精选优质文档-倾情为你奉上1.Until the very latest moment of his existence, man has been bound to the planet on which he originated and developed. Now he had the capability to leave that planet S1._ and move out into the universe to those worlds which he has known previously only directly. Men have explored S2._ parts of the moon, put spaceships in orbit around another planet and possibly within the decade will land into another S3._ planet and explore it. Can we be to