There is a new paper from Oxford University that says there is a 53% possibility that the humankind is alone in the Milky Way and another 40% possibility that there is no one but us in the visible universe. That is a sad perspective that was calculated through applying estimated (to say guess) values to the Drake equation:
N= R∗ x fp x ne x fl x fi x fc x L
N = the number of civilizations in our galaxy with which communication might be possible
R∗ = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations)
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space
Traditional answer to N uses to be near to 20.
The academics try to address the known as the Fermi Paradox, that calculates the possible colonize of the Milky way by an intelligent specie in a few tens of million years. You can see the paper here: https://arxiv.org/pdf/1806.02404.pdf
Although is true that we cannot assume that the values utilized are closer to the reality, we cannot either suppose the opposite. The Drake Equation was always based on estimates and we have to let the millennia elapse in order to discover the rough value that we should apply to every factor on the calculation.
Having all that in mind, I’ve preferred to still believing on the previous and more optimistic number, because… Is not a better universe the one with at least one intelligent species in it?
LA GALAXIA ELÍPTICA 