The fastest manned vehicle in history was Apollo 10. It reached 25,000 mph.

Intelligence is the ability to adapt to change.

I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth.

As Irving Good realised in 1965, machines with superhuman intelligence could repeatedly improve their design even further, triggering what Vernor Vinge called a 'singularity.'

It is not clear that intelligence has any long-term survival value.

We must develop as quickly as possible technologies that make possible a direct connection between brain and computer, so that artificial brains contribute to human intelligence rather than opposing it.

People won't have time for you if you are always angry or complaining.

I was not a good student. I did not spend much time at college; I was too busy enjoying myself.

Even if it turns out that time travel is impossible, it is important that we understand why it is impossible.

A zero-gravity flight is a first step toward space travel.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I'm no better than anyone else at understanding what makes people tick, particularly women.

It was Einstein's dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein's day hadn't made enough progress in understanding the forces of nature for that to be a realistic goal.

I would like nuclear fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming.

The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to minus 271.3*C - not much good for defrosting the pizza, let alone cooking it.

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is to work out what aliens might actually be like.

It's time to commit to finding the answer, to search for life beyond Earth. Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.

Life would be tragic if it weren't funny.

I think we have a good chance of surviving long enough to colonize the solar system.

Work gives you meaning and purpose and life is empty without it.

A few years ago, the city council of Monza, Italy, barred pet owners from keeping goldfish in curved bowls... saying that it is cruel to keep a fish in a bowl with curved sides because, gazing out, the fish would have a distorted view of reality. But how do we know we have the true, undistorted picture of reality?

Among physicists, I'm respected I hope.

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

I don't think the human race will survive the next thousand years, unless we spread into space.

Perhaps one day I will go into space.

Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities... space and time not only affect but are also affected by everything that happens in the universe.

Time can behave like another direction in space under extreme conditions.

I have wanted to fly into space for many years, but never imagined it would really be feasible.

Keeping an active mind has been vital to my survival, as has been maintaining a sense of humor.

However difficult life may seem, there is always something you can do and succeed at.