Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.

I ask you to look both ways. For the road to a knowledge of the stars leads through the atom; and important knowledge of the atom has been reached through the stars.

Electrical force is defined as something which causes motion of electrical charge; an electrical charge is something which exerts electric force.

But it is necessary to insist more strongly than usual that what I am putting before you is a model-the Bohr model atom-because later I shall take you to a profounder level of representation in which the electron instead of being confined to a particular locality is distributed in a sort of probability haze all over the atom.

I am aware that many critics consider the conditions in the stars not sufficiently extreme . . . the stars are not hot enough. The critics lay themselves open to an obvious retort: we tell them to go and find a hotter place.

It is a primitive form of thought that things exist or do not exist.

The pursuit of truth in science transcends national boundaries. It takes us beyond hatred and anger and fear. It is the best of us.