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《BBC 彗星的故事》(The Comet's Tale)[TVRip]
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34次 收藏
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【类型】：科学
【集数】：共1集
【片长】：60分钟
【字幕】：外挂英文
【服务器】：S-files ED Server (218.16.123.213 端口：80)
【供源状况&分享时间】：供源全天24小时
【内容简介】：
彗星曾被很多古代文明看作神，把它当作带来生命或世界末日的预兆，不过对Isaac Newton来说彗星则是揭开引力之谜的钥匙。几百年后，一种新的航天任务能告诉我们彗星的组成，彗星的来源以及对地球惊人的影响。
行星和太空科学研究所的Monica Grady 教授和Simon Green博士将出席本片。
Although believed to be gods by many ancient civilisations, who saw them as bringers of life or harbingers of doom, to Isaac Newton they were the key to unlocking the secrets of gravity. Hundreds of years later, a new breed of space mission can show what comets are really made of, where they come from, and their surprising influence on events on Earth.
PSSRI comet experts Professor Monica Grady and Dr Simon Green appeared in the BBC documentary "A Comet's Tale" broadcast on BBC4 on the 25th of November. Comets are of fundamental importance in understanding the origin of the Solar System and have been the subject of PSSRI space and laboratory studies for many years.
Comets are small (a few to a few tens of km) bodies made up of ices (water and other volatiles) and dust (containing silicate and organic material), which formed 4.6 billion years ago in the Outer Solar System. The material, which may contain dust grains which pre-date the Solar System and give insights into the processes which formed them in outflows from dying stars, is kept in deep freeze until a comet passes close to the Sun. Its spectacular appearance in the night sky is likely to mark the final stages of its life as the ices are vaporised. The European Space Agency's Rosetta mission is due to observe this process as it follows comet Churyumov-Gerasimenko in its orbit from a rendezvous in May 2014 until after its closest approach to the Sun in August 2015. It will drop a lander, carrying PSSRI's Ptolemy experiment, to investigate the properties and composition of cometary ices for the first time. PSSRI scientists have been involved in cometary missions since Giotto flew past comet Halley in 1986. Sensors designed by the group detected the impacts of cometary dust grains on the NASA Stardust spacecraft as it flew close to comet Wild-2 in 2004. Particles captured at this encounter and returned to Earth in 2007 are being studied in PSSRI laboratories.
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