A million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe.

The universe does not behave according to our pre-conceived ideas. It continues to surprise us.

Mankind's greatest achievements have come about by talking and its greatest failures by not talking. It doesn’t have to be like this.

Why do we remember the past, but not the future?

Religion believes in miracles, but these aren't compatible with science.

I don't believe that the ultimate theory will come by steady work along existing lines. We need something new. We can't predict what that will be or when we will find it because if we knew that, we would have found it already!

Over a very small number of rolls of the dice, the uncertainty principle is very important.