編譯|馮維維
Nature, 4 September 2025, Volume 645 Issue 8079
《自然》2025年9月4日，645卷，8079期
物理學Physics
Seismic detection of a 600-km solid inner core in Mars
火星600公里固態內核的地震學探測
▲ 作者：Huixing Bi, Daoyuan Sun, Ningyu Sun, Zhu Mao, Mingwei Dai & Douglas Hemingway
▲鏈接：
https://www.nature.com/articles/s41586-025-09361-9
▲摘要：
中國科學技術大學孫道遠等利用美國國家航空航天局（NASA）“洞察”號（InSight），發現了火星存在固態內核的證據。該發現有助于進一步理解了火星和類似行星天體的性質和演化。已知火星內核至少為部分液態，而理論研究認為火星內核可能有固態的成分。不過，此前研究一直無法確認火星核是否存在固態成分。孫道遠和同事利用NASA“洞察”號任務采集的地震數據研究火星內核的結構。測量數據顯示存在兩個地震震相：PKKP，一個穿過內核的深部震相；PKiKP，這是提示存在固態內核的一個反射震相（此前經地球和月球證實）。PKKP震相的地震波抵達洞察號著陸器上地震儀的時間比假設內核為純液態的時間提早了50-200秒，說明內核結構存在固態元素。根據對這些數據的進一步計算，作者將內核半徑限定在600千米左右。該發現為火星有固態內核提供了直接證據，并帶來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
面向全頻譜無線通信的超寬帶芯片光子技術
▲ 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
▲鏈接：
https://www.nature.com/articles/s41586-025-09451-8
▲摘要：
即將到來的第六代未來無線網絡需在從微波、毫米波到太赫茲波段的廣闊頻率范圍內運行，以支持多樣化應用場景的泛在連接。這要求硬件解決方案具備“一體適用”特性，能夠在此寬頻譜內自適應重構，實現全波段覆蓋與動態頻譜管理。然而，現有電學或光子輔助解決方案因器件帶寬限制和系統架構固有剛性，難以滿足此需求。
研究者演示了基于薄膜鈮酸鋰（TFLN）光子無線系統的突破性成果——在超過100吉赫茲的頻率范圍內實現自適應無線通信。通過利用普克爾斯效應和TFLN平臺的可擴展性，他們實現了關鍵功能單元的單片集成，包括基帶調制、寬帶無線-光子轉換以及可重構載波與本地信號生成。借助寬帶可調光電振蕩器，信號源可在0.5吉赫茲至115吉赫茲的創紀錄寬頻范圍內工作，且具備高頻率穩定性和一致相干性。基于這種寬帶可重構集成光子解決方案，研究者實現了連續九個波段的全鏈路無線通信，單通道速率高達100 Gbps。實時重配置能力進一步支持自適應頻率分配，這是確保復雜頻譜環境中增強可靠性的關鍵能力。本研究標志著向未來全頻譜全場景無線網絡邁出的重要一步。
▲ 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
通過電子衍射實驗測定原子部分電荷
▲ 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
▲鏈接：
https://www.nature.com/articles/s41586-025-09405-0
▲ 摘要：
原子部分電荷作為理解分子結構、相互作用及反應性的核心參數，至今仍是一個缺乏精確量子力學定義的模糊概念。準確測定原子部分電荷對化學合成、材料應用科學和理論化學等領域具有深遠影響。其在分子動力學模擬中起著至關重要的作用，這種模擬可充當化學過程的“計算顯微鏡”。迄今為止，尚未有通用實驗方法能夠量化化合物中單個原子的部分電荷。
研究者介紹了一種基于電子衍射晶體結構測定的實驗方法，可適用于任何晶體化合物。該方法可無縫集成至標準電子晶體學工作流程，無需專用軟件或高級專業知識，且不受化合物類別限制。通過對多種化合物的應用驗證了該方法的普適性，包括抗生素環丙沙星、氨基酸組氨酸與酪氨酸，以及無機沸石ZSM-5。研究者將這一新概念稱為"離子散射因子建模"。該方法促進了對分子結構更全面精確的理解，為化學與材料科學眾多領域的應用提供了新機遇。
▲ 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
手性光電離動力學的阿秒控制與測量
▲ 作者：Meng Han, Jia-Bao Ji, Alexander Blech, R. Esteban Goetz, Corbin Allison, Loren Greenman, Christiane P. Koch & Hans Jakob W?rner
▲鏈接：
https://www.nature.com/articles/s41586-025-09455-4
▲ 摘要：
許多手性敏感的光—物質相互作用受手性電子動力學支配。因此，利用手性現象的先進技術的發展，亟需在其天然的阿秒時間尺度上實現對手性電子動力學的測量與控制。這一努力長期以來受限于缺乏特征明確的圓偏振阿秒脈沖，而該障礙近期已被突破。
研究者介紹了阿秒脈沖圓偏振光譜技術，實現了對光電子圓二色性（PECD）的阿秒相干控制，并測量了手性分子前向—后向及角度分辨光電離延遲的手性不對稱性。研究發現：與單光子電離相比，同向旋轉的阿秒脈沖與近紅外（IR）脈沖聯合作用可使PECD效應增強近一倍，甚至改變其符號。
研究證實手性光電離延遲同時取決于光傳播坐標系中光發射的極角和方位角，需要三維動量分辨率進行測量。實驗測得前向—后向手性敏感延遲可達60阿秒，極角分辨光電離延遲達240阿秒，其中包含源于連續—連續躍遷手性的約60阿秒不對稱性。阿秒圓偏振光譜技術為在電子時間尺度上定量理解與控制手性分子動力學開啟了新紀元。
▲ 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.
行星化學Planetary Chemistry
Mapping urban gullies in the Democratic Republic of the Congo
低溫低金屬豐度褐矮星中硅酸鹽前驅體硅烷的檢測
▲ 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
▲鏈接：
https://www.nature.com/articles/s41586-025-09369-1
▲ 摘要：
在太陽系20秒差距范圍內，目前已知存在29顆冷褐矮星——這些天體不僅已測量距離，且有效溫度介于木星（170K）至約500K之間。它們幾乎均處于孤立狀態，成為研究太陽系外形成的氣態巨行星大氣特性的最近實驗室。
研究者報道了利用詹姆斯·韋伯空間望遠鏡（JWST）對WISEA J153429.75-104303.3（簡稱W1534）的觀測結果，確認該天體是銀河系暈中的亞恒星質量成員，金屬豐度不足太陽值的百分之一。其光譜揭示了甲烷、水和硅烷氣體的存在。雖然硅烷被認為是氣態巨行星中云層形成元素硅的關鍵儲庫，但此前始終未被探測到——因其在深層大氣中會通過硅酸鹽云的形成而被消耗。這種凝結過程隨金屬豐度增加而增強，這解釋了為何在木星和土星等已充分研究的富金屬太陽系天體上未能檢測到硅烷。
在貧金屬天體W1534上，研究者在4.55微米附近清晰檢測到硅烷特征信號，其豐度為19±2 ppb（十億分之一）。化學模型表明，該硅烷豐度可能是在硅酸鹽云層上方約千巴壓力高度處被“淬滅”固定，此處的大氣垂直混合作用可將硅烷輸送至可觀測的光球層。硅烷的形成與檢測證實了冷褐矮星和行星大氣中成分、云層形成與大氣混合三者之間存在關鍵耦合關系。
▲ 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.
生態學Ecology
Global phenology maps reveal the drivers and effects of seasonal asynchrony
全球物候圖譜揭示季節性異步性的驅動因素與生態效應
▲ 作者：Drew E. Terasaki Hart, Th?o-Nguyên Bùi, Lauren Di Maggio & Ian J. Wang
▲鏈接：
https://www.nature.com/articles/s41586-025-09410-3
▲ 摘要：
陸地植物群落每年呈現差異顯著的年生長節律，即季節性物候。由此產生的空間格局被稱為地表物候，蘊含研究生態系統功能、植物生態生理學、景觀生態學及進化生物地理學的重要信息。然而，現有方法難以準確表征陸地生物群系中各種季節性物候，特別是許多干旱區和熱帶生態系統微妙而復雜的物候模式，導致全球一致性LSP制圖始終面臨挑戰。
研究通過衛星影像的數據驅動分析實現全球LSP制圖，揭示了地球物候多樣性：既記錄了相似氣候條件下的跨大陸趨同現象，也發現了與地形氣候、生態水文學和植被結構相關的區域異質性。進而繪制空間物候異步性及其控制模式圖，確定熱帶山地和地中海氣候區為異步性熱點區域，并為"熱帶內氣候相似站點具有更高物候異步性"的假說提供證據。
研究者發現，全球LSP圖譜能預測多種分類群在開花物候、遺傳分化乃至收獲季節性方面的復雜地理間斷性，由此認為遙感技術可作為理解異域分布引起物候異步性之生態與進化后果的關鍵工具。
▲ 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.
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