We seem, these days, much more willing to recognize the perils before us than we were even a decade ago. The newly recognized dangers threaten all of us, equally. No one can say how it will turn out down here. But this is also, we may note, the first time that a species has become able to journey to the planets and the stars. Sailors on a becalmed sea, we sense a stirring of the breeze.
Carl SaganEach of us is a tiny being, permitted to ride on the outermost skin of one of the smaller planets for a few dozen trips around the local star.
Carl SaganAt the extremes it is difficult to distinguish pseudoscience from rigid, doctrinaire religion.
Carl Sagan