Quotes About Physics

But a machine that was powerful enough to accelerate particles to the grand unification energy would have to be as big as the Solar System—and would be unlikely to be funded in the present economic climate.

even if there were events before the big bang, one could not use them to determine what would happen afterward, because predictability would break down at the big bang.

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.

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

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.

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.

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

Anything or anyone who falls through the event horizon will soon reach the region of infinite density and the end of time.

Up to about thirty years ago, it was thought that protons and neutrons were "elementary" particles, but experiments in which protons were collided with other protons or electrons at high speeds indicated that they were in fact made up of smaller particles.

Jika Bumi berhenti berputar, maka menurut hukum Newton benda apapun yang tak terikat ke Bumi bakal terus bergerak dengan kecepatan perputaran Bumi (1100 mil per jam atau 1770 km per jam di khatulistiwa)

A scientific law is not a scientific law if it only holds when some supernatural being decides to let things run and not intervene. In

Mass: The quantity of matter in a body; its inertia, or resistance to acceleration.

I have led an extraordinary life on this planet, while at the same time travelling across the universe by using my mind and the laws of physics. I have been to the furthest reaches of our galaxy, travelled into a black hole and gone back to the beginning of time.

Feynman once wrote, "I think I can safely say that nobody understands quantum mechanics.

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 meant that whenever a body is not acted on by any force, it will keep on moving in a straight line at the same speed.

Only light, or other waves that have no intrinsic mass, can move at the speed of light.

Why do we see only three space dimensions and one time dimension? The suggestion is that the other dimensions are curved up into a space of very small size, something like a million million million million millionth of an inch. This is so small that we just don't notice it: we see only one time dimension and three space dimensions, in which space-time is fairly flat.

In 1956 two American physicists, Tsung-Dao Lee and Chen Ning Yang, suggested that the weak force does not in fact obey the symmetry P.

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 mass of the sun curves space-time in such a way that although the earth follows a straight path in four-dimensional space-time, it appears to us to move along a circular orbit in three-dimensional space.

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.