地球上的生命有可能来自Ceres(谷神星)吗？

继续翻译...

Looking at the evidence

Early in the history of the solar system was a period known as Late Heavy Bombardment, a turbulent time when cataclysmic asteroid impacts were common. If there was life on Earth before this dangerous era, it was most likely eradicated and had to begin again after much of this cosmic debris had cleared out of the inner solar system. Interestingly, evidence indicates that Ceres avoided being pummelled by devastating impacts during this time. If it had been bombarded, it would have completely and forever lost its water mantle, as its gravitational force is too weak to recapture it. This is probably what happened to the asteroid Vesta, which has a very large impact crater and no water.

"The evidence points to Ceres having remained relatively unscathed during the Late Heavy Bombardment," states Houtkooper. He says this means Ceres still could have "a water ocean where life could have originated early in the history of the solar system."This leads to an interesting hypothesis. If the Earth was sterilized by colossal impacts, but Ceres hosted life which survived, could the dwarf planet have reseeded our world with life, via rock fragments that chipped off Ceres and then crashed into Earth? Are all organisms on Earth, including humans, descendants of Ceres? This is an idea that Houtkooper had to pursue.

"I looked at the different solar system bodies which either had or currently have oceans," he explains. "The planet Venus probably had an ocean early in its history, but the planet's greater mass means that more force is needed to chip off a piece of the planetary crust and propel it in the direction of the Earth. Smaller objects like Ceres have lower escape velocities, making it easier for parts of it to be separated."

Houtkooper then calculated the orbital paths of candidate planets, moons and asteroids to see which were in the best positions to have pieces successfully reach the Earth, without being intercepted by other objects. Ceres fared favourably in these calculations.

Life on Ceres

Finally, Houtkooper considered the possibility of organisms still being present on Ceres. "In the ocean, there could be life," he suggests. "On the surface, it would be more difficult. But there are some possibilities. There could be hydrogen peroxide-based life, able to withstand the low temperatures." It's not currently known whether hydrogen peroxide is present on Ceres, but nothing rules it out, either.

The thought of Earth being seeded with life from Ceres and creatures existing there today is certainly fascinating, but Houtkooper admits that it is more science fiction than science fact until evidence can be provided. This is naturally difficult to obtain, as Ceres is a small and distant world. Even the best current images contain very little detail, and just show that there are some surface features; what these features are exactly is a mystery. Spectral analyses indicate the presence of clay-like minerals, and Ceres' slightly flattened shape is what we would expect from a world with a rocky core below a layer of water or ice. Ceres is a dwarf planet with many secrets.

Fortunately, this will soon change thanks to NASA's Dawn mission。 Launched in 2007, the probe is due to arrive at Ceres in 2015. Once there it will shed light on the mysterious world, and perhaps take photographs of geysers of water erupting from the surface. Its close-up view could indicate whether Ceres really does have the potential for life.

寻找证据

太阳系早期的历史是一段晚期重型轰击的时期，是一段小行星灾难性撞击频繁发生的狂暴时期。如果在这段危险时期之前地球上已有了生命，那么它们很有可能会发生灭绝，不得不在这些宇宙残迹被大部分清除出太阳系内部之后重新开始。有趣的是，证据显示Ceres(谷神星)在这段时期避开了这种灾难性的撞击，如果它曾经被撞击过，那么它将完全、永久的失去它的水性地幔，因为它的重力太小了无法再次虏获水源。这可能发生在了小行星Vesta(灶神星)上，因为它就有个非常大的撞击坑，同时没有水。

“证据指出在晚期重型轰击中，Ceres仍保持着相对没有被撞击的状态，” Houtkooper说，他说这就意味着在太阳系的历史早期，Ceres可能已经拥有了一个孕育生命的水性海洋。这就产生了一个有趣的假说。如果地球被巨大的撞击导致了不育（：）），但是Ceres上的生命却存活了下来，那么这颗矮行星能通过其破裂的岩石碎片，后撞击地球把生命的种子再次播种到我们的世界中来吗？地球上的生物体，包括人类，会是Ceres的后裔吗？这些都是Houtkooper不得不探究的问题。

“我研究了一些曾经有过或是近期还存有海洋的不同的太阳系”他解释到，“金星在它的历史早期可能有过海洋，但是行星的体积越大，那么受到小行星撞击后产生碎片，同时驱使碎片进入撞击地球的轨道，所需要的力量就会越大”。越小的物体，比如Ceres，就有着较低的逃逸速度，这就使它的部分结构更容易被分离。

Houtkooper之后又计算出了相关行星，卫星以及小行星的轨道，寻求碎片不会被其他物体截获，能成功到达地球的最好位置。Ceres在这些计算中一切都非常顺利。

Ceres上的生命
最终，Houtkooper认为在Ceres上还有生物体依然存在的可能性。“在海洋中可能还有生命”，他说，“在星体的表面存在生命可能会有一些困难，但是依然存在着可能性”。它们可能是以过氧化氢来维持的生命，能抵抗的住低温。目前，在Ceres上是否存在双氧水还不知道，但是也没有任何证据能说明其不存在。

地球上生命来自Ceres，以及Ceres上依然存有生命的想法确实很吸引人，但是Houtkooper也承认在证据被提出之前，这种想法更像科幻小说。这些证据很难获得，因为Ceres是个很小且很遥远的世界，即使目前最好的照片包含的细节也非常的少，仅仅显示出了一些其表面的特征，而这些特征是什么也的确是个迷。光谱分析说明它有一些粘土样的矿物质存在，同时Ceres稍稍扁平的外形也正是我们想从在水或是冰的下层有岩状内核的星体中所期待看到的。Ceres就是这样的一个充满神秘的矮行星。

幸运的是，这些情况将随着美国航空航天局的“黎明计划”（ Dawn Mission是NASA计划已久的一项太空任务,目的在于探索太阳系的小行星带,尤其是其中的两个主要天体--Ceres和Vesta）发生变革。发射于2007年，探测器将会在2015年达到Ceres。一旦达到，探测器就会使我们搞清楚这个神秘的世界，同时它也有可能会拍摄到一些水喷出Ceres表面的照片，它的特写镜头会揭示出Ceres是否真的会有生命的存在。（The  end）

第一次在翻译版发帖 请批评婉转些 别打击积极性 谢谢各位了 多指正 没翻完 较忙 希望能尽快继续

  Astrobiologists hope to find life elsewhere in the universe, or possibly even in our own cosmic neighborhood, the solar system. Their efforts are usually concentrated on worlds such as the planet Mars, or icy moons like Europa . However, there are other, less conventional locations in the solar system where scientists think life may be found.

  天文生物学家希望在宇宙的其它地方能够发现生命，甚至是在我们太阳系的其它邻居那能有所发现。他们的努力通常集中在火星或是冰冷的卫星Europa 上。然而，在太阳系其它一些非常规考虑的地方科学家们也相信可能会生命迹象的存在。

  At the International Society for the Study of the Origin of Life conference in Florence, Italy, from the University of Giessen Joop Houtkooper divulged a theory that life could have originated on the asteroid. The distant world Ceres, the smallest known dwarf planet in the solar system, lies within the asteroid belt. It was called a planet after its discovery in 1801, then later downgraded to asteroid status. With the latest planet definition from the International Astronomical Union, the round object is now considered a dwarf planet. Is there a chance that this exotic world is home to extraterrestrial organisms?

  在意大利弗洛伦撒举行的生命起源研讨会议上，来自Giessen大学的Joop Houtkooper就提出生命可能起源于小行星Ceres遥远的行星Ceres，太阳系中已知的最小的矮行星，位于我们的小行星带中。在1801年发现时认为是行星，之后被降级为小行星，根据最新的国际天文学会对行星的定义，这颗圆的星体又被重新定为矮行星，这么一个奇异的世界会有可能是外来生物体的家园吗？

  "This idea came to me when I heard a talk about all the satellites in the solar system that consist of a large part of ice, much of which is probably still in a liquid state,"Joop Houtkooper says. "The total volume of all this water is something like 40 times greater than all the oceans on Earth."

  Houtkooper说：“当我听说太阳系中所有的卫星都含有冰，并且其中的大部分有可能呈液态的时候，我就产生了我的这种想法。所有这些水的总量是地球上全部海洋含水量的四十倍。”

This reminded Joop Houtkooper of a theory about how life originated. Organisms may have first developed around hydrothermal vents, which lie at the bottom of oceans and spew hot chemicals. Many icy bodies in our solar system have rocky cores, so they may have had or still have hydrothermal vents. realized, "if life is not unique to the Earth and could exist elsewhere, then these icy bodies are the places where life may have originated."

这促使Houtkooper酝酿出了生命是如何起源的理论，生物体可能最早来自于位于海洋深部、能喷出热化学物质的热水孔。在我们太阳系中的很多冰体都有着岩石般的内核，所有它们可能曾经甚至是现在都还存在着这种热水孔。Houtkooper认识到：如果生命对于地球来说不是唯一的，是可以存在于其他地方的，那么这些冰体就有可能是生命最初产生的地方。（to be continued…）

最近比较忙乱，看到晚了。：）

先鼓励一下SUYAYANSHU同学的翻译，希望再接再厉，熟悉天文翻译的套路，如果熟悉了很多专业名词，以及中英文的一些习惯表达法之后，应当来说会逐渐顺利的。

人名我很倾向使用 ...
shn_117 发表于 2009-3-25 10:53

                               
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谢谢shn_117 第一次翻译什么都不是很懂 第二次传上去的时候也还没看你的建议 但是还是改进了一点点 ：）希望继续鼓励 谢谢

楼主有没有可能参照我们常常采用的中英文间隔排版方式？

那样看起来方便省力。
shn_117 发表于 2009-3-25 12:15

                               
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没有啊 什么意思啊 我已经在第一篇里回你了 刚刚开始 你就多多教教吧

呵呵  翻译得不错诶~~~
caihong325 发表于 2009-3-25 12:12

                               
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谢谢啊 好高兴啊 又吃成长快乐了

5# suyayanshu
我是来学习的~
那个那个……成长快乐是什么东东？

7# 一分半 就是灵泛得乐！ LZ真的很强大！貌似那人是说你能不能一段英文，一段中文的翻！这样方便大家学习你是如何翻译原文的！

oh  got it 下次改进  谢谢
一分半 --- 成长快乐是个广告啊  

大家怎么都在谈论翻译得好不好呢？
我觉得这篇文章的内容是重点…
如果真是这样，真正的地球人去哪里了…？

11# 幽哎浮欧
所谓地球人就是在地球上进化出来的人，但不一定就是在地球土生土长的~说不定你才是真正的地球人

11# 幽哎浮欧

额，根据本版定位，主要是发布译文和讨论交流翻译经验的，知识性讨论到相关版块进行。说起来翻译经验交流的还是少了点，讨论知识性的东西反而比较多了。

12# 一分半

可以参考部分国家的永久居民权获取途径了，比如居住多少年就满足条件了，或者是在当地出生都可以。

我将LZ的两个帖子合并，并编辑1L，重新排版以便于阅读。LZ可以自己编辑另一帖子。

为使两贴译文靠的近一些，删除了部分帖子（拆分移动）。

13# shn_117 发帖时匆忙！都没细看，原来是版主啊！失敬失敬！我们一起等待LZ的续作吧！