Abel, Sir Frederick Augustus (1827-1902), a British chemist. He was an authority on explosives. With Sir James Dewar, Abel invented cordite, a smokeless gunpowder, in 1889. From 1854 to 1888, Abel was chemist to the British War Department. He was created a baronet in 1893.
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.