金沙国际唯一指定官网

The ice planet

作者:公西踹镩    发布时间:2019-03-07 02:15:01    

By Henry Bortman MELTING glaciers rather than flowing surface water could have carved out the Red Planet’s distinctive valleys. Branching networks of small valleys have led many scientists to conclude that rivers of running water once flowed freely across the surface of Mars. But this would mean that the Red Planet once had a much warmer climate than it does today and, apart from its valleys, there is no evidence to suggest that Mars was ever warm (New Scientist, 17 April 1999, p 48). But Pascal Lee, a planetary scientist at NASA’s Ames Research Center in Mountain View, California,

 

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