So far as physics is concerned, time's arrow is a property of entropy alone.

For the truth of the conclusions of physical science, observation is the supreme Court of Appeal.

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

It is also a good rule not to put overmuch confidence in the observational results that are put forward until they are confirmed by theory.

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.

We are bits of stellar matter that got cold by accident, bits of a star gone wrong.

It is reasonable to hope that in the not too distant future we shall be competent to understand so simple a thing as a star.