Stephen Hawking

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational.

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

Not to leave planet Earth would be like castaways on a desert island not trying to escape...Sending humans to other planets ... will shape the future of the human race in ways we don't yet understand, and may determine whether we have any future at all.

My advice to other disabled people would be, concentrate on things your disability doesn't prevent you doing well, and don't regret the things it interferes with. Don't be disabled in spirit, as well as physically.

Before I lost my voice, it was slurred, so only those close to me could understand, but with the computer voice, I found I could give popular lectures. I enjoy communicating science. It is important that the public understands basic science, if they are not to leave vital decisions to others.

If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans.

I don't care much for equations myself. This is partly because it is difficult for me to write them down, but mainly because I don't have an intuitive feeling for equations.

I was not a good student. I did not spend much _x000D_ time at college; I was too busy enjoying myself.

Many people find the universe confusing - it's not.

A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.

I hope I have helped to raise the profile of science and to show that physics is not a mystery but can be understood by ordinary people.

Please join me in applauding the ESA - European Space Agency’s historic efforts with the Rosetta Mission and landing a spacecraft on rotating comet. It may seem like a work of fiction, but it is very real, very impressive, and will help us to further uncover the mysteries surrounding the formation of the solar system. They made a beautiful short film using an imaginary landscape to illustrate today’s historic feat.

The missing link in cosmology is the nature of dark matter and dark energy.

I believe there are no questions that science can't answer about a physical universe.

We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.

Sometimes I wonder if I'm as famous for my wheelchair and disabilities as I am for my discoveries.

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.

According to 'M' theory, ours is not the only universe. Instead, 'M' theory predicts that a great many universes were created out of nothing.

We only have to look at ourselves to see how intelligent life might develop into something we wouldnt want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach.

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory.

I have found far greater enthusiasm for science in America than here in Britain. There is more enthusiasm for everything in America.