Stephen Hawking Quotes

We have this interesting problem with black holes. What is a black hole? It is a region of space where you have mass that's confined to zero volume, which means that the density is infinitely large, which means we have no way of describing, really, what a black hole is!

Gravitational waves will bring us exquisitely accurate maps of black holes - maps of their space-time. Those maps will make it crystal clear whether or not what we're dealing with are black holes as described by general relativity.

A big misconception is that a black hole is made of matter that has just been compacted to a very small size. That's not true. A black hole is made from warped space and time.

Wormholes are a gravitational phenomena. Or imaginary gravitational phenomena, as the case may be.

It's not completely obvious what gravity is, fundamentally, or what dimensions are, fundamentally. One of these days we'll understand better what we mean, what is the fundamental thing that's given us space in the first place and dimensions of space in particular.

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

Einstein's gravitational theory, which is said to be the greatest single achievement of theoretical physics, resulted in beautiful relations connecting gravitational phenomena with the geometry of space; this was an exciting idea.

I always found it satisfying that gravity was described by Einstein's geometric theory of general relativity.

The black holes of nature are the most perfect macroscopic objects there are in the universe: the only elements in their construction are our concepts of space and time.

General relativity predicts that time ends inside black holes because the gravitational collapse squeezes matter to infinite density.

Black holes are very exotic objects. Technically, a black hole puts a huge amount of mass inside of zero volume. So our understanding of the center of black holes doesn't make sense, which is a big clue to physicists that we don't have our physics quite right.

General relativity is the cornerstone of cosmology and astrophysics. It has also provided the conceptual basis for string theory and other attempts to unify all the forces of nature in terms of geometrical structures.

We're going to need a definitive quantum theory of gravity, which is part of a grand unified theory - it's the main missing piece.

If space is a fabric, then of course fabrics can have ripples, which we have now seen directly. But fabrics can also rip. Then the question is what happens when the fabric of space and time is ripped by a black hole?

The quest for a quantum gravity is one of the greatest unsolved problems in all of science.

My work on black holes was on the connection between black holes and elementary particles.

The whole idea of gravity curling up space, that is the epitome of what is going on in a black hole. I would've loved to have seen Einstein's face if he were presented with the data that we actually discovered such a thing, because he himself probably didn't believe in much of it.

In real time, the universe has a beginning and an end at singularities that form a boundary to space-time and at which the laws of science break down.

Combining quantum entanglement with wormholes yields mind boggling results about black holes. But I don't trust them until we have a theory of everything which can combine quantum effects with general relativity. i.e. we need to have a full blown string theory resolve this sticky question.

In some sense, gravity does not exist; what moves the planets and the stars is the distortion of space and time.

When you fall into a black hole you will be literally spaghettified.

An event horizon, or the point of no return, is only a byproduct of the bending of space. However, electricity and magnetism, by themselves, have no event horizon. It gets complicated, however, if a black hole has charge, and then this new solution does have an event horizon.

Einstein comes along and says, space and time can warp and curve, that's what gravity is. Now string theory comes along and says, yes, gravity, quantum mechanics, electromagnetism - all together in one package, but only if the universe has more dimensions than the ones that we see.

When forced to summarize the general theory of relativity in one sentence: Time and space and gravitation have no separate existence from matter.

In curved Einsteinian space we are at all times, technically, looking at the back of our own head.