A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.
Stephen HawkingThe idea of 10 dimensions might sound exciting, but they would cause real problems if you forget where you parked your car.
Stephen HawkingBut a machine that was powerful enough to accelerate particles to the grand unification energy would have to be as big as the Solar System - and would be unlikely to be funded in the present economic climate.
Stephen HawkingLife on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global warming, nuclear war, a genetically engineered virus or other dangers. I think the human race has no future if it doesn't go into space. I therefore want to encourage public interest in space.
Stephen Hawking