Quotes from Stephen Hawking

Let us fight for every woman and every man to have the opportunity to live healthy, secure lives, full of opportunity and love. We are all time travellers, journeying together into the future. But let us work together to make that future a place we want to visit. Be brave, be curious, be determined, overcome the odds. It can be done.

can God make a stone so heavy that he can't lift it?

black holes are not really black after all: they glow like a hot body, and the smaller they are, the more they glow.

Quantum physics tells us that no matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities. The universe, according to quantum physics, has no single past, or history. The fact that the past takes no definite form means that observations you make on a system in the present affect its past.

If we find the answer to that (why the universe exists), it would be the ultimate triumph of human reason. For then we would know the mind of God.

So look carefully at the map of the microwave sky. It is the blueprint for all the structure in the universe. We are the product of quantum fluctuations in the very early universe. If one were religious, one could say that God really does play dice.

Yet if there really were a complete unified theory, it would also presumably determine our actions—so the theory itself would determine the outcome of our search for it! And why should it determine that we come to the right conclusions from the evidence? Might it not equally well determine that we draw the wrong conclusion? Or no conclusion at all?

Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?

an elipse is an elongated circle

Another prediction of general relativity is that time should appear to run slower near a massive body like the earth.

Black holes might be useful for getting rid of garbage or even some of one's friends.

A scientific law is not a scientific law, if it holds only when some supernatural being decides not to intervene

one has a singularity contained within a region of space-time known as a black hole.

Everyone can enjoy a life of luxurious leisure if the machine-produced [robots] wealth is shared, or most people can end up miserably poor if the machine-owners successfully lobby against wealth redistribution. So far, the trend seems to be toward the second option, with technology driving ever-increasing inequality.

As we shall see, the concept of time has no meaning before the beginning of the universe. This was first pointed out by St. Augustine. When asked: "What did God do before he created the universe?" Augustine didn't reply: "He was preparing Hell for people who asked such questions.

Consider the apparent dimension of the universe. According to M-theory, space-time has ten space dimensions and one time dimension. The idea is that seven of the space dimensions are curled up so small that we don't notice them, leaving us with the illusion that all that exist are the three remaining large dimensions we are familiar with.

String theory is rather like plumbing, in a way.

Heisenberg's uncertainty principle is a fundamental, inescapable property of the world. The

No boundary condition: The idea that the universe is finite but has no boundary (in imaginary time).

If there were events earlier than this time, then they could not affect what happens at the present time. Their existence can be ignored because it would have no observational consequences.

Normally, the energy of the particle is still positive, but the gravitational field inside a black hole is so strong that even a real particle can have negative energy there. It is therefore possible, if a black hole is present, for the virtual particle with negative energy to fall into the black hole and become a real particle or antiparticle.

An expanding universe does not preclude a creator, but it does place limits on when he might have carried out his job.

You can't get to a time before the Big Bang because there was no time before the Big Bang. We have finally found something that doesn't have a cause, because there was no time for a cause to exist in. For me this means that there is no possibility of a creator, because there is no time for a creator to have existed in.

Descartes, for instance, in order to preserve the idea of free will, asserted that the human mind was something different from the physical world and did not follow its laws. In his view a person consists of two ingredients, a body and a soul. Bodies are nothing but ordinary machines, but the soul is not subject to scientific law.