The bad news is that forecasting asteroid impacts remains a tricky business.

坏消息是预测小行星撞击不是件容易事。

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Astronomers have yet to witness an asteroid impacts with another planet.

天文学家还没有目击过小行星撞击其它行星。

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Once the sun and planets took shape, heat became readily available in the form of solar radiation, asteroid impacts, and gravitational pressure.

太阳和行星成形后，太阳辐射、小行星撞击以及重力压力继续提供着热量。

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NASA's charter has also been changed explicitly to include a responsibility to provide advance warning of potentially damaging asteroid impacts.

ECONOMIST: The American Association for the Advancement of Science

Once the sun and planets took shape, heat became readily available in the form of solar radiation, asteroid impacts, and gravitational pressure.

ECONOMIST: Minerals

And long-term human settlement will follow at some point, mainly to develop mineral and energy resources available on the Moon, but also to emplace protective systems aimed at avoiding large asteroid impacts of the type we were all recently made aware with that grazing meteor strike in Chelyabinsk and the simultaneous near-miss by big-rock DA14.

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