I shot down two airplanes in Korea, so I wasn't a slouch.

The energy varies with the square of the velocity, so if you need five times the velocity, that's 25 times the energy.

When President Kennedy took office, I was in the midst of my education.

When we set out to land people on the surface of Mars, I think we should as a nation, as a world, commit ourselves to supporting a growing settlement and colonization there. To visit a few times and then withdraw would be an unforgivable waste of resources.

I understand that Detroit was a pretty rough place to grow up in the '70s and '80s.

Don't waste your time on beaming people up or down. Instead, consider gravity waves as advanced physics of the universe that could be used to travel interstellar distances.

I want to reach a new generation. That's why I am Twittering now. I have a BlackBerry, an iPhone and a Mac.