And the year before that gave us Dissolving the Fermi paradox[1], which conclusively shows that the drake equation is not worth the napkin it's written on. tl;

And the year before that gave us Dissolving the Fermi paradox[1], which conclusively shows that the drake equation is not worth the napkin it's written on. tl;dr: It is possible for both of the following statements to be true at the same time: (1) The Drake equation gives a true estimate for the mean amount of extant civilizations in the galaxy, and that estimate is relatively large. (As in, much greater than one.) (2) The probability of sentient life existing outside our solar system is infinitesimally small. The reason for this is that the Drake equation gives a mean over all possible universes, with the solution space created by our uncertainty in the parameters. Since all of the parameters have more uncertainty in one direction than the other, the probability distribution is not symmetrical, and so the mean, mode and median are not the same. In fact, it turns out that when you do the math right, you find that essentially all of the probability mass in the Drake equation comes from the cases where almost every star has a civilization around it. Using our current best estimate numbers, and excluding the cases we can conclusively disprove because we are not already chatting with our neighbors at Proxima Centauri, P(we are alone in the galaxy) > 50%, and P(we are alone in the observable universe) > 39%. [1]https://arxiv.org/abs/1806.02404 https://arxiv.org/abs/1806.02404