My reluctance to use alien invasion is due to the feeling that we are not likely to be invaded and taken over.

This is written in the elder days as the Earth rides close to the rim of eternity, edging nearer to the dying Sun, into which her two inner companions of the solar system have already plunged to a fiery death. The Twilight of the Gods is history; and our planet drifts on and on into that oblivion from which nothing escapes, to which time itself may be dedicated in the final cosmic reckoning.

Before Man goes to the stars he should learn how to live on Earth .

Time is still the great mystery to us. It is no more than a concept; we don't know if it even exists.

I'm just a propagandist and a propagandist doesn't have to know what he is talking about, just so he talks about it most convincingly.

We came into a homeless frontier, a place where we were not welcome, where nothing that lived was welcome, where thought and logic were abhorrent and we were frightened, but we went into this place because the universe lay before us, and if we were to know ourselves, we must know the universe

We said, there's another second gone, there's another minute and another hour and another day, when, as a matter of fact the second or the minute or the hour was never gone. It was the same one all the time. It had just moved along and we had moved with it.