（CNN）
Opinion by Sara Seager
Updated 0229 GMT (1029 HKT) September 15, 2020
A global view of the surface of Venus centered at 180 degrees east longitude. The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft.
朝東經180度拍攝的金星表面。色彩呈現系由蘇聯韋內拉13與14號太空船所拍攝之彩色照片模擬合成。
Editor's Note: Sara Seager is a professor of planetary science, physics and aerospace engineering at the Massachusetts Institute of Technology. The opinions expressed here are her own. Read more opinion at CNN.
編輯的話：沙拉．席格是麻省理工學院物理與航太工程行星科學教授。本文代表其個人觀點。更多觀點投書，請上CNN網站。
Venus is the brightest object in the night sky after the moon and has intrigued humans for thousands of years. The discovery of phosphine gas in Venus' atmosphere has just upped the planet's appeal.
金星是夜空中看似亮度僅次於月亮的星星，數千年來，人們一直對金星很感興趣。而發現金星大氣中含有磷化氫，又使得這顆行星更加吸引人。
I was a member of the multinational research team that announced the finding in Nature Astronomy on Monday, and my takeaway is that it indicates there is something highly unusual going on to produce phosphine -- either some completely unknown chemistry, or possibly some kind of microbial-type life. Each explanation, somehow, seems equally crazy.
我剛好是星期一在《自然天文學》雜誌發表此一發現的國際研究團隊成員之一，我的論點是，要製造這樣的磷化氫，暗示了有某些不尋常的事情正在發生：要馬是某種全新未知的化學反應，要不就是有微生物存在其中。兩種解釋聽來差不多瘋狂。
Phosphine is a gas made up of one phosphorus atom and three hydrogen atoms. Phosphine is toxic to any life on Earth that uses oxygen, including humans. It was used as a chemical warfare agent in World War I and is associated only with human industry (e.g. pesticides) or with life in oxygen-free environments. Phosphine is found coming from swamps and marshes and sludges. It is also found in animal guts and excrement -- for example in relatively high concentrations over penguin colonies. Phosphine has also been measured in the lab as coming from complex mixtures of bacteria.
磷化氫是由一個磷原子和三個氫原子所組成，它對所有地球上需要靠氧氣維生的生物，包含人類，都具有毒性，曾在一次世界大戰中被拿來當作化學武器。目前認為只有透過人工合成（就像合成殺蟲劑那樣），或是在無氧環境下生存的生物，才有可能產出磷化氫，像是沼澤、濕地或泥漿等環境，在動物的膽或糞便裡面也可以找到它的身影，例如在企鵝密集群聚的棲地裡。實驗室亦可以從細菌的複合物中檢測出硫化氫的蹤跡。
The finding is so astonishing because phosphine should not be present in Venus' atmosphere. Phosphine needs lots of hydrogen and the right temperatures and pressures to form -- conditions found on Jupiter and Saturn but not at all on Venus. My team at MIT exhaustively searched all known chemistry and did not find any way for phosphine gas to be easily produced on Venus. Planetary processes including volcanoes, lightning, meteorites entering Venus' atmosphere are also "no goes" in that some might produce the tiniest amount of phosphine but not nearly enough to match the observations.
Does this mean Venus has alien life in its atmosphere producing phosphine gas? Not necessarily.
這是否意味著金星上存在著生命，來製造硫化氫呢？不盡然。
Venus is a very hostile place for any kind of life as we know it. The surface is scorchingly hot -- far too hot for complex molecules needed to make up life. High above the surface, the atmosphere becomes colder and colder. On Venus there is a sweet spot at 48 to 60 km (30 to 37 miles) above Venus' surface, in the clouds, where the temperature is not too hot, not too cold, but just right for life.
就目前所知，對所有生命型態而言，金星都是非常嚴苛的環境。它的表面溫度極端灼熱，熱到複雜分子根本無法演化成最初的生命。在高層的大氣中，溫度下降許多，約在距離地面48至60公里（30至37英里）左右的高空，有一個「甜蜜帶」，那裡的雲層不會太熱，也不會太冷，剛剛好適合生命生長。
Even so, the environment is harsh. The atmosphere is, for example, 50 times drier than the driest places on Earth. The cloud droplets are made not of liquid water but of concentrated sulfuric acid. The acid environment is billions of times more acidic than the most acidic environments on Earth. Earth-life components including DNA, proteins, and amino acids would be instantly destroyed in sulfuric acid. Any life in the Venusian clouds would have to be made up of building blocks different than Earth life, or be protected inside a shell made up of sulfuric acid-resistant material such as wax, graphite, sulfur, or something else.
People have been speculating about the presence of life in the clouds of Venus for over 50 years, starting with Carl Sagan. Scientists are sometimes reluctant to openly admit their interest in such a fringe topic.
即使如此，那裡的環境還是相對嚴峻。舉例而言，那裡的乾燥程度比地球上最乾燥的地方還要再乾50倍；那裡的雲層不是由液態水組成，而是由蒸餾過的硫酸形成，酸度達到地球上最酸環境的數十億倍之高，在那樣的硫酸底下，像去氧核醣核酸DNA、蛋白質和胺基酸等生物基本要素都會立刻被摧毀。在金星生長的生物，必定建構在與地球生命截然不同的形態上，或是具有能夠抵禦硫酸的保護盾，例如蠟質、石磨、硫磺等等的外殼。
People have been speculating about the presence of life in the clouds of Venus for over 50 years, starting with Carl Sagan. Scientists are sometimes reluctant to openly admit their interest in such a fringe topic.
自從卡爾．薩甘以來，至今已超過50年時間，人們一直猜測金星上面是否存在著生命，雖然科學家們有時候羞於承認自己對這種冷門領域感興趣。
Yet our team lead Jane Greaves of Cardiff University in the UK purposely decided to search for signs of life on Venus by way of phosphine gas. She proposed to use the James Clerk Maxwell radio telescope (JCMT) on Mauna Kea in Hawaii to observe phosphine at radio wavelengths. By coincidence, my team at MIT had also been working on phosphine gas as part of a larger project trying to understand which gases on exoplanets -- planets orbiting stars other than the sun -- might indicate the presence of life. A mutual contact connected us.
不過我們的研究團隊負責人，英國卡迪夫大學的珍．格里夫斯，挑選了金星中的硫化氫作為研究對象，它提議將詹氏無線電望遠鏡（詹姆斯．克萊克．麥克斯威爾，JCMT）應用在夏威夷的莫那克亞天文台上，來觀測硫化氫的無線電波長。恰巧，我的麻省理工團隊也正為一個更大的計畫投入硫化氫研究，要探索那些氣體成分，可能顯示系外行星（指存在於太陽系以外的行星）有生命存在。這將我們串連了起來。
When I first learned of Jane's finding I simply didn't believe it. Nonetheless, my MIT team worked with Jane's team on a proposal to use the more powerful Atacama Large Millimeter Array (ALMA). When the data came back and was analyzed, the phosphine signal was even stronger than before. I was still so shocked, so astonished, but we now had to accept that the finding was real. We diligently pressed on to support our detection, continuing to work through and rule out chemical processes as the phosphine source, and double and triple-checking that no other gas could mimic the presence of phosphine gas.
當我第一次聽到珍的發現時，根本不以為然。儘管如此我的MIT團隊還是和珍的團隊一起執行另一項提案，打算運用更強大的阿塔卡瑪大型毫米波陣列望遠鏡來進行觀測的研究提案。在蒐集和分析數據結果後，這一次，硫化氫存在的跡象比之前更明顯。我雖然吃驚，但不得不承認這項發現是真的。我們竭盡所能檢驗各種支持證據，不斷地排除其他各種可能造成相同現象的化學反應，再三確認沒有其他氣體會產生與硫化氫相同的現象。
Our solar system has a growing number of bodies of interest in the search for life. NASA's Mars Perseverance rover is on its way to Mars to search for signs of ancient life. Jupiter's moon Europa, Saturn's moons Enceladus and Titan are each fascinating potential targets. Our finding of phosphine gas now raises Venus as just one more place to take seriously in the search for life beyond Earth -- maybe not so crazy after all.ne gas.
人們對探索太陽系生命的興趣持續攀高，美國太空總署的火星漫遊者正在前往火星尋找古生物殘跡的路上，木星的衛星歐羅巴、土星的衛星土衛二及泰坦星，都是極具吸引力的潛在目標。如今，我們對硫化氫的發現，讓金星成為外太空另一個真的可能有生命存在的地方，這一切或許沒有聽起來的那麼瘋狂。
• intrigue /ɪnˈtriːɡ/ 很感興趣，密謀奪權
• fringe /frɪndʒ/ 邊緣 fringe group/event/issue
•scorching /ˈskɔːtʃɪŋ $ ˈskɔːr-/ 極端灼熱
• diligent /ˈdɪlədʒənt/ 勤奮細心 careful and thorough
* reference: Longman Dictionary
#Jill Yang
留言