Graham, Thomas (1805-1869), a Scottish chemist. He was a pioneer in the study of the mixtures called solutions, and originated the branch of chemistry that deals with colloidal solutions. In 1834 he formulated Graham's Law, which states that the relative speeds of the diffusion of gases are inversely proportional to the square roots of their densities. Graham attended the universities of Glasgow and Edinburgh. He was a professor at the University of London, 1837-55, and was appointed master of the mint in 1855.
He's ventured to the abyss of black holes, wagered on the information paradox and floated around in zero gravity. Meet the man, the legend, the super scientist: Stephen Hawking.
He is famous for a phrase he never said, for wearing turtlenecks and for hosting the original 'Cosmos' TV series. As enthusiastic about the stars as he was about marijuana, Carl Sagan led a very surprising life. Here are 10 cool facts.