SSS 2008-11-17(在线收听) |
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This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.
Science fiction is filled with stories of planets circling distant stars. Now astronomers have produced the first image of multiple planets circling a star that’s not our sun. The planets are five to thirteen times more massive than Jupiter. And their order by size mimics our own solar system. The discovery is in the November 14th issue of the journal Science. Astronomers faced a big challenge finding those planets: telescopes can’t just catch a planet in orbit. So a common method is to determine the planets’ gravitational pull on their home star. But that only works for planets whose orbit is relatively close to their sun. Newer procedures measure infrared radiation from recently formed planets. And a technique called adaptive optics is also used to create images of planets. It corrects for the fact that the glare of the home star makes nearby planets difficult to see. It was adaptive optics that made the new solar system visible to us. In other world news, a planet’s been found orbiting the star Fomalhaut, just 25 light-years from earth. Next year they’ll find out who gets elected President, Reagan or Mondale.
Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.
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原文地址:http://www.tingroom.com/lesson/sasss/2008/11/98934.html |