Jupiter is more than three hundred times biggerthan Earth,

木星比地球大300多倍

so it has a massive gravitational field.

所以它具有巨大的万有引力

This attracts dangerous flying objects that mightotherwise hit Earth.

这会吸引危险的飞行星体否则就会向地球飞来

Jupiter is Earth s protector.Scientists have even seen it in action.

木星是地球的保护神 科学家甚至亲眼见到过

In the early 1990s,a comet was captured by Jupiter's powerful gravity.

在20世纪90年代初 一个彗星被土星巨大的引力捕捉到

It broke up into many different pieces,which smashed into the planet.

它碎成了许多片 撞到了土星上

Some of the blasts left scars as big as Earth itself

有些爆炸留下的痕迹和地球一样大

Without Jupiter, it's likely Earth would have been pummelled

没有土星，地球可能会每隔一万年

by huge impacts like this e very 10,000 years or so.

就受到一次这样的冲击

Under that kind of bombardment,it's hard to imagine how complex life could ever have gotgoing.

在这样的轰炸下 很难想象复杂生命可以延续

Any planet that's to be a home to complex life needs liquid water,

任何星球想产生复杂生命都需要液态水

a sun that doesn't burn out too quickly and a giant neighbour to protect it from meteorites.

太阳不会很快蒸发它 有个巨大的邻居保护它不受陨石侵袭