Amazing facts about space

Answer 1

In the 60's professor Frank Drake set out to calculate the chances of other intelligent life existing... Under his equation you divide the number of stars in a selected portion of the universe by the number of stars that are likely to have planetary systems; divide that by the number of planetary systems that could theoretically support life, divide that by the number on which life, having arisen advances to a state of intelligence; and so on. At every division, the number shrinks colossally, yet even with the most conservative inputs the number of advanced civilizations just in the Milky Way always works out to be somewhere in the millions.