The reason dogs have so many friends is because they wag their tails instead of their tongues.
Dogs look up to you. Cats look down on you. Give me a pig. He just looks you in the eye and treats you like an equal.
The most incomprehensible thing about the universe is that it is comprehensible.
A time will come when men will stretch out their eyes. They should see planets like our Earth.
Lie on your back and look at the stars.
The universe is like a safe to which there is a combination, but the combination is locked up in the safe.