| 更新时间：2008/7/5 | ||
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» Download Audio By Jessica Berman Washington 04 July 2008 Data from the first flyby of the planet Mercury in January of 2008 by the spacecraft MESSENGER are reported in eleven papers this week in the journal Science. The findings reveal new details about the solar system's smallest planet 77 million kilometers from Earth. VOA's Jessica Berman reports.
Among the findings - Mercury's surface is made of smooth planes produced by lava flows and explosive eruptions billions of years ago. Scientists say the volcanic activity is responsible for huge craters on the surface similar to those on the Moon and Mars. Jim Head is a planetary geologist at Brown University in Rhode Island and lead author of one of the studies. Head says astronomers are interested in studying Mercury, the planet closest to the Sun, because so little is known about the formation of Earth, which is very young compared to Mercury. "Now that we have evidence for volcanism, we're starting to find a rich planetary example of these transitions between the early history of the planets and the later history that we observe on the Earth," said Jim Head. "So, from that sense, Mercury with these new data, and what we'll see as we have two more encounters and go into orbit, is really going to take its place in filling the pictures to those early chapters of the early solar system. And they are totally relevant to what the conditions were on the Earth that led to where we are today." The space probe will make two more flybys, one more in October of this year and at the end of September 2009, before settling into permanent orbit around Mercury in 2011. |
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