The big questions which occupy Hawking are:
- Where did we come from?
- How did the universe come into being?
- Are we alone in the universe?
- Is there alien life out there?
- What is the future of the human race?
Until the 1920’s we thought the universe was essentially static. But we found out that the universe has been expanding, and in fact we must have been all very close together at the beginning of time – about 15 billion years ago. The big bang, the start of the universe. Since then we’ve constantly kept moving outwards.
But was there anything before the big bang? Until recently we have had no information about the initial conditions of the universe. Now we know more about the start, and are starting to understand how it began.
We believe that life emerged spontaneously on earth, so it must be possible that life is on other planets, of which there is a large number in the galaxy. But we don’t know how life first appeared. We have fossils of algae from 3.5 billion years ago, the earth was formed about 4.6 billion years ago, and was probably too hot for the first half billion years. So life appeared within half a billion years of it being possible, which is short compared to the 10 billion year lifetime of a planet of earth type. So it seems probable that life can emerge relatively quickly, otherwise we would have expected it to take most of the 10 billion years available.
It seems unlikely that any aliens exist in our near field in the galaxy, since we’ve been searching hard with the SETI institute. If we are the only intelligent beings in the galaxy, then it seems even more important that we strive to stay around.
But we’re entering an increasingly dangerous period of our history. Our population and our use of the finite resources on earth are growing exponentially, along with our technical ability to change the environment for good or for ill.
Our only chance of long term survival is not to remain inward looking on planet earth, but to spread out into space.
The answers to the questions at the top show that we have made incredible progress in the past 100 years, but if we want to continue into the next 100, our future is in space.
Hawking says his disability has probably given him more time than most to pursue the quest for knowledge.
(Part of TED a day for June)