| 释义 |
near-Earth asteroid
near-Earth asteroid N5046070 (nîr′ûrth′)n. Abbr. NEA An asteroid whose orbit around the sun brings it near Earth's orbit.near-Earth asteroid
near-Earth asteroid (NEA) Any asteroid that has a chance of hitting our planet, specifically any member of the Apollo, Amor, and Aten groups. Although the annual probability of the Earth being struck by a large asteroid or comet is extremely small, the consequences of such a collision are so catastrophic that it was thought prudent in the USA to assess the nature of the threat and to be prepared to deal with it.See NEA
See NEA |