Recently NASA Headquarters made the following announcement:
NASA’s Asteroid Bennu Sample Reveals Mix of Life’s
Ingredients (1/2)
Jessica Taveau
Jan 29, 2025
NASA Headquarters
Studies of rock and dust from asteroid Bennu delivered to
Earth by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification
and Security–Regolith Explorer) spacecraft have revealed molecules that, on our
planet, are key to life, as well as a history of saltwater that could have
served as the “broth” for these compounds to interact and combine.
The findings do not show evidence for life itself, but they do suggest the conditions necessary for the emergence of life were widespread across the early solar system, increasing the odds life could have formed on other planets and moons.
In research papers published Wednesday in the journals Nature and Nature Astronomy, scientists from NASA and other institutions shared results of the first in-depth analyses of the minerals and molecules in the Bennu samples, which OSIRIS-REx delivered to Earth in 2023.
Detailed in the Nature Astronomy paper, among the most compelling detections were amino acids – 14 of the 20 that life on Earth uses to make proteins – and all five nucleobases that life on Earth uses to store and transmit genetic instructions in more complex terrestrial biomolecules, such as DNA and RNA, including how to arrange amino acids into proteins.
Scientists also described exceptionally high abundances of ammonia in the Bennu samples. Ammonia is important to biology because it can react with formaldehyde, which also was detected in the samples, to form complex molecules, such as amino acids – given the right conditions. When amino acids link up into long chains, they make proteins, which go on to power nearly every biological function.
These building blocks for life detected in the Bennu samples have been found before in extraterrestrial rocks. However, identifying them in a pristine sample collected in space supports the idea that objects that formed far from the Sun could have been an important source of the raw precursor ingredients for life throughout the solar system.
“The clues we’re looking for are so minuscule and so easily destroyed or altered from exposure to Earth’s environment,” said Danny Glavin, a senior sample scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and co-lead author of the Nature Astronomy paper. “That’s why some of these new discoveries would not be possible without a sample-return mission, meticulous contamination-control measures, and careful curation and storage of this precious material from Bennu.”
(to be continued)
Translation
美國太空總署的小行星貝努樣本揭示了生命成分的混合（1/2）
美國太空總署總部
美國國家航空暨太空總署 (NASA) 的
OSIRIS-REx（即起源、光譜解釋、資源識別和安全 - 風化層探測器的缩寫）太空船將小行星貝努
(Bennu) 的岩石和塵埃帶回地球，對其進行了研究，揭露了它有地球上關乎生命的主要分子，及可能作為這些化合物相互反應和結合的「培養液」的鹽水的歷史。
這些發現並沒有顯示出生命本身存在的證據，但它們確實表明生命出現所必需的條件在早期太陽系中廣泛存在，這增加了生命在其他行星和衛星上形成的可能性。
美國宇航局華盛頓總部科學任務理事會副局長 Nicky Fox 表示： “美國宇航局的 OSIRIS-REx 任務已經改寫了我們對太陽繫起源的認識”; “小行星為我們了解地球的歷史提供了一個時間囊，而貝努的樣本對於我們去了解地球生命開始之前太陽系中存在哪些成分至關重要。”
在周三發表在《自然》和《自然天文學》雜誌上的研究論文中，美國宇航局和其他機構的科學家分享了對貝努樣本中礦物質和分子的首次深入分析結果，OSIRIS-REx 是於 2023 年將這些樣本帶回地球。
《自然天文學》論文詳細介紹了最令人信服的發現，包括氨基酸 - 地球生命用來製造蛋白質的20種氨基酸中的14種，以及地球生命用來在更複雜的陸地生物分子（如DNA和RNA）中存儲和傳輸遺傳指令的所有五種核鹼基，包括如何將氨基酸排列成蛋白質。
科學家也描述了貝努樣本中異常高含量的氨。氨對生物學很重要，因為它可以與樣本中檢測到的甲醛反作出化學應，在適合的條件下形成複雜的分子，例如胺基酸。當胺基酸連接成長鏈時，它們就會形成蛋白質，進而為幾乎所有的生物功能提供動力。
在貝努樣本中檢測到的這些生命構成要素, 以前也曾在外星岩石中發現過。然而，在太空中收集的原始樣本中能發現它們, 支持了這樣一種觀點：即遠離太陽形成的物體, 可能是整個太陽系原始生命的前驅的重要來源。
美國宇航局馬裡蘭州 Greenbelt 的 Goddard 太空飛行中心的高級樣本科學家、亦是《自然天文學》論文的共同主要作者 Danny Glavin 說: 「我們正在尋找的線索非常微小，而且很容易因暴露在地球環境中而被破壞或改變」; 「這就是為什麼如果沒有把樣品送回的任務、沒有細緻的污染控制措施, 以及對來自貝努的珍貴材料的精心管理和儲存，這些新發現就不可能實現」。
（待續）
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