Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million. Our only chance of long term survival, is not to remain inward looking on planet Earth, but to spread out into space.

Observations indicate that the universe is expanding at an ever increasing rate. It will expand forever, getting emptier and darker.

Someone told me that each equation I included in the book would halve the sales.

Think 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.

In the last 200 years the population of our planet has grown exponentially, at a rate of 1.9% per year. If it continued at this rate, with the population doubling every 40 years, by 2600 we would all be standing literally shoulder to shoulder.

[On President Bush's plan to get to Mars in 10 years] Stupid. Robots would do a better job and be much cheaper because you don't have to bring them back.

What I meant by 'we would know the mind of God' is, we would know everything that God would know, if there were a God. Which there isn't. I'm an atheist.