A Brief History Of Time Quotes
"What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise."
"What is the nature of time? Will it ever come to an end? Can we go back in time?"
"The earth’s shadow on the moon was always round, which would be true only if the earth was spherical."
"If the earth had been a flat disk, the shadow would have been elongated and elliptical."
"The outermost sphere carried the so-called fixed stars."
"It was this same force that caused objects to fall to the ground."
"In an infinite universe, every point can be regarded as the center."
"This argument is an instance of the pitfalls that you can encounter in talking about infinity."
"The theory is a good theory if it satisfies two requirements."
"You can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory."
"A body of twice the weight will have twice the force of gravity pulling it down."
"The apparent brightness of a star depends on two factors: how much light it radiates, and how far it is from us."
"The universe must have had a beginning in time, until in 1970 this was finally proved."
"The uncertainty principle signaled an end to Laplace’s dream of a theory of science, a model of the universe that would be completely deterministic."
"One certainly cannot predict future events exactly if one cannot even measure the present state of the universe precisely!"
"We could still imagine that there is a set of laws that determine events completely for some supernatural being."
"It seems better to employ the principle of economy known as Occam’s razor and cut out all the features of the theory that cannot be observed."
"Quantum mechanics does not predict a single definite result for an observation."
"Einstein objected to this very strongly, despite the important role he had played in the development of these ideas."
"Einstein never accepted that the universe was governed by chance; his feelings were summed up in his famous statement 'God does not play dice.'"
"Quantum mechanics has been an outstandingly successful theory and underlies nearly all of modern science and technology."
"The theory of quantum mechanics is based on an entirely new type of mathematics."
"There is thus a duality between waves and particles in quantum mechanics."
"One such black hole could run ten large power stations, if only we could harness its power."
"If you had one of these black holes on the surface of the earth, there would be no way to stop it from falling through the floor to the center of the earth."
"We could look for the gamma rays that the primordial black holes emit during most of their lifetime."
"The existence of radiation from black holes seems to imply that gravitational collapse is not as final and irreversible as we once thought."
"The universe would be completely self-contained and not affected by anything outside itself. It would neither be created nor destroyed. It would just BE."
"A space-time in which events have imaginary values of the time coordinate is said to be Euclidean."
"This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases."
"The idea of wormholes between different regions of space-time was not an invention of science fiction writers but came from a very respectable source."
"The Einstein-Rosen bridges didn’t last long enough for a spaceship to get through."
"Energy is a bit like money: if you have a positive balance, you can distribute it in various ways."
"The quantum laws are more liberal and allow you to be overdrawn on one or two accounts."
"One might hope therefore that as we advance in science and technology, we would eventually manage to build a time machine."
"A possible way to explain the absence of visitors from the future would be to say that the past is fixed."
"The Feynman sum over histories does allow travel into the past on a microscopic scale."
"In string theory, what were previously thought of as particles are now pictured as waves."
"Quantum mechanics implies that certain pairs of quantities, such as the position and velocity of a particle, cannot both be predicted with complete accuracy."
"If the no boundary proposal is correct, [God] had no freedom at all to choose initial conditions."
"Why does the universe go to all the bother of existing? Is the unified theory so compelling that it brings about its own existence?"