Stephen Hawking

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

The doctor who diagnosed me with ALS, or motor neuron disease, told me that it would kill me in two or three years.

I believe everyone should have a broad picture of how the universe operates and our place in it. It is a basic human desire. And it also puts our worries in perspective.

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.

I think the human race doesn't have a future if it doesn't go into space.

It is extremely important to me to write for children.

You can't regulate every lab in the world.

What I'd really like to control is not machines, but people.

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

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

Science predicts that many different kinds of universe will be spontaneously created out of nothing. It is a matter of chance which we are in.

Obviously, because of my disability, I need assistance. But I have always tried to overcome the limitations of my condition and lead as full a life as possible. I have traveled the world, from the Antarctic to zero gravity.

I entered the health care debate in response to a statement in the United States press in summer 2009 which claimed the National Health Service in Great Britain would have killed me off, were I a British citizen. I felt compelled to make a statement to explain the error.

We are the product of quantum fluctuations in the very early universe.

For years, my early work with Roger Penrose seemed to be a disaster for science. It showed that the universe must have begun with a singularity, if Einstein's general theory of relativity is correct. That appeared to indicate that science could not predict how the universe would begin.

Science is not only a disciple of reason but, also, one of romance and passion.

Scientists have become the bearers of the torch of discovery in our quest for knowledge.

Science is beautiful when it makes simple explanations of phenomena or connections between different observations. Examples include the double helix in biology and the fundamental equations of physics.

I want to know why the universe exists, why there is something greater than nothing.

Nothing cannot exist forever.

My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.

There are grounds for cautious optimism that we may now be near the end ofthe search for the ultimate laws of nature.

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.

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 thing about smart people is that they seem like crazy people to dumb people.

There is no unique picture of reality.

It is a waste of time to be angry about my disability. One has to get on with life and I havent done badly. People wont have time for you if you are always angry or complaining.

There is no physical law precluding particles from being organised in ways that perform even more advanced computations than the arrangements of particles in human brains.

The universe is governed by science. But science tells us that we can't solve the equations, directly in the abstract.

Life would be tragic if it weren't funny.

We live in a bewildering world.

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

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 was never top of the class at school, but my classmates must have seen potential in me, because my nickname was 'Einstein.'

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.

Someone told me that each equation I included in the book would halve the sales.

The human race may be the only intelligent beings in the galaxy.

Cosmology is a rapidly advancing field.

Teamwork means never having to take all the blame yourself.

I am discounting reports of UFOs. Why would they appear only to cranks and weirdos?

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

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

I was born on January 8, 1942, exactly three hundred years after the death of Galileo. I estimate, however, that about two hundred thousand other babies were also born that day. I don't know whether any of them was later interested in astronomy.

Intelligence is the ability to adapt to change.

We are very, very small, but we are profoundly capable of very, very big things.

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.

We are all now connected by the Internet, like neurons in a giant brain.

I can't say that my disability has helped my work, but it has allowed me to concentrate on research without having to lecture or sit on boring committees.

I have a full and satisfying life. My work and my family are very important to me.

God not only plays dice, but also sometimes throws them where they cannot be seen.

I think those who have a terminal illness and are in great pain should have the right to choose to end their own life, and those that help them should be free from prosecution.

The increase of disorder or entropy with time is one example of what is called an arrow of time something that distinguishes the past from the future giving a direction to time.

Only black holes of very low mass would emit a significant amount of radiation.

Not only does God play dice but... he sometimes throws them where they cannot be seen.

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?

I have visited Japan several times and have always been shown wonderful hospitality.

Philosophers have not kept up with modern developments in science. Particularly physics.

Women. They are a complete mystery.

In less than a hundred years, we have found a new way to think of ourselves. From sitting at the center of the universe, we now find ourselves orbiting an average-sized sun, which is just one of millions of stars in our own Milky Way galaxy.

Some forms of motor neuron disease are genetically linked, but I have no indication that my kind is. No other member of my family has had it. But I would be in favour of abortion if there was a high risk.

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.

The more you learn, the more you know. The more you know, the more you forget. The more you forget, the less you know. So why bother to learn.

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.

It is no good getting furious if you get stuck. What I do is keep thinking about the problem but work on something else. Sometimes it is years before I see the way forward. In the case of information loss and black holes, it was 29 years.

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.

My discovery that black holes emit radiation raised serious problems of consistency with the rest of physics. I have now resolved these problems, but the answer turned out to be not what I expected.

If the rate of expansion one second after the Big Bang had been smaller by even one part in a hundred thousand million million, it would have recollapsed before it reached its present size. On the other hand, if it had been greater by a part in a million, the universe would have expanded too rapidly for stars and planets to form.

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.

There are no black holes in the sense of regimes from which light can't escape to infinity.

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.

Although September 11 was horrible, it didn't threaten the survival of the human race, like nuclear weapons do.

My first popular book, 'A Brief History of Time,' aroused a great deal of interest, but many found it difficult to understand.

I believe the universe is governed by the laws of science. The laws may have been decreed by God, but God does not intervene to break the laws.

All my adult life people have been helping me.

Using e-mail, I can communicate with scientists all over the world.

I have wondered about time all my life.

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

When one's expectations are reduced to zero, one really appreciates everything one does have.

Science is increasingly answering questions that used to be the province of religion.

The voice I use is a very old hardware speech synthesizer made in 1986. I keep it because I have not heard a voice I like better and because I have identified with it.

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

It's a pity that nobody has found an exploding black hole. If they had, I would have won a Nobel prize.

I have noticed even people who claim everything is predestined, and that we can do nothing to change it, look before they cross the road.

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.

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 usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?

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

Energy is a bit like money if you have a positive balance you can distribute it in various ways but according to the classical laws that were believed at the beginning of the century you werent allowed to be overdrawn.

I don't want to write an autobiography because I would become public property with no privacy left.

Wagner manages to convey emotion with music better than anyone, before or since.

If aliens ever visit us I think the outcome would be much as when Christopher Columbus first landed in America which didnt turn out very well for the Native Americans.

I enjoy all forms of music - pop, classical and opera.

Because there is a law such as gravity, the universe can and will create itself from nothing.

There is no heaven or afterlife for broken-down computers; that is a fairy story for people afraid of the dark.

Time and space are finite in extent, but they don't have any boundary or edge. They would be like the surface of the earth, but with two more dimensions.

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

One cannot really argue with a mathematical theorem.

There could be shadow galaxies, shadow stars, and even shadow people.

The media need superheroes in science just as in every sphere of life, but there is really a continuous range of abilities with no clear dividing line.

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