The Drake equation is a famous result in the fields of exobiology and the search for extraterrestrial intelligence (SETI). This equation was devised by Dr. Frank Drake (now Professor Emeritus of Astronomy and Astrophysics at the University of California, Santa Cruz) in 1960, in an attempt to estimate the number of extraterrestrial civilizations in our galaxy with which we might come in contact.

The main purpose of the equation is to allow scientists to quantify the uncertainty of the factors which determine the number of such extraterrestrial civilizations.

N= R*x f_px n_ex f_lx f_ix f_cx L

• N is the number of civilizations in our galaxy with which we might hope to be able to communicate.
• R* is the average rate of star formation in our galaxy.
• f_p is the fraction of those stars that have planets.
• n_e is the average number of planets that can potentially support life per star that has planets.
• f_l is the fraction of the above that actually go on to develop life at some point.
• f_i is the fraction of the above that actually go on to develop intelligent life.
• f_c is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
• L is the length of time such civilizations release detectable signals into space.