Imaginary time is a new dimension, at right angles to ordinary, real time.

If a projectile were deprived of the force of gravity, it would not be deflected toward the earth but would go off in a straight line into the heavens and do so with uniform motion, provided that the resistance of the air were removed.

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.

M-theory is the unified theory Einstein was hoping to find.

Theoretical physics is one of the few fields in which being disabled is no handicap – it is all in the mind.

Our minds work in real time, which begins at the Big Bang and will end, if there is a Big Crunch – which seems unlikely, now, from the latest data showing accelerating expansion. Consciousness would come to an end at a singularity.

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.

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 the product of quantum fluctuations in the very early universe.

All the evidence, experimental and even a little theoretical, seems to indicate that it is the energy content which is involved in gravitation, and therefore, since matter and antimatter both represent positive energies, gravitation makes no distinction.

Most people don’t have time to master the very mathematical details of theoretical physics.

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

Although almost every theoretical physicist agrees with my prediction that a black hole should glow like a hot body, it would be very difficult to verify experimentally because the temperature of a macroscopic black hole is so low.

Some scientists think it may be possible to capture a wormhole and enlarge it many trillions of times to make it big enough for a human or even a spaceship to enter.

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?

Mediocre theoretical physicists make no progress. They spend all their time understanding other people’s progress.

The cyclic universe theory predicts no gravitational waves from the early universe.

It now appears that the way the universe began can indeed be determined, using imaginary time.

It is theoretically possible to warp spacetime itself, so you’re not actually moving faster than the speed of light, but it’s actually space that’s moving.