Scientists now say that an ocean several miles deep once covered a third of the surface of the planet, enough water to support the origin and evolution of life.科學家們現在說遠洋幾英里深處，一旦涵蓋了三分之一的表面的星球，足夠的水，以支持起源和進化的生命。 The red planet, they said, had once been a deep blue, just like Earth.這個紅色星球時，他們說，曾一度成為深藍色，就像地球。

By Steve Connor由史蒂夫康納

For generations, people have been fascinated by the idea of life on Mars.世世代代，人們一直嚮往的想法生活在火星上。 It began in earnest in the late 19th century when an Italian astronomer called Giovanni Schiaparelli peered through his telescope and saw long, straight lines etched on to the surface of the red planet.它才真正開始，在19世紀後期的時候，一個意大利天文學家喬萬尼所謂schiaparelli peered通過他的望遠鏡，看到長，直線鐫刻到地表的紅色星球。 He called them “canali” and others quickly became convinced that an alien civilisation had built a sophisticated network of canals, perhaps to move water from one region of Mars to another.他呼籲他們" canali "等，很快就成為堅信，一個外來文明已建成了先進的網絡，挖掘運河，也許動議水從一個地區的火星到另一個地方。

In 1897, HG Wells published The War of the Worlds, which describes an invasion of Martians covetous of Earth’s rich natural resources. 1897年，汞，砷水井公佈了世界之戰，其中描述了侵華戰爭，火星人覬覦地球的豐富天然資源。 When Orson Welles broadcast his famous radio adaptation of the book in 1938, mass panic ensued when thousands of Americans truly believed that the Earth was under attack by Martians.當此前播出他的著名電台改編這本書在1938年，大眾都很慌張，當成千上萬的美國人真的認為地球是根據攻擊火星人。

The true nature of Mars, however, emerged in the late 1960s when the Mariner space missions paid the first visits to Earth’s smaller neighbour.真實性質的火星，不過，出現在上世紀60年代末，當水手航天飛行任務付出了第一次訪問地球的規模較小的鄰居。 Mars turned out to be heavily cratered, dotted with extinct volcanoes, colder than Antarctica and, crucially, drier than the Atacama desert - the driest place on Earth.火星後來被大量cratered ，點綴著死火山，更冷，比南極洲，最重要的是，少雨，比阿塔卡馬沙漠-乾燥的地方，在地球上。

Mars was a dead place, a desiccated wasteland sterilised by harsh solar radiation.火星是個死的地方， desiccated荒地消毒，由嚴苛的太陽輻射。 Anything approximating to a biological molecule on the Martian surface would be instantly irradiated.什麼逼近到一個生物分子對火星表面的，將即刻照射。 There were certainly no canals, no water and quite evidently no life - or, at least, not life as we know it.有肯定沒有運河，沒有水，很顯然，沒有生命-或至少沒有生命，因為我們知道這一點。

When the Viking spacecraft visited Mars in the 1970s they confirmed this view of a lifeless planet.當海盜飛船前往火星，在20世紀70年代，他們證實了這一觀點沒有生命的星球。 Viking images depicted a bitterly cold, dry landscape of rock and dust, but they also showed another feature that began a fresh debate over whether Mars was always such a dead planet.維京人形象描繪了寒風凜冽，山水的岩石和塵埃，但它們也顯示，另一項特色即開始了一個新的爭論是否火星一直是這樣一個死星球。 They detected what seemed to be the shorelines of ancient oceans - and where there was liquid water, there was a strong possibility of life.他們發現什麼，似乎成為大陸海岸線的古海洋-那裡有液態水，有一種強烈的可能性的生活方式。

Yesterday, American and Canadian scientists reignited the debate over whether there was ever a giant ocean of liquid water on Mars.昨天，美國和加拿大科學家參會辯論是否曾經有一種巨型海洋的液態水在火星上。 According to a study published in the journal Nature, an ocean several miles deep once covered a third of the surface of Mars - easily enough water to support the origin and evolution of life.根據一項研究的結果公佈在Nature雜誌上，海洋是幾英里深，一旦涵蓋了三分之一的火星表面的-輕鬆足夠的水，以支持起源和進化的生命。 The red planet, they said, had once been a deep blue, just like Earth.這個紅色星球時，他們說，曾一度成為深藍色，就像地球。

The Viking probes of 25 years ago detected two possible ancient shorelines near the poles of the planet.維京探針在25年前發現有兩種可能的古海岸線附近波蘭人的星球。 The shorelines stretched for thousands of kilometres around what looked like dried-up ocean basins.該海岸線伸展，為數千公里左右，看上去好像乾涸了海洋盆地。 Each shoreline had the distinctive “edges” separating the rugged, weathered landscape of dry land from the smoother, sediment-filled seabed.每個海岸線有獨特的"邊緣"政企分開凹凸不平，風化景觀的旱地，從流暢，泥沙填充海底。

The similarity to features seen on Earth were obvious for all to see.相似性，以特色上看到的地球是顯而易見的，大家有目共睹。 The Viking probes had mapped two Martian shorelines - one called Arabia and the other named Deuteronilus - and scientists dated them to be between two and four billion years old.維京探頭已制訂兩個火星海岸線-一個所謂的阿拉伯及其他命名d euteronilus-和科學家過時，他們將在2至四十億年歲。

However, a major problem soon emerged.然而，一個主要問題，很快出現了。 In the 1990s, Nasa’s Mars Global Surveyor mapped the topography of Mars to a resolution of 300 metres and it quickly became apparent that the two “shorelines” varied in elevation by almost two miles.在20世紀90年代，美國航天局的火星全球測量師繪製的地形火星的一項決議， 300米，它很快變得明顯，這兩個"海岸線"都各有不同，海拔由近2英里。 Differences in height between shorelines on Earth were well known - caused by variations in global sea levels - but the dramatic difference on Mars made it highly unlikely that these “shorelines” were created by an ancient ocean.差異高度之間的海岸線，對地球是眾所周知的-所造成的差異，使全球的海平面上升-但戲劇性的差異對火星作出的，它極不可能的，這些"海岸線"的人所創造的一個古老的海洋。

The topographic reality revealed by the Mars Global Surveyor became the biggest stumbling block to the notion that Mars was once smothered in water.地形現實，揭示了火星全球測量師，成為國內最大的絆腳石概念，即火星曾經扼殺在水中。 It was also a blow to the idea of Martian life, because without water in liquid form it was difficult to see how life could ever get going in the first place, never mind evolving into even the most simple of microbial lifeforms.這也是一個打擊的想法火星上可能存在生命，因為，如果沒有水的液態形式，它是很難看到生命如何能獲得去擺在首位，永遠銘記演變成即使是最簡單的微生物的生命形式。

The latest study seems to have lifted this barrier to the idea of an ocean on Mars.最新研究似乎已解除這一障礙的想法是一個海洋火星上。 Scientists at the University of California, Berkeley, the University of Toronto and the Carnegie Institution in Washington have offered a powerful explanation for why the two ancient shorelines of Mars are separated by such dramatically different elevations.科學家們在加利福尼亞大學伯克利分校，加拿大多倫多大學和卡內基學會在華盛頓提供了有力的解釋，為什麼這兩個古老的大陸海岸線，火星相距這種明顯不同海拔地區。

They have shown that the axis of spin of Mars, which determines the position of the true poles rather than the magnetic poles, has varied by as much as 50 degrees during the long geological history of the planet.他們表明，這一軸線旋轉的火星上的，這就決定了立場，真正的一極，而非磁極的，有不同的，由高達50攝氏度，在漫長的地質歷史上的這個星球。 In other words the shorelines have moved around because the planet itself has in the past shifted significantly on its axis - resulting in huge changes to the shape of the Martian landscape and its shorelines.在換句話說，大陸海岸線，有動議，因為這個星球本身已在過去大量轉移到其軸心-造成巨大的變化，從而形成的火星地貌和海岸線。

“When the spin axis moves relative to the surface, the surface deforms, and this is recorded in the shoreline,” explained Professor Michael Manga, of the University of California, Berkeley. "當自轉軸動作相對到地表，地表變形，而這是記錄在海岸線解釋說： "教授邁克爾漫畫，在美國加州大學伯克利分校。

Planets such as Earth and Mars have an outer shell, or lithosphere, and a change in the spin axis can cause the solid surface to deform differently than the liquid ocean and this explains the warped shorelines, according to Taylor Perron, the lead author of the study, who is now at Harvard University.行星如地球和火星上有一個外殼，或者岩石圈，並改變在自轉軸可以導致固體表面，以不同的變形比液態海洋與這解釋了歪大陸海岸線，據泰勒Perron的，牽頭的作者之一研究中，他現在在美國哈佛大學。

“On planets like Mars and Earth with an outer shell, or lithosphere, that behaves elastically, the solid surface will deform differently than the sea surface, creating a non-uniform change in the topography,” Dr Perron said. "行星像火星和地球形成了一個外殼，或者岩石圈，守規矩的彈性，固體表面會發生變形不同於海面，形成了非均勻變化，在地形， "博士Perron的說。

Jerry Mitrovica of Toronto University said that the evidence is now so overwhelming that this can explain why the shorelines of Mars formed at such dramatically different heights - more than a mile difference in elevation.傑里米特羅維察的多倫多大學表示，此證據是，現在如此壓倒性的，這可以解釋為什麼大陸海岸線的火星在形成這種戲劇性不同高度-超過一英里的不同高程。

“At some point in the planet’s history, a major shift of mass caused the pole to wander about 50 degrees towards its current location and the resulting change in orientation dramatically warped the topography and the ancient shorelines,” Professor Mitrovica said. "在某個時刻，在地球的歷史上，一個重大的轉變對群眾造成了極以徜徉在50攝氏度對目前所在位置及由此而改變方向，極大地扭曲的地形和古老的大陸海岸線， "教授說，米特羅維察。

One critical piece of evidence in support of this hypothesis is the position of the immense Tharsis volcano on Mars - the biggest in the Solar System and some 10,000 times bigger than Mauna Loa, the biggest volcano on Earth.其中一個關鍵性的證據支持這一假設的，是立場的巨大塔爾西斯火山火星-最大的太陽能系統及約一萬倍，大於莫納羅亞火山，其中最大的火山地球。 Tharsis is so massive that it will always reorient itself to sit on the planet’s equator - it will be spun out to the widest point on the axis of spin, just like a centrifuge.塔爾西斯是如此龐大，我們黨就能永遠調整自己坐於行星的赤道-它將會失控，以最廣泛的角度對軸的旋轉，就像一個離心機。 The scientists found that their assessment of how the position of the Martian poles has moved matches precisely the movements of Tharsis as it keeps shifting to maintain its place on the changing position of the equator.科學家們發現，他們的評價如何的立場與火星兩極搬到比賽中，正是運動的塔爾西斯因為它發生微妙的變化，以維持其位置就改變立場的赤道。

“The chances of this happening randomly are less than 1 in 10,000,” Professor Mitrovica said. "的機會，這種情況發生，隨機均小於1 ，在10000 ， "教授說，米特羅維察。

As yet the scientists do not understand why the spin axis of Mars moved so much.但科學家們不明白為什麼自轉軸的火星提出了這麼多。 It may have resulted from a massive deluge of water on the Martian surface resulting in the first Arabia shoreline.它可能造成大規模氾濫的水對火星表面造成的，在第一阿拉伯海岸線。 The shift in weight caused the planet to tilt on its axis.轉移重量造成地球以傾斜，其軸心。 Once the water disappeared, the pole could have shifted back, then shifted again as a second deluge created the Deuteronilus shoreline.一旦水消失，極可能已轉移回來，然後再轉向作為第二雨淋創造了deuteronilus海岸線。 “What we don’t know is what caused the poles to shift on Mars and what happened to the water. "什麼，我們不知道是什麼造成了極點，以轉移對火星和所發生的事情，以水。 The ocean may have been gradually converted into water vapour, moved to higher elevations, and flowed beneath the surface.海洋可能已逐漸轉化為水蒸汽，遷移到高海拔地區，並流到下方地面。 There could be a large mass of water deep within Mars,” Dr Perron said.有可能是一個大質量的水深處火星， "博士Perron的說。

But what happened to the water on Mars is critical in the assessment of whether there is still life on the planet.但接下來發生的，以水在火星上是至關重要的，在評估是否仍然有生命的星球。 Many scientists believe there is a strong chance that if liquid water exists deep under the surface of Mars, there is a good chance that simple lifeforms may still be living underground.許多科學家認為，是有一個堅強有力的機會，如果液態水存在的深層根據火星表面的，有一個很好的機會簡單的生命形式可能仍然生活在地下。

At the end of last year, Nasa scientists analysed successive satellite images of craters on Mars that appeared to show erosion marks caused by streams of liquid water bubbling up from under the surface of Mars and flowing down the sides of the crater.截至去年年底，美國航天局的科學家分析了歷次衛星圖像的環形山火星上似乎顯示侵蝕痕跡造成溪流中的液體水起泡了，從火星表面和流水下來，雙方的彈坑。 The scientists were convinced that these marks were not simply created by the movement of dry dust.科學家們相信，這些商標並非僅是單純的製造出來的運動乾燥塵埃。

This finding came on top of a succession of studies pointing to the possibility that water must have flowed on the surface of Mars.這一發現前來再加上一連串的研究報告指出，可能水要流於火星表面。 And now the major obstacle to the idea of a massive ocean on Mars has been removed.而目前主要的障礙在於理念的大規模海洋火星上已經移除。 It really does seem that the red planet was once a water-rich world, and that some of this water may still be present in underground deposits.確實，似乎這個紅色星球曾經是一個水資源豐富的世界，而一些本水仍可能存在於地下存款。

But what does this mean for life?但是，這是什麼意思，為生活嗎？ The point is that without water in its liquid form it is difficult to imagine that life could exist.問題的要點是，沒有水，在其液態形式，這是很難想像生活中可能存在的。 Water does not make life obligatory, but it does make it far more likely.水不使生活強制性的，但它確實令它遠遠的可能性就越大。 As yet the only direct evidence for life on Mars has been highly controversial.迄今為止唯一的直接證據，為生活在火星上已經引起極大爭議。 Ten years ago, Nasa scientists announced that they had found possible signs of life on a Martian meteorite called ALH84001. 10年前，美國航天局的科學家12日宣布，他們已經找到了可能的生命跡象的一個火星隕石所謂alh84001 。 The potato-sized lump of rock fell to Earth 13,000 years ago and a detailed analysis threw up chemical signatures of life, as well as rod-shaped structures that looked like terrestrial bacteria, but smaller.土豆大小的一塊岩石下滑至地球1.3萬年前，並詳細分析投擲了化學簽字的生活方式，以及桿狀結構看上去像陸地細菌，但規模較小。

Other scientists have been bitterly critical of this analysis, which has gone through a series of claims and counterclaims concerning its authenticity.其他科學家一直痛批這種分析，並經歷了一系列的索賠與反索賠有關其真實性。 The only way of truly solving this problem is to look for a similar piece of rock on Mars and bring it back to Earth for analysis.唯一的辦法，真正解決這個問題是要尋找一個類似的一塊岩石上火星並把它發回地球進行分析。 And the best place to find Martian fossils is in sedimentary rock formed by an ocean.和最好的地方，尋找火星化石是在沉積岩形成的一個海洋。 At least scientists looking for life on Mars now have a better idea where to find it.至少科學家尋找生命的火星上，現在有一個更好的理念在哪裡能找到它。

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