This required abandoning the idea that there is a universal quantity called time that all clocks measure. Instead, everyone would have his own personal time. The clocks of two people would agree if they were at rest with respect to each other but not if they were moving. This has been confirmed by a number of experiments, including one in which an extremely accurate timepiece was flown around the world and then compared with one that had stayed in place. If you wanted to live longer, you could keep flying to the east so the speed of the plane added to the earth
Stephen HawkingA million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe.
Stephen HawkingThink of our DNA. In the last million years, our DNA hasn't changed at all. It's really much the same as it was in the jungle, a million, two millions years ago. But in the last 200 years, our destructive capacities have increased many, many millions of times over. Why don't we see intelligent signals from outer space? Because in all likelihood, once the civilization reaches the point our civilization has reached, it destroys itself.
Stephen Hawking