Stephen Hawking

A specialist in cosmology and quantum gravity and a devotee of black holes, Stephen Hawking probed the origins of the cosmos, the nature of time and the universe's ultimate fate -- earning him accolades including induction into the Order of the British Empire. To the public, he's best known as an author of bestsellers such as The Universe in a Nutshell and A Brief History of Time, which have brought an appreciation of theoretical physics to millions.

Though the motor neuron disorder ALS confined Hawking to a wheelchair, it didn't stop him from lecturing widely, making appearances on television shows such as Star Trek: The Next Generation and The Simpsons -- and planning a trip into orbit with Richard Branson's Virgin Galactic. A true academic celebrity, he used his public appearances to raise awareness about potential global disasters -- such as global warming -- and to speak out for the future of humanity: "Getting a portion of the human race permanently off the planet is imperative for our future as a species," he said.

Hawking served as Lucasian Professor of Mathematics at the University of Cambridge, where he contributed to both high-level physics and the popular understanding of our universe.