Science can lift people out of poverty and cure disease. That, in turn, will reduce civil unrest.

There should be no boundaries to human endeavor. However bad life may seem, there is always hope.

In the last 200 years the population of our planet has grown exponentially, at a rate of 1.9% per year. If it continued at this rate, with the population doubling every 40 years, by 2600 we would all be standing literally shoulder to shoulder.

The fact that no one understands you doesn't mean you're an artist.

We see the universe the way it is because we exist.

So next time someone complains that you have made a mistake, tell him that may be a good thing. Because without imperfection, neither you nor I would exist.

I think the human race has no future if it doesn't go into space.