Quotes from Stephen Hawking

theory is a good theory if it satisfies two requirements. It must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.

In the Game of Life, as in our world, self-reproducing patterns are complex objects. One estimate, based on the earlier work of mathematician John von Neumann, places the minimum size of a self-replicating pattern in the Game of Life at ten trillion squares—roughly the number of molecules in a single human cell.

As a result, in more than three dimensions the sun would not be able to exist in a stable state with its internal pressure balancing the pull of gravity. It would either fall apart or collapse to form a black hole, either of which could ruin your day.

If you think it is hard to get humans to follow traffic laws, imagine convincing an asteroid to move along an ellipse.

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.

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.

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." Instead, he said that time was a property of the universe that God created, and that time did not exist before the beginning of the universe.

Because gravity shapes space and time, it allows space time to be locally stable but globally unstable. On the scale of the entire universe, the positive energy of the matter can be balanced by the negative gravitational energy, and so there is no restriction on the creation of whole universes. Because there is a law like gravity, the universe can and will create itself from nothing in the manner described in Chapter 6.

Real gravitons make up what classical physicists would call gravitational waves, which are very weak—and so difficult to detect that they have not yet been observed. The

the North Pole, but to someone looking from the equator, it appears to lie just at the horizon. From the difference in the apparent position of the North Star in Egypt and Greece, Aristotle even quoted an estimate that the distance

The Greeks even had a third argument that the earth must be round, for why else does one first see the sails of a ship coming over the horizon, and only later see the hull?

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?

La capacidad humana para sentirse culpable es tal que siempre podemos hallar maneras de acusarnos a nosotros mismos.

Newton's time it was possible for an educated person to have a grasp of the whole of human knowledge, at least in outline. But since then, the pace of the development of science has made this impossible.

As we shall see, the concept of time has no meaning before the beginning of the universe.

Eternity is a very long time, especially towards the end.

the physicist John Wheeler once calculated that if one took all the heavy water in all the oceans of the world, one could build a hydrogen bomb that would compress matter at the center so much that a black hole would be created. (Of course, there would be no one left to observe it!)

A proton or neutron is made up of three quarks, one of each color. A proton contains two up quarks and one down quark; a neutron contains two down and one up.

for the fluctuations in the background. However, within a few years we should know whether we can believe that we live in a universe that is completely self-contained and without beginning or end.

I have taken the opportunity to update the book and include new theoretical and observational results obtained since the book was first published (on April Fools' Day, 1988).

Now, if you believe that the universe is not arbitrary, but is governed by definite laws, you ultimately have to combine the partial theories into a complete unified theory that will describe everything in the universe. But there is a fundamental paradox in the search for such a complete unified theory.

The universe is a machine governed by principles or laws – laws that can be understood by the human mind.

There was a young lady of Wight Who travelled much faster than light She departed one day In a relative way And arrived on the previous night.

accuracy. The sun and the moon might still be gods, but they were gods who obeyed strict laws, apparently without any exceptions, if one discounts stories like that of the sun stopping for Joshua.