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Deep in a remote, hot, dry patch of northwestern Australia lies one of the earliest detectable signs of life on the planet, tracing back nearly 3.5 billion years, scientists say. |
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在澳洲西北部一個炎熱乾燥的偏遠地區深處，存在著地球上偵測得到最早的生命徵象，時間可追溯到將近三十五億年前，科學家表示。 |
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At that time, the Earth -- relatively speaking -- wasn't into its adulthood yet. |
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Scientists estimate the planet formed roughly 4.5 billion years ago; minerals known as zircons -- indicating water -- and continents existed within 100 million and 200 million years after that on what was still a scalding planet. |
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那時候的地球──相對而言──還沒進入成年期。科學家估計地球大約於四十五億年前形成；鋯石這種礦物──顯示水存在──與大陸在地球形成之後的一億至兩億年間就已存在，當時的地球還是一顆灼熱的行星。 |
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The existence of water suggests that life was possible. |
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But what did it look like, and when did it start? |
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有水存在，就表示可能有生物存在。可是當時的生物看起來是什麼模樣，最早又是出現於什麼時候呢？ |
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The discovery from the Dresser Formation, a much examined outcrop of rocks in Western Australia's Pilbara region, documented in a paper published online this week in the Astrobiology journal may help answer those questions. |
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在德雷瑟層──這是西澳皮爾巴拉地區一片備受檢視的岩石露頭──獲致的發現，可能有助於回答這些問題，此一發現記載於期刊《天體生物學》本週於網路上發表的一篇論文裡。 |
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It centers on something called microbially induced sedimentary structures, commonly shortened to the acronym MISS. |
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It's a mouthful to many, but scientists believe this phenomenon could be the key to finding the first demonstrable evidence of life. |
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這項發現的焦點在於一種稱為「微生物成因沉澱構造」的東西，通常以字首簡稱為 MISS。這個名稱對許多人而言很拗口，但科學家認為這種現象可能是找出生命最早出現證據的關鍵所在。 |
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A MISS forms via a process involving microorganisms found in what's called microbial mats formed within rocks or sediment, something that can only happen under certain conditions. |
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MISS 形成的過程涉及一種微生物，這種微生物生存在所謂的微生物墊裡。微生物墊形成於岩石或沉澱物中，而且只有在特定條件下才有可能出現。 |
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As the study's lead author, Nora Noffke of Old Dominion University, notes, "The signal of early life forms has been preserved more clearly in MISS compared with other prehistoric finds. |
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Another unique thing about them, unlike some other geological phenomena, is that a MISS structure formed a few billion years ago can look much like one a few hundred-thousand years old." |
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這項研究的主要作者是老道明大學的諾拉．諾福克，她指出：「相較於其他史前時代的發現，保存在 MISS 中的早期生命型態徵象比較清楚。MISS 結構還有另外一個不同於其他部分地質現象的獨特之處就是，於幾十億年前形成的 MISS 結構看起來很像是於幾十萬年前形成的。」 |
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