新概念英语第三册 less55_new

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[00:00.00]喜欢chazidian.com，就把chazidian.com复制到QQ个人资料中！Lesson 55 From the earth: Greetings
[00:07.14]55 来自地球的问候
[00:14.29]Listen to the tape then answer the question below.
[00:17.23]听录音,然后回答以下问题.
[00:20.17]Which life forms are most likely to develop on a distant planet?
[00:27.10]什么生命形式最可能在遥远的行星上得以生存?
[00:34.04]Recent developments in astronomy
[00:36.31]天文学方面的最新发展
[00:38.58]have made it possible to detect planets in our own Milky Way and in other galaxies.
[00:42.41]使我们能够在银河系和其他星系发现行星.
[00:46.24]This is a major achievement because,in relative terms,
[00:49.21]这是一个重要的成就,因为相对来说,
[00:52.19]planets are very small and do not emit light.
[00:54.92]行星很小,而且也不发光.
[00:57.65]Finding planets is proving hard enough,
[01:00.13]寻找行星证明相当困难,
[01:02.62]but finding life on them will prove infinitely more difficult.
[01:05.65]但是要在行星上发现生命会变得无比艰难.
[01:08.68]The first question to answer
[01:10.56]第一个需要解答的问题
[01:12.44]is whether a planet can actually support life.
[01:15.06]是行星是否有能够维持生命的条件.
[01:17.69]In our own solar system,for example,
[01:19.91]举例来说,在我们的太阳系里,
[01:22.13]Venus is far to hot and Mars is far too cold to support life.
[01:26.30]对生命来说,金星的温度太高,而火星的太低.
[01:30.46]Only the Earth provides ideal conditions,and even here
[01:33.60]只有地坏提供了理想的条件,而即使在这里,
[01:36.73]it has taken more than four billion years for plant and animal life to evolve.
[01:40.31]植物和动物的进化也用了40多亿年的时间.
[01:43.89]Whether a planet can support life
[01:43.39]一颗行星时否能够维持生命
[01:42.89]depends on the size and brightness of its star,that is its 'sun'
[01:46.61]取决于它的恒星--即它的"太阳"--的大小和亮度.
[01:50.33]Imagine a star up to twenty times larger,
[01:53.06]设想一下,一颗恒星比我们的太阳还要大,
[01:55.79]brighter and hotter than our own sun.
[01:58.17]还要亮,还要热20倍,
[02:00.55]A planet would have to be a very long way from it
[02:03.13]那么一颗行星要离它的恒星非常远
[02:05.72]to be capable of supporting life.
[02:07.74]才能维持生命。
[02:09.77]Alternatively,if the star were small,
[02:12.30]反之,如果恒星很小,
[02:14.84]the life-supporting planet would have to have a close orbit round it
[02:17.92]行星就要在离恒星很近的轨道上运行,
[02:21.00]and also provide the perfect conditions for life forms to develop.
[02:24.03]而且在有极好的条件才能使生命发展.
[02:27.06]But how would we find such a planet?
[02:29.24]但是,我们如何才能找到这样一颗行星呢?
[02:31.42]At present,there is no telescope in existence
[02:33.91]现在,没有一台现存的望远镜
[02:36.39]that is capable of detecting the presence of life.
[02:38.82]可以发现生命的存在.
[02:41.25]The development of such a telescope
[02:43.53]而开发这样一台望远镜
[02:45.82]will be one of the great astronomical projects of the 21st century.
[02:49.10]将会是21世纪天文学的一个重要的研究课题.
[02:52.37]It is impossible to look for life on another planet using earth-based telescopes
[02:55.76]使用放置在地球上的望远镜是无法观察到其他行星上的生命的.
[02:59.14]Our own warm atmosphere and the heat generated by the telescope
[03:02.56]地球周围温暖的大气层和望远镜散出的热量
[03:05.98]would make it impossible to detect objects as small as planets.
[03:08.96]使得我们根本不可能找到象行星那么小的物体.
[03:11.94]Even a telescope in orbit round the earth,
[03:14.17]即使是一台放置在围绕地球的轨道上的望远镜--
[03:16.41]like the very successful Hubble telescope,
[03:18.89]如非常成功的哈勃望远镜---
[03:21.37]would not be suitable because of the dust particles in our solar system.
[03:23.93]也因为太阳系中的尘埃微粒而无法胜任.
[03:26.49]A telescope would have to be as far away as the planet Jupiter
[03:29.72]望远镜要放置在木星那样遥远的行星上
[03:32.94]to look for life in outer space,
[03:35.12]才有可能在外层空间搜寻生命,
[03:37.31]because the dust becomes thinner
[03:39.29]因为尘埃越稀薄,
[03:41.28]the further we travel towards the outer edges of our own solar system.
[03:44.40]我们就越是接近太阳系的边缘.