With the exception of gravitation and radioactivity, all of the phenomena known to physicists and chemists in 1911 have their ultimate explanation in the laws of quantum electrodynamics.

All the evidence, experimental and even a little theoretical, seems to indicate that it is the energy content which is involved in gravitation, and therefore, since matter and antimatter both represent positive energies, gravitation makes no distinction.

Here’s what I’ve learned about deal-breakers. If you have enough natural chemistry with someone, you overlook every single thing that you said would break the deal.

I think equation guessing might be the best method to proceed to obtain the laws for the part of physics which is presently unknown. Yet, when I was much younger, I tried this equation guessing, and I have seen many students try this, but it is very easy to go off in wildly incorrect and impossible directions.

I think we all change each other’s paths. I don’t know which law idea that is in physics, but I don’t think any of us can live without affecting one another.

Today, all physicists know from studying Einstein and Bohr that sometimes an idea which looks completely paradoxical at first, if analyzed to completion in all detail and in experimental situations, may, in fact, not be paradoxical.

There are no black holes in the sense of regimes from which light can’t escape to infinity.

The internal machinery of life, the chemistry of the parts, is something beautiful. And it turns out that all life is interconnected with all other life.

Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity.

An object in motion tends to remain in motion along a straight line unless acted upon by an outside force.

Most people have no concept of how an automatic transmission works, yet they know how to drive a car. You don’t have to study physics to understand the laws of motion to drive a car. You don’t have to understand any of this stuff to use Macintosh.

OK, so what’s the speed of dark?

My father was a research scientist in tropical medicine, so I always assumed I would be a scientist, too. I felt that medicine was too vague and inexact, so I chose physics.

Working out another system to replace Newton’s laws took a long time because phenomena at the atomic level were quite strange. One had to lose one’s common sense in order to perceive what was happening at the atomic level.

Just as the system of the sun, planets and comets is put in motion by the forces of gravity, and its parts persist in their motions, so the smaller systems of bodies also seem to be set in motion by other forces and their particles to be variously moved in relation to each other and, especially, by the electric force.

Obama has no way to conceal that Osama was executed in front of his children and wives, who are now under the custody of the authorities of Pakistan, a Muslim country of almost 200 million inhabitants, whose laws have been violated, its national dignity offended, and its religious traditions desecrated.

We get the exciting result that the total energy of the universe is zero. Why this should be so is one of the great mysteries – and therefore one of the important questions of physics. After all, what would be the use of studying physics if the mysteries were not the most important things to investigate?

It now appears that the way the universe began can indeed be determined, using imaginary time.

Good men must not obey the laws too well.

Because there is a law such as gravity, the universe can and will create itself from nothing.

I hope I have helped to raise the profile of science and to show that physics is not a mystery but can be understood by ordinary people.

Like Cato, give his little senate laws, and sit attentive to his own applause.

Because atomic behavior is so unlike ordinary experience, it is very difficult to get used to, and it appears peculiar and mysterious to everyone – both to the novice and to the experienced physicist.

Electrical science has disclosed to us the more intimate relation existing between widely different forces and phenomena and has thus led us to a more complete comprehension of Nature and its many manifestations to our senses.

Physics has a history of synthesizing many phenomena into a few theories.

My background educationally is physics and economics, and I grew up in sort of an engineering environment – my father is an electromechanical engineer. And so there were lots of engineery things around me.

M-theory is the unified theory Einstein was hoping to find.

There is no physical law precluding particles from being organised in ways that perform even more advanced computations than the arrangements of particles in human brains.

I tell you the solemn truth, that the doctrine of the Trinity is not so difficult to accept for a working proposition as any one of the axioms of physics.

There were several possible solutions of the difficulty of classical electrodynamics, any one of which might serve as a good starting point to the solution of the difficulties of quantum electrodynamics.

It is necessary for him who lays out a state and arranges laws for it to presuppose that all men are evil and that they are always going to act according to the wickedness of their spirits whenever they have free scope.

You have a row of dominoes set up; you knock over the first one, and what will happen to the last one is that it will go over very quickly.

In time of war the laws are silent.

Because the theory of quantum mechanics could explain all of chemistry and the various properties of substances, it was a tremendous success. But still there was the problem of the interaction of light and matter.

There happen to be a lot of people around who spent an hour on the Internet and think they know a lot of physics, but it doesn’t work like that… There’s a reason there are graduate schools in these departments.

Science has revealed that the human body is made up of millions and millions of atoms… For example, I am made up of 5.8×10 27 atoms.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I’m no better than anyone else at understanding what makes people tick, particularly women.

Each piece, or part, of the whole of nature is always merely an approximation to the complete truth, or the complete truth so far as we know it. In fact, everything we know is only some kind of approximation because we know that we do not know all the laws as yet.

Chemistry can be a good and bad thing. Chemistry is good when you make love with it. Chemistry is bad when you make crack with it.

I had a project for my life which involved 10 years of wandering, then some years of medical studies and, if any time was left, the great adventure of physics.

If a projectile were deprived of the force of gravity, it would not be deflected toward the earth but would go off in a straight line into the heavens and do so with uniform motion, provided that the resistance of the air were removed.

It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but, with a little mathematical fiddling, you can show the relationship.

Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities… space and time not only affect but are also affected by everything that happens in the universe.

When I was a young man, Dirac was my hero. He made a breakthrough, a new method of doing physics. He had the courage to simply guess at the form of an equation, the equation we now call the Dirac equation, and to try to interpret it afterwards.

I tend to approach things from a physics framework. And physics teaches you to reason from first principles rather than by analogy.

The first amazing fact about gravitation is that the ratio of inertial mass to gravitational mass is constant wherever we have checked it. The second amazing thing about gravitation is how weak it is.

There are children playing in the streets who could solve some of my top problems in physics, because they have modes of sensory perception that I lost long ago.

Science is beautiful when it makes simple explanations of phenomena or connections between different observations. Examples include the double helix in biology and the fundamental equations of physics.

I have no doubt but that the misery of the lower classes will be found to abate whenever the Government assumes a freer aspect and the laws favor a subdivision of Property.

The greatest progress is in the sciences that study the simplest systems. So take, say, physics – greatest progress there. But one of the reasons is that the physicists have an advantage that no other branch of sciences has. If something gets too complicated, they hand it to someone else.

I think you should always bear in mind that entropy is not on your side.

In some sort of crude sense, which no vulgarity, no humor, no overstatement can quite extinguish, the physicists have known sin; and this is a knowledge which they cannot lose.

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?

Chemistry, until my childhood, not that long ago, was regarded as a calculating device. Because you couldn’t reduce to physics. So it’s just some way of calculating the result of experiments. The Bohr atom was treated that way.

One of the peculiarities of Delhi is that the term ‚reform‘ is associated only with passing of laws in Parliament. In fact, the most important reforms are those needed, without new laws, at various level of the government, in work practices and procedures.

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

My first popular book, ‚A Brief History of Time,‘ aroused a great deal of interest, but many found it difficult to understand.

No one undertakes research in physics with the intention of winning a prize. It is the joy of discovering something no one knew before.

Time can behave like another direction in space under extreme conditions.

It is now quite lawful for a Catholic woman to avoid pregnancy by a resort to mathematics, though she is still forbidden to resort to physics or chemistry.

In experimental philosophy, we are to look upon propositions inferred by general induction from phenomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur by which they may either be made more accurate or liable to exceptions.