PRO TECTING EARTH:WHOSE JOB SIT?

摘要

This special issue of The Planetary Report exam-ines the threat of an impact by a near-Earthobject (NEO) on our planet and identifies thewidespread damage that could result. Although muchof the knowledge about this threat is relatively new, thedanger has always existed, as evidenced by the crateredhistory of the Earth and the Moon. Ignorance of thisdanger was blissful—at least until a catastrophe occurred.As we learn more about Earth's celestial neighborhood,we must cope not only with that knowledge but alsowith the uncertainties associated with it.