Quotes About Physics

It's the gravity that shapes the large scale structure of the universe, even though it is the weakest of four categories of forces.

My advice to any heartbroken young girl is to pay close attention to the study of theoretical physics. Because one day there may well be proof of multiple universes. It would not be beyond the realms of possibility that somewhere outside of our own universe lies another different universe. And in that universe, Zayn is still in One Direction.

Traditionally these are questions for philosophy, but philosophy is dead. Philosophy has not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge.

Or in other words, why does disorder increase in the same direction of time as that in which the universe expands?

The people who actually make the advances in theoretical physics don't think in these categories that the philosophers and the historians of science subsequently invent for them

The message of this lecture is that black holes ain't as black as they are painted. They are not the eternal prisons they were once though…things can get out of a black hole both on the outside and possibly to another universe. So if you feel you are in a black hole, don't give up – there's a way out.

I have sold more books on physics than Madonna has on sex.

Disorder increases with time because we measure time in the direction in which disorder increases.

Although quantum mechanics has been around for nearly 70 years, it is still not generally understood or appreciated, even by those that use it to do calculations.

Quantum physics might seem to undermine the idea that nature is governed by laws, but that is not the case. Instead it leads us to accept a new form of determinism: given the state of a system at some time, the laws of nature determine the probabilities of various futures and pasts rather than determining the future and past with certainty.

There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands!

The last chapter discussed why we see time go forward: why disorder increases and why we remember the past but not the future.

the entropy of an isolated system always increases, and that when two systems are joined together, the entropy of the combined system is greater than the sum of the entropies of the individual systems.

We now know that every particle has an antiparticle, with which it can annihilate. (In the case of the force-carrying particles, the antiparticles are the same as the particles themselves.) There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands! You would both vanish in a great flash of light.

black holes are not really black after all: they glow like a hot body, and the smaller they are, the more they glow.

Quantum physics tells us that no matter how thorough our observation of the present, the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities. The universe, according to quantum physics, has no single past, or history. The fact that the past takes no definite form means that observations you make on a system in the present affect its past.

Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?

Another prediction of general relativity is that time should appear to run slower near a massive body like the earth.

one has a singularity contained within a region of space-time known as a black hole.

Consider the apparent dimension of the universe. According to M-theory, space-time has ten space dimensions and one time dimension. The idea is that seven of the space dimensions are curled up so small that we don't notice them, leaving us with the illusion that all that exist are the three remaining large dimensions we are familiar with.

String theory is rather like plumbing, in a way.

Heisenberg's uncertainty principle is a fundamental, inescapable property of the world. The

No boundary condition: The idea that the universe is finite but has no boundary (in imaginary time).

As an object approaches the speed of light, its mass rises ever more quickly, so it takes more and more energy to speed it up further. It can in fact never reach the speed of light, because by then its mass would have become infinite, and by the equivalence of mass and energy, it would have taken an infinite amount of energy to get it there. For this reason, any normal object is forever confined by relativity to move at speeds slower than the speed of light.