A million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe.
Stephen HawkingIf it [the universe] was expanding fairly slowly, the force of gravity would cause it eventually to stop expanding and then to start contracting. However, if it was expanding at more than a certain critical rate, gravity would never be strong enough to stop it, and the universe would continue to expand forever.
Stephen HawkingBecause imaginary time behaves like another direction in space, histories in imaginary time can be closed surfaces, like the surface of the Earth, with no [existential] beginning or end.
Stephen Hawking