“Becoming a multi-planet species and spacefaring civilization — this is not inevitable — it’s very important to appreciate: this is not inevitable. The sustainable energy future I think is largely inevitable but becoming a spacefaring species is definitely not inevitable. If you look at the progress in space — in 1969 we were able to send somebody to the moon. Nineteen sixty-nine. Then we had the space shuttle. The space shuttle could only take people to low Earth orbit. Then the space shuttle retired and the United States could take no one to orbit. So that’s the trend. The trend is like [downward hand movement]…down to nothing. This is not — people are mistaken if they think that technology automatically improves. It does not automatically improve. It only automatically improves if a lot of people work very hard to make it better. And actually it will, I think, if left by itself degrade actually. If you look at civilizations like Ancient Egypt and they were able to make the pyramids, and they forgot how to do that. And the Romans, they built these incredible aqueducts. They forgot how to do it.”