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Jupiter both protects and endangers us

点击量:   时间:2017-05-14 03:02:12

Is Jupiter a friend or foe? A bit of both, say astronomers who have analysed the giant planet’s influence on dangerous asteroids heading for Earth. The majority of near-Earth objects (NEOs) that threaten the Earth come from the asteroid belt between Mars and Jupiter, and from so-called centaurs, comets which orbit between Jupiter and Neptune. Jupiter is more than 300 times as massive as the Earth, and many believed the giant planet’s huge gravity helped protect the Earth from would-be NEOs by deflecting them away from us. To test this idea,