And this is why: http://www.wimp.com/futurehumanity/
Carl Edward Sagan (English pronunciation: /ˈseɪɡən/) (November 9, 1934 – December 20, 1996) was an American astronomer,astrophysicist, cosmologist, author and science popularizer and science communicator in the space and natural sciences. During his lifetime, he published more than 600 scientific papers and popular articles and was author, co-author, or editor of more than 20 books. In his works, he advocated skeptical inquiry and the scientific method. He pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI).
Sagan became world-famous for his popular science books and for the award-winning 1980 television series Cosmos: A Personal Voyage, which he narrated and co-wrote. A book to accompany the program was also published. Sagan also wrote the novel Contact, the basis for the 1997 film of the same name.