I think the next [21st] century will be the century of complexity. We have already discovered the basic laws that govern matter and understand all the normal situations. We don't know how the laws fit together, and what happens under extreme conditions. But I expect we will find a complete unified theory sometime this century. The is no limit to the complexity that we can build using those basic laws.

Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million. Our only chance of long term survival, is not to remain inward looking on planet Earth, but to spread out into space.

I have noticed even people who claim everything is predestined, and that we can do nothing to change it, look before they cross the road.

A million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe.

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.

The doctor who diagnosed me with ALS, or motor neuron disease, told me that it would kill me in two or three years.

Maxwell is the physicist's physicist.