There are three reasons, . . . apart from scientific considerations, mankind needs to travel in space. The first . . . is garbage disposal; we need to transfer industrial processes into space so that the earth may remain a green and pleasant place for our grandchildren to live in. The second . . . to escape material impoverishment: the resources of this planet are finite, and we shall not forego forever the abundance of solar energy and minerals and living space that are spread out all around us. The third . . . our spiritual need for an open frontier.

To me, mathematics is like playing the violin. Some people can do it - others can't. If you don't have it, then there's no point in pretending.

People who travel in China tell me that the mood there is still very upbeat, because their media is different from our media. Chinese media emphasize how well things are going and suppress the bad news and publish the good news.

It has become part of the accepted wisdom to say that the twentieth century was the century of physics and the twenty-first century will be the century of biology.

Almost everything about the universe is astounding. I think the most amazing thing is how gifted we are - we are only monkeys who came down from the trees just recently. We have these amazing gifts of music and mathematics and painting and Olympic running.

The public knows that human beings are fallible. Only people blinded by ideology fall into the trap of believing in their own infallibility.

As far as I can see, our concentration of different abilities in one species - there's nothing I can see that in this Darwinian evolution that could've done that. So it seems to be a miracle of some sort.