英语听力文摘 类地行星发现者
瑞士科学家米歇尔·梅耶带领欧洲科学家小组宣布发现了一颗新的可能适宜人类居住的星球，现在，他又制定了更大的目标：寻找地外生命的迹象。该发现小组的成员斯蒂凡·尤迪推测这颗新星表面可能富含液态水，但他指出，他的这种推测是以行星的形成方式为基础，而不是以任何的证据。梅耶认为还会发现许多被科学家认为可能适合人类居住的星球。但短期内，最重要的发现还是这颗与地球相似的低质量行星581c。581c大约是地球质量的5倍。但它仍然是至今太阳系外发现的最小的一颗行星。梅耶认为美国宇航局的“类地行星发现者”号和欧洲航天局的“达尔文”探测卫星将在寻找地外智慧生命上做出重要的贡献。
For a planet to support life, the planet must be located within its star’s habitable zone. That is, it must be located at a distance where the temperature would allow water to remain in liquid form.
At present we’ve identified about 250 extrasolar planets, and only two have appeared to be located close to or within this zone. And most of these extrasolar planets are about the size of Jupiter, not Earth. So, is Earth’s size and orbit unique? Unlikely. The problem is that planets the approximate mass and orbit distance of Earth are too difficult to detect using our current space technology.
However, telescopes in the works right now are being designed specifically to overcome the obstacles astronomers face detecting Earth-like planets. One such project is NASA’s Terrestrial Planet Finder, or TPF. TPF’s capabilities will include blocking out the glare of stars, making visible relatively tiny Earth-like planets orbiting them.
TPF will be able to search the habitable zones of stars located up to fifty light years away, analyzing the composition of planets’ atmospheres. It will look for gasses that signal the possibility of life, gasses such as oxygen, water vapor, methane, and carbon dioxide. And TPF will be capable of taking pictures that are one-hundred times more detailed than the photographs of the Hubble Space Telescope(哈勃太空望远镜).
Many astronomers are hopeful that these new telescopes will lead to a groundbreaking discovery of life elsewhere in the universe. Regardless of what discoveries they may yield, TPF and other space telescopes in development promise to bring exciting changes to space exploration.
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