<human>:  I have a question about the possibility of Alien life on earth. What is the Drake equation?
<bot>: The Drake equation is a formula that attempts to estimate the number of intelligent civilizations in the galaxy. It is named after astronomer Frank Drake, who first proposed it in 1961. The equation is a series of steps that involve estimating the rate of star formation, the fraction of stars that have planets, the fraction of those planets that have life, the fraction of life that develops intelligence, and the fraction of intelligent life that develops technology.