It's better to read first rate science fiction than second rate science-it's a lot more fun, and no more likely to be wrong.

The 'clean energy' challenge deserves a commitment akin to the Manhattan project or the Apollo moon landing.

God invented space so that not everything had to happen in Princeton.

In the beginning there were only probabilities. The universe could only come into existence if someone observed it. It does not matter that the observers turned up several billion years later. The universe exists because we are aware of it.

It used to be controversial whether smoking caused lung cancer, it used to be controversial whether HIV caused AIDS. Now, there are a few mavericks who deny those things. In the case of climate change, I think the debate is going the same way in that there is a strong consensus that it is a serious matter.

All space projects push the frontiers of technology and are drivers of innovation.

I think all countries need to aim to cut the CO2 emissions per person, taking account of externalities like imports and exports.