This whole issue of limits to growth, which provides a psychological, as well as a physical, cap on potential expansion of activity and awareness, has had a very depressing effect on many people.... I don't for a moment think that there's any concept which anyone's working with now which will be followed as a straightforward scenario. But the idea embodied in concepts such as space colonization or space industrialization, or availability of nonterrestrial resources, is fundamental, and it will change the way in which people look at the future.

It is not enough to do a desktop exercise of a Beethoven symphony. You need to practice with an orchestra. The musicians need to read the notes. Otherwise it will be a disaster.

You almost wish you could turn off the COMM and just appreciate the deafening quiet.

We can both prevent asteroid impacts and address climate change. It's not either-or.

I am interested in climate change and other topics too. But this thing is so huge, in the worst case we are talking about the end of our civilization.

You see the Earth as a bright blue and white Christmas tree ornament in the black sky. It's so small and so fragile - you realize that on that small spot is everything that means everything to you; all of history and art and death and birth and love.

We not only need to train people, we also need to develop deflection technologies.