebank, West Dunbartonshire, UK
and water vapour than fresh air.
We can see what this
means by comparing the
molar specific heat capacities
of the relevant molecules at
constant pressure – that is, the
amount of energy required to
increase the temperature of
a particular volume by 1 unit.
Nitrogen and oxygen (which
make up over 99 per cent of fresh,
dry air) each have a specific heat
capacity of a little over 29 joules
per kelvin per mole. The
equivalents for carbon dioxide
and water vapour (at normal
temperature and pressure)
are higher, around 37 and
35 J/mol.K respectively.
So, the overall heat capacity of
stale air is rather higher than for
fresh air and therefore fresh air
will indeed heat up more quickly
Want to send us a question or answer? Email us at lastword@newscientist.com Questions should be about everyday science phenomena Full terms and conditions at newscientist.com/lw-terms
than stale air, assuming a fixed rate of energy input. However, the effect is likely to be small. If the overall quality of some fresh air was degraded to the equivalent of a typical exhaled breath (which sounds fairly stale to me), this would result in the air composition changing by the addition of about 5 per cent CO2 and perhaps a couple of per cent water vapour (depending on the initial humidity). This would imply an increase in overall heat capacity of only 1 to 2 per cent. Specific heat capacity increases slightly with temperature, more so for more complex molecules – CO2 relative to nitrogen, for example. As a result, the difference in heat capacity between fresh and stale air will increase slightly as temperature rises. If the ambient
What is the best strategy to keep your cocktail cool: fewer big cubes or lots of little ones?
temperature changed from 0 to 30°C (32 to 86°F), the heat capacity differential would increase by about one-tenth – not enough to affect matters greatly.
Something fishy
The positions of most fishes’ eyes mean they cannot see their own body. So, how do they recognise others of their own species? (cont.)
ALEXANDER SPATARI/GETTY IMAGES
Shelby Temple University of Bristol, UK Humans, and most animals for that matter, have eyes fixed in their heads in a manner that doesn’t allow them to see their whole self. Snails and animals whose eyes are on stalks might be the exception. Therefore, the same question applies to us. Some of it will be innate and some of it will be learned, just like how a baby human sees the face of its parents and learns to recognise them. We also know that, for some species, this imprinting can be tricked: this is how Konrad Lorenz, the “father of ethology”, became the imprinted parent of newly hatched ducks and geese. Fish are probably no different and can learn to remember people and faces for various benefits. My own archerfish learned to differentiate me from my wife and other guests, because I was the only one who fed them. So, I think the ability to see yourself isn’t really a prerequisite to recognising your own species. Given the importance of staying in schools for some species of fish, I suspect they use a variety of inputs, including visual and olfactory, plus learned experiences of safety versus danger. Then there’s innate recognition, which must play a role in some species of fish that are so sparsely distributed that, when a male meets a mate, they attach to them and never let go, for example deep-sea anglerfishes.
Tom Gauld for New Scientist
I doubt a male deep-sea anglerfish in this situation has ever seen itself or even another individual of its species before, but it still seems to know to attach itself to a female. In this case, it is almost certainly down to an olfactory cue, but there will be many other interesting and bizarre examples in the world of fish.
Head banging
When wasps, bees and flies continually clatter against the glass of my conservatory attempting a means of escape, are they following a strategy? (continued)
Alan Harding
London, UK
I think the previous answer
to this question misses an
important difference between
flies, wasps and bees (4 July).
In my experience, wasps and
bees continually buzz around
in more or less the same part of
a window and are very easy to
catch – for example by trapping
“ Moving towards light has served flies well, but when confronted by glass – a relatively recent innovation – it can be fatally futile”
them under an upturned
glass, covering it with a piece
of paper and releasing them
through an open window.
With flies, on the other hand,
this is almost impossible, as they
tend to buzz around randomly.
I don’t think this is a strategy
for escaping (as was previously
said, they have no concept of
glass), but rather a strategy
for not being eaten.
Bees and wasps have stings and
stripy bodies to warn predators
‘“eat me at your peril”. I think flies’
random flight paths have evolved
to make it much harder for
predators to catch and eat them.
Jonathan Wallace Newcastle-upon-Tyne, UK It was suggested by your previous correspondent that flies and bees
banging against the window
to escape from a room aren’t
following any specific strategy.
This is probably incorrect.
If you observe a fly as it moves
around a room, you won’t see it
repeatedly flying against the wall
in the way that it does against the
glass of a window. This suggests
that the fly (or bee) clearly “sees”
the window as the way out.
Flying insects don’t reason
their way out of the room in the
way that we would, but are likely
to have evolved a strategy of
instinctively flying towards the
light when inside a dark space.
In most circumstances, this
simple strategy works well for
them, but when confronted by
glass – a very recent innovation
in the evolutionary history of
flies – the strategy becomes
potentially fatally futile.
Garry Trethewey Arkaroola, South Australia Yes. The strategy is “head towards the light”. That has worked for them for millions of years, sans windows. Now, it doesn’t. ❚
Answers
DOWN 1 Stigma, 2 Once, 3 Warfarin, 4 Photon, 5 Horizontal, 6 Reaction, 8 Disappearance, 13 Delphinine, 15 Bearings, 16 Inflated, 18 Typist, 20 Nitric, 22 Gate
ACROSS 7 Standard, 9 Hooker, 10 Ogee, 11 Fast-twitch, 12 Sander, 14 Pangolin, 15 Balance piston, 17 Catheter, 19 Feline, 21 Giant panda, 22 Go to, 23 Agents, 24 Electric
Quick crossword
5 Erwin Schrödinger
4 Hadean
3 Flores
2 Peter Shor
1 Histamine
Quick quiz #362
Block Universe
Solution
Stony ground
When you start watching a film, there are some characters you can confidently predict will die. A minor character joining two major characters for an action sequence? Dead to illustrate the stakes. Wise old mentor in an epic fantasy? Sure to die at the end of act two. Feedback knows these cliches and more, but it hadn’t previously occurred to us to consider geologists as being at risk. Nevertheless, it turns out they have a life expectancy only marginally better than characters played by Sean Bean. We learned this from a delightful analysis in Geology Today. Geologist Erik Sturkell at the University of Gothenburg in Sweden and his colleagues have amused themselves over the past decade or so by compiling examples of geologists in films: who are they, how are they portrayed and what tends to happen to them? Sturkell’s team has now documented “141 movies, spanning the period 1919–2023 and starring 202 geologists”. It turns out geologists mostly appear in films centred on adventure, drama, action and science fiction. “Geologist movies are rarely comedic,” write the researchers. Only 11 per cent of movie geologists are female, though this has apparently picked up a bit since the 1990s. Furthermore, cinematic geologists are, if not consistently heroic, “at least not guilty of any professional misconduct”. And yet they are frequently rubbed out. “Geologists die at an alarming rate in the movies, often very early on,” the authors write. Depending on the decade, the death rate varies between 31.6 and 35.7 per cent. Of the 202 geologists, 69 die, 30 by murder. The authors cite the 1967 film The Money Jungle, which Feedback hasn’t seen, but which involves multiple oil companies scheming for control of a rich field. During this unseemly squabble, five geologists are murdered, mostly by creative means, “such as being electrocuted by a golf cart, poisoned when taking
Twisteddoodles for New Scientist
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Send it to feedback@newscientist.com
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Consideration of items sent in the post will be delayed
medicine, gassed by the fireplace and killed when his toy train explodes”. This, the authors note, is “the worst serial slaughter of geologists in any movie”. Across the years, a further 12 geologists died of “work related” causes, such as “being hit by a volcanic bomb, falling into a crater or an opening fault, drowning in quicksand or lahar, and incineration in an oil pit”. Equally common are deaths involving extraterrestrials, such as the geologist in Prometheus who is assimilated by aliens and “consequently killed by former colleagues”. This is all fascinating, but Feedback finds ourselves consumed by follow-up questions. What are the cinematic death rates for other branches of science? We can’t help but suspect that palaeontologists must be absolutely getting it in the neck, because they only show up
in stories where extinct creatures come back to life and start eating people. On the other hand, movie solid-state physicists are probably having a pretty chill time. Can anyone point us to a dataset?
Me, me, me
Feedback is alarmed to learn that the lyrics of pop music have become significantly more self- centred over the past few decades. This is true in the US and Germany, according to a study in PLoS One, which looked at the 10 most popular songs each year from 1970 to 2019. The analysis revealed an increase in the use of first-person singular words like “I”, “me” and “mine”, compared with first-person plural words like “we” and “ours”. Curiously, this didn’t occur in Japan and Hong Kong, which the study
describes as “more collectivist”. The paper treats this in near-apocalyptic terms, noting that “contemporary societies are increasingly self-focused, as reflected in levels of greed, narcissism, and social disconnection”. Feedback certainly isn’t going to mount a “greed is good” defence, but we do have questions. For starters, how much of the trend is driven by the highly entrepreneurial US, as opposed to the more moderately capitalistic Germany? Second, how much of the increase in “me” words can be explained by the rise of solo artists and the total collapse of bands? Do K-pop groups – at this point basically the only remaining successful bands – also exhibit this egotistical trend?
She’ll be back
Last month, New Scientist reviewed the book We Are Not Machines: The fight for the future of work, which argues that artificial intelligence is not exactly coming for our jobs, but rather that our jobs are being contorted to fit AI (20 June, p 24). The result is that jobs that were once interesting are becoming boring and companies’ products and services are getting worse. Readers Ian Williams and Erik Foxcroft both got in touch to flag the spooky near-coincidence that the book’s author, a journalist at the Financial Times, is named Sarah O’Connor. “O, how close to perfection,” says Erik. Having a name that is almost but not quite that of the lead human character in The Terminator has previously caused ripples. In 2015, O’Connor was the FT’s employment correspondent and tweeted: “A robot has killed a worker in a VW plant in Germany.” The combination of seeming cyborg-murderer news and O’Connor’s name went viral. The irony was that she had never seen the film and didn’t get the reference. Feedback assumes she has since watched it, and hopes she concluded her book with a three-word promise of a sequel. ❚
Stone Age, Archaeology Maya, Assia Arouf, Association International Conference, Astor Place, At Iceland, Australia We, Australia You, Biophysics Reviews, Block Universe Solution
Page
审计结论：存在严重交付缺陷 (Blocking Issues Found)
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