extra-, 外面的，超过的。terrestrial, 陆地的，地球的。即地球之外的，外星人。

1. NASA has started a 10-year search for extraterrestrial intelligence.

美国航空航天局已经启动了一个为期10年的寻找外星人的项目。

2. One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites.

地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的.

3. Discovering just one extraterrestrial civilization would have profound significance.

仅仅发现一个地外文明世界就会具有很深的意义.

4. Methane may have extraterrestrial significance.

甲烷具有星际意义.

5. In going through the earth's atmosphere the light from an extraterrestrial bodies suffers considerable absorption.

从地球以外的所有星体射来的光,在通过地球大气时,都会遭受很大的吸收.