US Radio astronomer Frank Drake developed the Drake equation so he could estimate the possible/probable number of planets containing intelligent life in the galaxy. He did this by taking into consideration the factors listed below, in preparation for one of the first “serious” discussions about the probability of life on other planets in the early 1960s. The factors are
N = the number of civilizations in our galaxy with which communication might be possible;
R* = the average rate of star formation per year in our galaxy
ƒp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
ƒℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
ƒc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time such civilizations release detectable signals into space.
Thus, what the Paradox is saying is that if so many planets exist or have existed with intelligent life, why is there a lack of contact between the intelligent life and us and why is there such a lack of physical evidence of said intelligent life here on earth, or elsewhere in the observable galaxy? The paradox exists in that the Drake equation statistically indicates life should be abundant and yet physical evidence says otherwise. In other words “where is everybody?”
To be fair the Drake Equation was only concocted to promote discussion and interest in the Search for Extraterrestrial Intelligent Life (SETI) and not to “prove” the existence of abundant life in the galaxy.
Opponents and critics of the Fermi Paradox say that there is evidence of extraterrestrial life, on this planet, now and throughout our history, and also from astronomical and other observations of space. But these have been suppressed by governments for a variety of reasons….