Quotes About Theory

one of the twins went for a long trip in a spaceship at nearly the speed of light. When he returned, he would be much younger than the one who stayed on earth. This is known as the twins paradox, but it is a paradox only if one has the idea of absolute time at the back of one's mind. In the theory of relativity there is no unique absolute time, but instead each individual has his own personal measure of time that depends on where he is and how he is moving.

In 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. Because theories are always being changed to account for new observations, they are never properly digested or simplified so that ordinary people can understand them... Further, the rate of progress is so rapid that what one learns at school or university is always a bit out of date.

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.

famous equation, E = mc2. So, if there's

In the classical theory of gravity, which is based on real space-time, there are only two possible ways the universe can behave: either it has existed for an infinite time, or else it had a beginning at a singularity at some finite time in the past.

Why does the universe go to all the bother of existing? Is the unified theory so compelling that it brings about its own existence? Or does it need a creator, and, if so, does he have any other effect on the universe? And who created him?

Any physical theory is always provisional, in the sense that it is only a hypothesis: 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. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory.

Roger Penrose and I showed that Einstein's general theory of relativity implied that the universe must have a beginning and, possibly, an end.

It also predicted that the electron should have a partner: an antielectron, or positron. The discovery of the positron in 1932 confirmed Dirac's theory and led to his being awarded the Nobel prize for physics in 1933.

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!

a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation.

In other words, the theory of relativity put an end to the idea of absolute time!

Parece que en la naturaleza hay un cierto nivel de aleatoriedad o incertidumbre, que no se puede eliminar por muy buenas que sean las teorías. Eso se puede resumir en el Principio de Incertidumbre, formulado en 1927 por el científico alemán Werner Heisenberg.

In fact, according to quantum physics, each particle has some probability of being found anywhere in the universe.

If we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason—for then we would know the mind of God.

What most of these authors don't seem to have realized is that if you can travel faster than light, the theory of relativity implies you can also travel back in time, as the following limerick says: 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.

a scientific theory is just a mathematical model we make to describe our observations: it exists only in our minds. So it is meaningless to ask: which is real, real or imaginary time? It is simply a matter of which is the more useful description.

The eventual goal of science is to provide a single theory that describes the whole universe

Sin embargo, si descubrimos una teoría completa, debería en su momento ser comprensible en sus líneas generales por todos, no solo por unos pocos científicos. Entonces todos seremos capaces de tomar parte en la discusión de por qué el universo existe. Si encontramos la respuesta a ello, sería el triunfo definitivo de la razón humana, pues entonces conoceríamos la mente de Dios.

The fundamental postulate of the theory of relativity, as it was called, was that the laws of science should be the same for all freely moving observers, no matter what their speed.

Thus the possibility of time travel remains open.

There is no picture- or theory-independent concept of reality.

Yet if there really is a complete unified theory, it would also presumably determine our actions. And so the theory itself would determine the outcome of our search for it!

time and space are intertwined. It is something like adding a fourth direction of future/past to the usual left/right, forward/backward, and up/down. Physicists call this marriage of space and time "space-time," and because space-time includes a fourth direction, they call it the fourth dimension.