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背景介绍

众所周知，水是生命之源。人类对太空系外行星的探索已经有数百年的历史了，天文学家们已经发现了许多可能适宜人类生存的系外行星，但却一直未发现液态水的存在。如今，天文学家们终于发现了首颗有水存在的系外宜居行星，太空移民或指日可待。

the first planet beyond the solar system confirmed to have water

太阳系外首颗被证明有水存在的行星

since its discovery by astronomers in 2015, the exoplanet k2-18b has elicited much excitement.

自从2015年天文学家发现了k2-18b以来，这颗系外行星就让许多人为之兴奋。

swirling around a red-dwarf star about 110 light-years away from earth, the distant world sits in a so-called goldilocks zone—not close enough to its host star to be too hot and not far enough away to be too cold—that could allow liquid water to flow across its surface. that is a crucial condition for life as we know it.

这颗遥远的行星围绕着一颗距地球约110光年的红矮星旋转，它处于该星系所谓的“宜居带”上（距离其恒星不算太近，因而不会太热；也不算太远，因而不会太冷），这使其表面有了存在液态水的可能。众所周知，水是孕育生命的关键条件。

now astronomers have cranked up the speculation. follow-up images taken by the hubble space telescope suggest k2-18b has an atmosphere containing large amounts of water vapour—the first exoplanet in a habitable zone to have this confirmed.

如今，天文学家们开始进行更大胆的推测了。哈勃太空望远镜所拍摄的后续图像显示，k2-18b的大气层中含有大量的水蒸气——这是首颗被证实有水存在的处于宜居带上的系外行星。

most exoplanets previously found with atmospheres have been gas giants, similar to neptune or jupiter. k2-18b instead looks like it could be a rocky planet twice as big as earth, perhaps covered in vast ice-covered seas.

以前发现的大多数有大气层的系外行星都是类似于海王星或木星的气态巨行星。而k2-18b看起来像是一颗地球两倍大小的岩质行星，其表面可能被广阔的冰雪海洋所覆盖。

writing this week in nature astronomy, dr tsiaras describes how his team wrote software that could analyse the data collected by hubble to try to do the same job—up to a point. they were not able to pinpoint the exact form and amounts of the water they found.

席亚拉博士本周发表在《自然天文学》杂志上的文章描述了他的团队如何编写软件对哈勃望远镜所收集的数据进行分析的，利用软件在一定程度上完成重复性的工作。他们无法得出所发现的水的确切形态和含量。

instead they used computer models to simulate the most likely scenarios, and concluded that as much as half of the atmosphere of k2-18b could be water vapour. they also found evidence of large amounts of hydrogen and helium gas.

于是，他们利用计算机模型来模拟最有可能的情况，最终得出结论：k2-18b大气中高达一半的成分是水蒸气。此外，他们还发现了存在大量氢气和氦气的证据。

this is just the start of such study of planets beyond our solar system. astronomers plan to launch two new orbiting telescopes in the next decade—the american james webb space telescope and the european ariel survey—that will be powerful enough to peer into the atmospheres of exoplanets more closely. powerful enough, perhaps, to detect telltale molecular signatures of life.

这只是对太阳系外行星探索的开端。天文学家计划在未来十年发射两架新的轨道望远镜（美国的詹姆斯·韦伯太空望远镜和欧洲的阿里尔太空望远镜），这两架望远镜足以让人们更近距离地观察系外行星的大气层。它们说不定强大到足以探测生命的分子特征。

with dr tsiaras’s analysis, k2-18b is now the best candidate for a life-supporting exoplanet out there. the temperature on the surface could be about the same as earth and there could be similar clouds hanging in the sky.

据席亚拉博士分析，k2-18b目前是适宜生命生存的系外行星的最佳候选者。其表面温度可能和地球差不多，天空上可能也有类似的云。

however, the planet’s adjacency to the star—it whizzes around once every 33 days—could produce intense space weather from the stellar activity. and it would be advisable to pack sun cream: the ultraviolet ra

diation would be off the scale.

然而，由于它离恒星比较近（每33天绕恒星一圈），可能会因为恒星活动而导致强烈的空间气象。此外，如果前去最好把防晒霜带上，那边的紫外线辐射可能会超标！

(红色标注词为重难点词汇)

重难点词汇：

pinpoint [?p?np??nt] vt. 查明；准确描述 adj. 精确的；详尽的 n. 针尖；精确位置；极小之物

telltale [?telte?l] adj. 报警的；泄密的；搬弄是非的 n. 迹象；指示器；搬弄是非者

adjacency [?’d?esnsi] n. 毗邻；四周；邻接

本文翻译：vinnie

校核：vinnie

编辑：vinnie

小编说

自从1609年伽利略发明了第一架太空望远镜，人类开始了对宇宙太空的探索。而1990年送上太空的哈勃空间望远镜让人类得以对太空进行更深入的探索。如今，经过天文学家的不断努力，我们终于发现了首颗有水存在的系外宜居行星，距离人类的星际移民又迈出了一步。

来源:每日双语经济学人

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