The same thing is to be understood of all bodies, revolved in any orbits. They all endeavour to recede from the centres of their orbits, and were it not for the opposition of a contrary force which restrains them to and detains them in their orbits, which I therefore call Centripetal, would fly off in right lines with a uniform motion.

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

Philosophers have not kept up with modern developments in science. Particularly physics.

It may be that there is no such thing as an equable motion, whereby time may be accurately measured. All motions may be accelerated or retarded, but the true, or equable, progress of absolute time is liable to no change.

Resistance is usually ascribed to bodies at rest, and impulse to those in motion, but motion and rest, as commonly conceived, are only relatively distinguished; nor are those bodies always truly at rest, which commonly are taken to be so.

The observer, when he seems to himself to be observing a stone, is really, if physics is to be believed, observing the effects of the stone upon himself.

Quarks came in a number of varieties – in fact, at first, only three were needed to explain all the hundreds of particles and the different kinds of quarks – they are called u-type, d-type, s-type.

I went to Princeton specifically to study physics.

Painting is concerned with all the 10 attributes of sight; which are: Darkness, Light, Solidity and Colour, Form and Position, Distance and Propinquity, Motion and Rest.

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.

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.

Among physicists, I’m respected I hope.

OK, so what’s the speed of dark?

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

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

This most beautiful system of the sun, planets, and comets, could only proceed from the counsel and dominion of an intelligent and powerful Being.

Gravity must be caused by an Agent acting constantly according to certain laws, but whether this Agent be material or immaterial I have left to the consideration of my readers.

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

The motions of the comets are exceedingly regular, and they observe the same laws as the motions of the planets, but they differ from the motions of vortices in every particular and are often contrary to them.

From the point of view of basic physics, the most interesting phenomena are, of course, in the new places, the places where the rules do not work – not the places where they do work! That is the way in which we discover new rules.

I have explained the phenomena of the heavens and of our sea by the force of gravity, but I have not yet assigned a cause to gravity.

In my school, the brightest boys did math and physics, the less bright did physics and chemistry, and the least bright did biology. I wanted to do math and physics, but my father made me do chemistry because he thought there would be no jobs for mathematicians.

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.

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.

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.

I am not enough of a mathematician to be able to judge either the well-foundedness or the limits of relativity in physics.

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

In order to arrive at knowledge of the motions of birds in the air, it is first necessary to acquire knowledge of the winds, which we will prove by the motions of water in itself, and this knowledge will be a step enabling us to arrive at the knowledge of beings that fly between the air and the wind.

Atoms are very special: they like certain particular partners, certain particular directions, and so on. It is the job of physics to analyze why each one wants what it wants.

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.

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.

The moon and other celestial bodies should be free for exploration and use by all countries. No country should be permitted to advance a claim of sovereignty.

I need physics more than friends.

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.

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.

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.

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.

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.

Nature is ever at work building and pulling down, creating and destroying, keeping everything whirling and flowing, allowing no rest but in rhythmical motion, chasing everything in endless song out of one beautiful form into another.

My discovery that black holes emit radiation raised serious problems of consistency with the rest of physics. I have now resolved these problems, but the answer turned out to be not what I expected.

The fundamental concept in social science is Power, in the same sense in which Energy is the fundamental concept in physics.

The sun, with all those planets revolving around it and dependent on it, can still ripen a bunch of grapes as if it had nothing else in the universe to do.

To practice five things under all circumstances constitutes perfect virtue; these five are gravity, generosity of soul, sincerity, earnestness, and kindness.

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.

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

What goes up must come down.

We are the product of quantum fluctuations in the very early universe.

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.

Theoretical physics is one of the few fields in which being disabled is no handicap – it is all in the mind.

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.

The smaller the planets are, they are, other things being equal, of so much the greater density; for so the powers of gravity on their several surfaces come nearer to equality. They are likewise, other things being equal, of the greater density, as they are nearer to the sun.

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.

The drawing teacher has this problem of communicating how to draw by osmosis and not by instruction, while the physics teacher has the problem of always teaching techniques, rather than the spirit, of how to go about solving physical problems.

Everything starts somewhere, although many physicists disagree.

The moon gravitates towards the earth and by the force of gravity is continually drawn off from a rectilinear motion and retained in its orbit.

In the past, there was active discrimination against women in science. That has now gone, and although there are residual effects, these are not enough to account for the small numbers of women, particularly in mathematics and physics.

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.

Physics is really figuring out how to discover new things that are counterintuitive, like quantum mechanics. It’s really counterintuitive.

You can’t blame gravity for falling in love.

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.

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.