Quotes About Physics

And it is at this point that an extraordinary idea occurred to him, a stroke of pure genius: the gravitational field is not diffused through space; the gravitational field is that space itself. This is the idea of the general theory of relativity. Newton's "space," through which things move, and the "gravitational field" are one and the same thing.

Empowered by new conceptual tools and by mathematics, Einstein writes the equations which describe Democritus's void and finds for its 'certain physics' a colourful and amazing world where universes explode, space collapses into bottomless holes, time slows down in the vicinity of a planet, and the boundless expanses of interstellar space ripple and sway like the surface of the sea

The difference between past and future only exists when there is heat. The fundamental phenomenon that distinguishes the future from the past is the fact that heat passes from things that are hotter to things that are colder.

quantum mechanics cannot deal with the curvature of spacetime, and general relativity cannot account for quanta. This is the problem of quantum gravity.

Heisenberg had understood that you can't locate a particle at a point in space for long: it soon escapes. The smaller the region where we try to locate a particle, the greater the velocity at which it escapes.

There is no preferred direction of time without heat.

La forza che tiene incollati i quarks all'interno dei protoni e dei neutroni è generata da particelle che i fisici, con poco senso del ridicolo, chiamano «gluoni», dall'inglese glue, colla. In italiano si tradurrebbe «colloni», ma fortunatamente usano tutti il nome inglese.

A calculation, in fact, demonstrates that without nodes, physical space has no volume. In other words, it is in the nodes of the graph, not in the lines, that the volume of space "resides." The lines "link together" individual volumes sitting at the nodes.

Let's begin with a simple fact: time passes faster in the mountains than it does at sea level.

Any description of a system is therefore always a description of the information a system has about another system, that is to say, the correlation between the two systems.

I want a theory of physics that accounts for the structure of the universe, that clarifies what it is to be an observer in the universe, not a theory that makes the universe depend on me observing it.

Every cubic centimeter of space, and every second that passes, is the result of this dancing foam of extremely small quanta.

Ten years before understanding that time is slowed down by mass,21 Einstein had realized that it was slowed down by speed.22 The consequence of this discovery for our basic intuitive perception of time is the most devastating of all.

Proper time" depends not only on where you are and your degree of proximity to masses; it depends also on the speed at which you move. It's a strange enough fact in itself, but its consequences are extraordinary. Hold on tight, because we are about to take

The idea that a well-defined now exists throughout the universe is an illusion, an illegitimate extrapolation of our own experience.

It is the curious local structure of the present that produces black holes.

the spatiotemporal entity of Einstein.

The sun bends space around itself, and Earth does not turn around it because of a mysterious force but because it is racing directly in a space that inclines, like a marble that rolls in a funnel. There are no mysterious forces generated at the center of the funnel; it is the curved nature of the walls that causes the marble to roll. Planets circle around the sun, and things fall, because space curves.

That is, there is no meaning to the velocity of an object by itself: the only velocity that exists is the velocity of an object with respect to another object.

Michele has left this strange world a little before me. This means nothing. People like us, who believe in physics, know that the distinction made between past, present and future is nothing more than a persistent, stubborn illusion.

is Entropy, not Energy, that Drives the World

The difference between past and future exists only when there is heat. The fundamental phenomenon that distinguishes the future from the past is the fact that heat passes from things

The present is a localized rather than a global phenomenon.

With a great deal of effort, seeking help from friends better versed in mathematics than himself, Einstein learns Riemann's math—and writes an equation where R is proportional to the energy of matter. In words: spacetime curves more where there is matter. That is it.