I have wondered about time all my life.
A zero-gravity flight is a first step toward space travel.
However difficult life may seem, there is always something you can do and succeed at.
There are no black holes in the sense of regimes from which light can't escape to infinity.
We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet.
It is extremely important to me to write for children.
'The Simpsons' appearances were great fun. But I don't take them too seriously. I think 'The Simpsons' have treated my disability responsibly.
Using e-mail, I can communicate with scientists all over the world.
The universe is not indifferent to our existence - it depends on it.
Science is increasingly answering questions that used to be the province of religion.
I can't disguise myself with a wig and dark glasses - the wheelchair gives me away.
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.
There is no unique picture of reality.
There is a real danger that computers will develop intelligence and take over. We urgently need to develop direct connections to the brain so that computers can add to human intelligence rather than be in opposition.
I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe.
Exploration by real people inspires us.
Success in creating AI would be the biggest event in human history. Unfortunately, it might also be the last, unless we learn how to avoid the risks.
I was never top of the class at school, but my classmates must have seen potential in me, because my nickname was 'Einstein.'
The Paralympic Games is about transforming our perception of the world.
So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simply be. What place, then, for a creator?
One can't predict the weather more than a few days in advance.
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.
My ideal role would be a baddie in a James Bond film. I think the wheelchair and the computer voice would fit the part.
Sometimes I wonder if I'm as famous for my wheelchair and disabilities as I am for my discoveries.
My father was a research scientist in tropical medicine, so I always assumed I would be a scientist, too. I felt that medicine was too vague and inexact, so I chose physics.
Philosophers have not kept up with modern developments in science. Particularly physics.
Evolution has ensured that our brains just aren't equipped to visualise 11 dimensions directly. However, from a purely mathematical point of view it's just as easy to think in 11 dimensions, as it is to think in three or four.
Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.
I wouldn't be here today if it were not for the NHS. I have received a large amount of high-quality treatment without which I would not have survived.