(On the energy radiated by the Sun) It's four hundred million million million million watts. That is a million times the power consumption of the United States every year, radiated in one second, and we worked that out by using some water, a thermometer, a tin, and an umbrella. And that's why I love physics.

Don't undermine the science just because you don't like the economics. That's a dangerous slope, because the problem of course is you're not undermining just that, you're undermining the basis of rational decision-making in society.

Look at that! If you ever needed convincing that we live in the solar system, that we are on a ball of rock, orbiting around the Sun with other balls of rock, then look at that! That's the solar system coming down and grabbing you by the throat.

When you fall into a black hole you will be literally spaghettified.

For the first time, we saw our world, not as a solid, immovable, kind of indestructible place, but as a very small, fragile-looking world just hanging against the blackness of space.

We explore because we are curious, not because we wish to develop grand views of reality or better widgets.

Deeper understanding confers that most precious thing - wonder.