Recently NASA Headquarters made the following announcement:
NASA’s Asteroid Bennu Sample Reveals Mix of Life’s
Ingredients (2/2)
Jessica Taveau
Jan 29, 2025
NASA Headquarters
(continue)
While Glavin’s team analyzed the Bennu samples for hints of
life-related compounds, their colleagues, led by Tim McCoy, curator of
meteorites at the Smithsonian’s National Museum of Natural History in
Washington, and Sara Russell, cosmic mineralogist at the Natural History Museum
in London, looked for clues to the environment these molecules would have
formed. Reporting in the journal Nature, scientists further describe evidence
of an ancient environment well-suited to kickstart the chemistry of life.
Ranging from calcite to halite and sylvite, scientists identified traces of 11 minerals in the Bennu sample that form as water containing dissolved salts evaporates over long periods of time, leaving behind the salts as solid crystals.
Similar brines have been detected or suggested across the solar system, including at the dwarf planet Ceres and Saturn’s moon Enceladus.
Although scientists have previously detected several evaporites in meteorites that fall to Earth’s surface, they have never seen a complete set that preserves an evaporation process that could have lasted thousands of years or more. Some minerals found in Bennu, such as trona, were discovered for the first time in extraterrestrial samples.
“These papers really go hand in hand in trying to explain how life’s ingredients actually came together to make what we see on this aqueously altered asteroid,” said McCoy.
For all the answers the Bennu sample has provided, several questions remain. Many amino acids can be created in two mirror-image versions, like a pair of left and right hands. Life on Earth almost exclusively produces the left-handed variety, but the Bennu samples contain an equal mixture of both. This means that on early Earth, amino acids may have started out in an equal mixture, as well. The reason life “turned left” instead of right remains a mystery.
NASA Goddard provided overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. The university leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provided flight operations. NASA Goddard and KinetX Aerospace were responsible for navigating the OSIRIS-REx spacecraft. Curation for OSIRIS-REx takes place at NASA’s Johnson Space Center in Houston. International partnerships on this mission include the OSIRIS-REx Laser Altimeter instrument from CSA (Canadian Space Agency) and asteroid sample science collaboration with JAXA’s (Japan Aerospace Exploration Agency) Hayabusa2 mission. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, managed by the agency’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
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（2/2）
美國太空總署總部
（繼續）
當 Glavin 的團隊分析貝努樣本以尋找與生命相關的化合物的線索時，他們的同事在華盛頓Smithsonian
國家自然歷史博物館隕石館長 Tim McCoy 和倫敦自然歷史博物館宇宙礦物學家
Sara Russell 的帶領下，尋找這些分子形成環境的線索。在《自然》雜誌的報導中，科學家進一步描述了適合啟動生命化學反應的古老環境的證據。
科學家在貝努樣本中發現了從方解石到岩鹽和鉀鹽等 11 種礦物質的痕跡，這些礦物質是在含有溶解鹽的水經過長時間蒸發後形成的，留下的是固體鹽晶體。
整個太陽係都曾發現或顯示存在類似的鹽水，包括矮行星穀神星和土星的衛星土衛二。
儘管科學家先前曾在墜落地球表面的隕石中發現過幾塊蒸發岩，但他們從未見過一組完整地保存著可能持續數千年甚至更長時間的蒸發過程的蒸發岩。貝努中發現的一些礦物，例如天然鹼，是首次在地外樣本中發現的。
McCoy說： “這些論文確實相連關並同時試圖解釋生命個別成分是如何結合在一起, 並形成我們在這顆被水改變的小行星上看到的生命景象的。”
儘管貝努樣本提供了所有答案，但仍有幾個問題尚待解答。許多氨基酸可以以兩個鏡影版本建造成，就像一雙左手和右手一樣。地球上的生命幾乎只產生左手性種類生命，但貝努樣本同時含有兩種版本生命。這意味著在早期地球上，氨基酸也可能是以均等的混合物的形式出現的。生命「向左轉」而不是向右轉的原因仍然是個謎。
美國宇航局 Goddard 太空飛行中心 OSIRIS-REx 項目科學家、《自然天文學》論文聯合作者
Jason Dworkin 表示：「OSIRIS-REx 是一次非常成功的任務」; 「OSIRIS-REx
的數據為充滿生命潛力的太陽系圖景增添了重要一筆。為什麼到目前為止我們只在地球上看到生命而在其他地方卻看不到，這才是真正誘人的問題」。
美國太空總署 Goddard 為 OSIRIS-REx 提供了整體任務管理、系統工程以及安全和任務保障。亞利桑那大學圖森分校的Dante Lauretta 是首席研究員。該大學領導科學團隊和任務的科學觀測規劃和數據處理。位於科羅拉多州 Littleton 的 Lockheed Martin Space 建造了該太空船並提供飛行操作。美國太空總署Goddard和 KinetX Aerospace 負責導航 OSIRIS-REx 太空船。 OSIRIS-REx 的策展在美國宇航局位於休士頓的約翰遜航天中心進行。這項任務的國際合作夥伴包括加拿大太空總署 (CSA) 的 OSIRIS-REx 雷射高度計儀器, 行星樣本科學是與日本宇宙航空研究開發機構 (JAXA) 的隼鳥 2 號任務合作。 OSIRIS-REx 是美國太空總署新疆界計劃的第三次任務，由位於阿拉巴馬州Huntsville的 馬歇爾太空飛行中心管理, 代表著華盛頓的美國太空總署科學任務理事會。
So, studies of
rock and dust from asteroid Bennu 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.
Note:
1. An evaporite (蒸發岩)is a water-soluble sedimentary
mineral deposit that results from concentration and crystallization by
evaporation from an aqueous solution. There are two types of evaporite
deposits: marine, which can also be described as ocean deposits, and
non-marine, which are found in standing bodies of water such as lakes.
Evaporites are considered sedimentary rocks and are formed by chemical
sediments. (Wikipedia)
2. Trona (天然碱) is a non-marine evaporite
mineral. It is mined as the primary source of sodium carbonate in the United
States, where it has replaced the Solvay process used in most of the rest of
the world for sodium carbonate production. (Wikipedia)
3. The Science Mission Directorate (SMD) (科學任務理事會) of
the National Aeronautics and Space Administration (NASA) engages the United
States' science community, sponsors scientific research, and develops and
deploys satellites and probes in collaboration with NASA's partners around the
world. (Wikipedia)
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