Where we have strong emotions, we're liable to fool ourselves.

In more than one respect, the exploring of the Solar System and homesteading other worlds constitutes the beginning, much more than the end, of history.

Anything else you're interested in is not going to happen if you can't breathe the air and drink the water. Don't sit this one out. Do something. You are by accident of fate alive at an absolutely critical moment in the history of our planet.

Any civilization that doesn't develop space travel dies.

In a complex universe, in a society undergoing unprecedented change, how can we find the truth if we are not willing to question everything and to give a fair hearing to everything?

I would love to believe that when I die I will live again, that some thinking, feeling, remembering part of me will continue.

She had studied the universe all her life, but had overlooked its clearest message: For small creatures such as we the vastness is bearable only through love.