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

There is so much left of it to explore.

Light is the only connection we have with the Universe beyond our solar system, and the only connection our ancestors had with anything beyond Earth. Follow the light and we can journey from the confines of our planet to other worlds that orbit the Sun without ever dreaming of spacecraft. To look up is to look back in time, because the ancient beams of light are messengers from the Universe's distant past.

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.

(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.

You dig deeper and it gets more and more complicated, and you get confused, and it's tricky and it's hard, but... It is beautiful.

Science is different to all other systems of thought because you dont need faith in it, you can check that it works.