It’s a question that humans have been obsessed with for generations: do aliens exist and, if they do, why haven’t they made contact?
In 1950, with recent UFO sightings fresh on his mind, physicist Enrico Fermi brought up this idea to colleagues at Los Alamos National Laboratory. Using his ability to make good estimates from limited data, something for which he was well-known, he concluded that Earth should have been visited many times before this point.
A decade later, Frank Drake took Fermi’s work a step further and attempted to find a systemic way to evaluate the probability of alien life. However, it is far from conclusive. Drake, himself, said it was a way of “organizing our ignorance” rather than a means to settle the debate.