编译|冯维维

Nature, 4 September 2025, Volume 645 Issue 8079

《自然》2025年9月4日，645卷，8079期

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物理学Physics

Seismic detection of a 600-km solid inner core in Mars

火星600公里固态内核的地震学探测

▲ 作者：Huixing Bi, Daoyuan Sun, Ningyu Sun, Zhu Mao, Mingwei Dai & Douglas Hemingway

▲链接：

https://www.nature.com/articles/s41586-025-09361-9

▲摘要：

中国科学技术大学孙道远等利用美国国家航空航天局（NASA）“洞察”号（InSight），发现了火星存在固态内核的证据。该发现有助于进一步理解了火星和类似行星天体的性质和演化。已知火星内核至少为部分液态，而理论研究认为火星内核可能有固态的成分。不过，此前研究一直无法确认火星核是否存在固态成分。孙道远和同事利用NASA“洞察”号任务采集的地震数据研究火星内核的结构。测量数据显示存在两个地震震相：PKKP，一个穿过内核的深部震相；PKiKP，这是提示存在固态内核的一个反射震相（此前经地球和月球证实）。PKKP震相的地震波抵达洞察号着陆器上地震仪的时间比假设内核为纯液态的时间提早了50-200秒，说明内核结构存在固态元素。根据对这些数据的进一步计算，作者将内核半径限定在600千米左右。该发现为火星有固态内核提供了直接证据，并带来了火星演化的新信息。

▲ Abstract：

For rocky planets, the presence of a solid inner core has notable implications on the composition and thermal evolution of the core and on the magnetic history of the planet. On Mars, geophysical observations have confirmed that the core is at least partially liquid, but it is unknown whether any part of the core is solid. Here we present an analysis of seismic data acquired by the InSight mission, demonstrating that Mars has a solid inner core. We identify two seismic phases, the deep core-transiting phase, PKKP, and the inner core boundary reflecting phase, PKiKP, indicative of the inner core. Our inversions constrain the radius of the Martian inner core to about 613 ± 67 km, with a compressional velocity jump of around 30% across the inner core boundary, supported by additional inner-core-related seismic phases. These properties imply a concentration of distinct light elements in the inner core, segregated from the outer core through core crystallization. This finding provides an anchor point for understanding the thermal and chemical state of Mars. Moreover, the relationship between inner core formation and the Martian magnetic field evolution could provide insights into dynamo generation across planetary bodies.

Ultrabroadband on-chip photonics for full-spectrum wireless communications

面向全频谱无线通信的超宽带芯片光子技术

▲ 作者：Zihan Tao, Haoyu Wang, Hanke Feng, Yijun Guo, Bitao Shen, Dan Sun, Yuansheng Tao, Changhao Han, Yandong He, John E. Bowers, Haowen Shu, Cheng Wang & Xingjun Wang

▲链接：

https://www.nature.com/articles/s41586-025-09451-8

▲摘要：

即将到来的第六代未来无线网络需在从微波、毫米波到太赫兹波段的广阔频率范围内运行，以支持多样化应用场景的泛在连接。这要求硬件解决方案具备“一体适用”特性，能够在此宽频谱内自适应重构，实现全波段覆盖与动态频谱管理。然而，现有电学或光子辅助解决方案因器件带宽限制和系统架构固有刚性，难以满足此需求。

研究者演示了基于薄膜铌酸锂（TFLN）光子无线系统的突破性成果——在超过100吉赫兹的频率范围内实现自适应无线通信。通过利用普克尔斯效应和TFLN平台的可扩展性，他们实现了关键功能单元的单片集成，包括基带调制、宽带无线-光子转换以及可重构载波与本地信号生成。借助宽带可调光电振荡器，信号源可在0.5吉赫兹至115吉赫兹的创纪录宽频范围内工作，且具备高频率稳定性和一致相干性。基于这种宽带可重构集成光子解决方案，研究者实现了连续九个波段的全链路无线通信，单通道速率高达100 Gbps。实时重配置能力进一步支持自适应频率分配，这是确保复杂频谱环境中增强可靠性的关键能力。本研究标志着向未来全频谱全场景无线网络迈出的重要一步。

▲ Abstract：

The forthcoming sixth-generation and beyond wireless networks are poised to operate across an expansive frequency range—from microwave, millimetre wave to terahertz bands—to support ubiquitous connectivity in diverse application scenarios. This necessitates a one-size-fits-all hardware solution that can be adaptively reconfigured within this wide spectrum to support full-band coverage and dynamic spectrum management. However, existing electrical or photonic-assisted solutions face a lot of challenges in meeting this demand because of the limited bandwidths of the devices and the intrinsically rigid nature of system architectures. Here we demonstrate adaptive wireless communications over an unprecedented frequency range spanning over 100 GHz, driven by a thin-film lithium niobate (TFLN) photonic wireless system. Leveraging the Pockels effect and scalability of the TFLN platform, we achieve monolithic integration of essential functional elements, including baseband modulation, broadband wireless–photonic conversion and reconfigurable carrier and local signal generation. Powered by broadband tunable optoelectronic oscillators, our signal sources operate across a record-wide frequency range from 0.5 GHz to 115 GHz with high-frequency stability and consistent coherence. Based on the broadband and reconfigurable integrated photonic solution, we realize full-link wireless communication across nine consecutive bands, achieving record lane speeds of up to 100 Gbps. The real-time reconfigurability further enables adaptive frequency allocation, a crucial ability to ensure enhanced reliability in complex spectrum environments. Our proposed system represents a marked step towards future full-spectrum and omni-scenario wireless networks.

Experimental determination of partial charges with electron diffraction

通过电子衍射实验测定原子部分电荷

▲ 作者：Soheil Mahmoudi, Tim Gruene, Christian Schr?der, Khalil D. Ferjaoui, Erik Fr?jdh, Aldo Mozzanica, Kiyofumi Takaba, Anatoliy Volkov, Julian Maisriml, Vladimir Paunovi?, Jeroen A. van Bokhoven & Bernhard K. Keppler

▲链接：

https://www.nature.com/articles/s41586-025-09405-0

▲ 摘要：

原子部分电荷作为理解分子结构、相互作用及反应性的核心参数，至今仍是一个缺乏精确量子力学定义的模糊概念。准确测定原子部分电荷对化学合成、材料应用科学和理论化学等领域具有深远影响。其在分子动力学模拟中起着至关重要的作用，这种模拟可充当化学过程的“计算显微镜”。迄今为止，尚未有通用实验方法能够量化化合物中单个原子的部分电荷。

研究者介绍了一种基于电子衍射晶体结构测定的实验方法，可适用于任何晶体化合物。该方法可无缝集成至标准电子晶体学工作流程，无需专用软件或高级专业知识，且不受化合物类别限制。通过对多种化合物的应用验证了该方法的普适性，包括抗生素环丙沙星、氨基酸组氨酸与酪氨酸，以及无机沸石ZSM-5。研究者将这一新概念称为"离子散射因子建模"。该方法促进了对分子结构更全面精确的理解，为化学与材料科学众多领域的应用提供了新机遇。

▲ Abstract：

Atomic partial charges, integral to understanding molecular structure, interactions and reactivity, remain an ambiguous concept lacking a precise quantum-mechanical definition. The accurate determination of atomic partial charges has far-reaching implications in fields such as chemical synthesis, applied materials science and theoretical chemistry, to name a few. They play essential parts in molecular dynamics simulations, which can act as a computational microscope for chemical processes. Until now, no general experimental method has quantified the partial charges of individual atoms in a chemical compound. Here we introduce an experimental method that assigns partial charges based on crystal structure determination through electron diffraction, applicable to any crystalline compound. Seamlessly integrated into standard electron crystallography workflows, this approach requires no specialized software or advanced expertise. Furthermore, it is not limited to specific classes of compounds. The versatility of this method is demonstrated by its application to a wide array of compounds, including the antibiotic ciprofloxacin, the amino acids histidine and tyrosine, and the inorganic zeolite ZSM-5. We refer to this new concept as ionic scattering factors modelling. It fosters a more comprehensive and precise understanding of molecular structures, providing opportunities for applications across numerous fields in the chemical and materials sciences.

Attosecond control and measurement of chiral photoionization dynamics

手性光电离动力学的阿秒控制与测量

▲ 作者：Meng Han, Jia-Bao Ji, Alexander Blech, R. Esteban Goetz, Corbin Allison, Loren Greenman, Christiane P. Koch & Hans Jakob W?rner

▲链接：

https://www.nature.com/articles/s41586-025-09455-4

▲ 摘要：

许多手性敏感的光—物质相互作用受手性电子动力学支配。因此，利用手性现象的先进技术的发展，亟需在其天然的阿秒时间尺度上实现对手性电子动力学的测量与控制。这一努力长期以来受限于缺乏特征明确的圆偏振阿秒脉冲，而该障碍近期已被突破。

研究者介绍了阿秒脉冲圆偏振光谱技术，实现了对光电子圆二色性（PECD）的阿秒相干控制，并测量了手性分子前向—后向及角度分辨光电离延迟的手性不对称性。研究发现：与单光子电离相比，同向旋转的阿秒脉冲与近红外（IR）脉冲联合作用可使PECD效应增强近一倍，甚至改变其符号。

研究证实手性光电离延迟同时取决于光传播坐标系中光发射的极角和方位角，需要三维动量分辨率进行测量。实验测得前向—后向手性敏感延迟可达60阿秒，极角分辨光电离延迟达240阿秒，其中包含源于连续—连续跃迁手性的约60阿秒不对称性。阿秒圆偏振光谱技术为在电子时间尺度上定量理解与控制手性分子动力学开启了新纪元。

▲ Abstract：

Many chirality-sensitive light–matter interactions are governed by chiral electron dynamics. Therefore, the development of advanced technologies making use of chiral phenomena would critically benefit from measuring and controlling chiral electron dynamics on their natural attosecond timescales. Such endeavours have so far been hampered by the lack of characterized circularly polarized attosecond pulses, an obstacle that has recently been overcome. Here we introduce chiroptical spectroscopy with attosecond pulses and demonstrate attosecond coherent control over photoelectron circular dichroism (PECD), as well as the measurement of chiral asymmetries in the forward–backward and angle-resolved photoionization delays of chiral molecules. We show that co-rotating attosecond and near-infrared (IR) pulses can nearly double the PECD and even change its sign compared with single-photon ionization. We demonstrate that chiral photoionization delays depend on both polar and azimuthal angles of photoemission in the light-propagation frame, requiring 3D momentum resolution. We measure forward–backward chiral-sensitive delays of up to 60 as and polar-angle-resolved photoionization delays of up to 240 as, which include an asymmetry of about 60 as originating from chirality in the continuum–continuum transitions. Attosecond chiroptical spectroscopy opens the door to quantitatively understanding and controlling the dynamics of chiral molecules on the electronic timescale.

行星化学Planetary Chemistry

Mapping urban gullies in the Democratic Republic of the Congo

低温低金属丰度褐矮星中硅酸盐前驱体硅烷的检测

▲ 作者：Jacqueline K. Faherty, Aaron M. Meisner, Ben Burningham, Channon Visscher, Michael Line, Genaro Suárez, Jonathan Gagné, Sherelyn Alejandro Merchan, Austin James Rothermich, Adam J. Burgasser, Adam C. Schneider, Dan Caselden, J. Davy Kirkpatrick, Marc Jason Kuchner, Daniella Carolina Bardalez Gagliuffi, Peter Eisenhardt, Christopher R. Gelino, Eileen C. Gonzales, Federico Marocco, Sandy Leggett, Nicolas Lodieu, Sarah L. Casewell, Pascal Tremblin, Michael Cushing, Eduardo L. Martin

▲链接：

https://www.nature.com/articles/s41586-025-09369-1

▲ 摘要：

在太阳系20秒差距范围内，目前已知存在29颗冷褐矮星——这些天体不仅已测量距离，且有效温度介于木星（170K）至约500K之间。它们几乎均处于孤立状态，成为研究太阳系外形成的气态巨行星大气特性的最近实验室。

研究者报道了利用詹姆斯·韦伯空间望远镜（JWST）对WISEA J153429.75-104303.3（简称W1534）的观测结果，确认该天体是银河系晕中的亚恒星质量成员，金属丰度不足太阳值的百分之一。其光谱揭示了甲烷、水和硅烷气体的存在。虽然硅烷被认为是气态巨行星中云层形成元素硅的关键储库，但此前始终未被探测到——因其在深层大气中会通过硅酸盐云的形成而被消耗。这种凝结过程随金属丰度增加而增强，这解释了为何在木星和土星等已充分研究的富金属太阳系天体上未能检测到硅烷。

在贫金属天体W1534上，研究者在4.55微米附近清晰检测到硅烷特征信号，其丰度为19±2 ppb（十亿分之一）。化学模型表明，该硅烷丰度可能是在硅酸盐云层上方约千巴压力高度处被“淬灭”固定，此处的大气垂直混合作用可将硅烷输送至可观测的光球层。硅烷的形成与检测证实了冷褐矮星和行星大气中成分、云层形成与大气混合三者之间存在关键耦合关系。

▲ Abstract：

Within 20 pc of the Sun, there are currently 29 known cold brown dwarfs—sources with measured distances and an estimated effective temperature between that of Jupiter (170 K) and approximately 500 K. These sources are almost all isolated and are the closest laboratories we have for detailed atmospheric studies of giant planets formed outside the Solar System. Here we report JWST observations of one such source, WISEA J153429.75-104303.3 (W1534), which we confirm is a substellar mass member of the Galactic halo with a metallicity of less than 0.01 times solar. Its spectrum reveals methane (CH₄), water (H₂O) and silane (SiH₄) gas. Although SiH₄ is expected to serve as a key reservoir for the cloud-forming element Si in gas giant worlds, it has remained undetected until now because it is removed from observable atmospheres by the formation of silicate clouds at depth. These condensates are favoured with increasing metallicity, explaining why SiH4 remains undetected on well-studied metal-rich Solar System worlds such as Jupiter and Saturn. On the metal-poor world W1534, we detect a clear signature of SiH₄ centred at about 4.55 μm with an abundance of 19 ± 2 parts per billion. Our chemical modelling suggests that this SiH₄ abundance may be quenched at approximately kilobar levels just above the silicate cloud layers, in which vertical atmospheric mixing can transport SiH₄ to the observable photosphere. The formation and detection of SiH₄ demonstrates key coupled relationships between composition, cloud formation and atmospheric mixing in cold brown dwarf and planetary atmospheres.

生态学Ecology

Global phenology maps reveal the drivers and effects of seasonal asynchrony

全球物候图谱揭示季节性异步性的驱动因素与生态效应

▲ 作者：Drew E. Terasaki Hart, Th?o-Nguyên Bùi, Lauren Di Maggio & Ian J. Wang

▲链接：

https://www.nature.com/articles/s41586-025-09410-3

▲ 摘要：

陆地植物群落每年呈现差异显著的年生长节律，即季节性物候。由此产生的空间格局被称为地表物候，蕴含研究生态系统功能、植物生态生理学、景观生态学及进化生物地理学的重要信息。然而，现有方法难以准确表征陆地生物群系中各种季节性物候，特别是许多干旱区和热带生态系统微妙而复杂的物候模式，导致全球一致性LSP制图始终面临挑战。

研究通过卫星影像的数据驱动分析实现全球LSP制图，揭示了地球物候多样性：既记录了相似气候条件下的跨大陆趋同现象，也发现了与地形气候、生态水文学和植被结构相关的区域异质性。进而绘制空间物候异步性及其控制模式图，确定热带山地和地中海气候区为异步性热点区域，并为"热带内气候相似站点具有更高物候异步性"的假说提供证据。

研究者发现，全球LSP图谱能预测多种分类群在开花物候、遗传分化乃至收获季节性方面的复杂地理间断性，由此认为遥感技术可作为理解异域分布引起物候异步性之生态与进化后果的关键工具。

▲ Abstract：

Terrestrial plant communities show great variation in their annual rhythms of growth, or seasonal phenology. The geographical patterns resulting from this variation, known as land surface phenology (LSP), contain valuable information for the study of ecosystem function, plant ecophysiology, landscape ecology and evolutionary biogeography. Yet globally consistent LSP mapping has been hampered by methods that struggle to represent the full range of seasonal phenologies occurring across terrestrial biomes, especially the subtle and complex phenologies of many arid and tropical ecosystems. Here, using a data-driven analysis of satellite imagery to map LSP worldwide, we provide insights into Earth’s phenological diversity, documenting both intercontinental convergence between similar climates and regional heterogeneity associated with topoclimate, ecohydrology and vegetation structure. We then map spatial phenological asynchrony and the modes of asynchronous seasonality that control it, identifying hotspots of asynchrony in tropical mountains and Mediterranean climate regions and reporting evidence for the hypothesis that climatically similar sites exhibit greater phenological asynchrony within the tropics. Finally, we find that our global LSP map predicts complex geographical discontinuities in flowering phenology, genetic divergence and even harvest seasonality across a range of taxa, establishing remote sensing as a crucial tool for understanding the ecological and evolutionary consequences of allochrony by allopatry.