The world has changed far more in the past 100 years than in any other century in history. The reason is not political or economic but technological-technologies that flowed directly from advances in basic science. Clearly, no scientist better represents those advances than Albert Einstein: TIME's Person of the Century.

People won't have time for you if you are always angry or complaining.

Science can explain the universe without the need for a Creator.

I think the universe was spontaneously created out of nothing, according to the laws of science. It has no beginning and no end.

The real challenge is to work out what aliens might actually be like.

We find ourselves in a bewildering world. We want to make sense of what we see around us and to ask: What is the nature of the universe? What is our place in it and where did it and we come from? Why is it the way it is?

Time travel was once considered scientific heresy, and I used to avoid talking about it for fear of being labelled a 'crank.'