Henri Poincare Quotes

Absolute space, that is to say, the mark to which it would be necessary to refer the earth to know whether it really moves, has no objective existence.... The two propositions: "The earth turns round" and "it is more convenient to suppose the earth turns round" have the same meaning; there is nothing more in the one than in the other.

Absolute space, in its own nature, without regard to anything external, remains always similar and immovable. Relative space is some movable dimension or measure of the absolute spaces, which our senses determine by its position to bodies, and which is vulgarly taken for immovable space.

Relativity challenges your basic intuitions that you've built up from everyday experience. It says your experience of time is not what you think it is, that time is malleable. Your experience of space is not what you think it is; it can stretch and shrink.

Either CS (coordinate system) could be used with equal justification. The two sentences: the sun is at rest and the earth moves, or the sun moves and the earth is at rest, would simply mean two different conventions concerning two different CS

Relativity theory forced the abandonment, in principle, of absolute space and absolute time.

There are no fixed points in space.

In my relativity theory I set up a clock at every point in space, but in reality I find it difficult to provide even one clock in my room.

The bottom line is that time travel is allowed by the laws of physics.

I wouldn't say that 'The Fabric of the Cosmos' is a book on cosmology. Cosmology certainly plays a big part, but the major theme is our ever-evolving understanding of space and time, and what it all means for our sense of reality.

The abstract analysis of the world by mathematics and physics rests on the concepts of space and time.

And it really began with Einstein. We attended his lectures. Now the theory of relativity remained - and still remains - only a theory. It has not been proven. But it suggested a completely different picture of the physical world.

If you are in a spaceship that is traveling at the speed of light, and you turn on the headlights, does anything happen?

When you're falling through space time has no meaning.

Relativity teaches us the connection between the different descriptions of one and the same reality.

Formerly, people thought that if matter disappeared from the universe, space and time would remain. Relativity declares that space and time would disappear with matter.

In curved Einsteinian space we are at all times, technically, looking at the back of our own head.

If you look at Einstein's equations and put in low speeds and low gravity, they become Newton's equations.

All motion is relative. Maybe it's you who've moved away by standing still.

It was Einstein who made the real trouble. He announced in 1905 that there was no such thing as absolute rest. After that there never was.

Einstein's space is no closer to reality than Van Gogh's sky . The glory of science is not in a truth more absolute than the truth of Bach or Tolstoy, but in the act of creation itself. The scientist's discoveries impose his own order on chaos, as the composer or painter imposes his; an order that always refers to limited aspects of reality, and is based on the observer's frame of reference, which differs from period to period as a Rembrant nude differs from a nude by Manet.

In the beginning God said, the four-dimensional divergence of an antisymmetric, second rank tensor equals zero, and there was light, and it was good. And on the seventh day he rested.

Speed is relative. You have to live it. You can't just jump into it. You have to live it all the time.

It is almost impossible to have a baseless snobbish opinion of the General Theory of Relativity.

The Universe consists of non-simultaneously apprehended events.

Any schoolboy could see that man as a force must be measured by motion, from a fixed point.