By Tim Binnall
A somewhat dispiriting new study suggests that it could take a staggering 400,000 years before humanity establishes contact with advanced extraterrestrials. The intriguing thought experiment is reportedly the work of astronomers Wenjie Song and He Gao, who pondered how many ET civilizations might exist in our galaxy and, in turn, the probability for communication with one of them. The challenge of such an inquiry, they conceded, is that much of it is hypothetical since they only have "a single known data point," in the form of humanity, which can serve as an example of intelligent life arising in the cosmos.
Having acknowledged that intellectual impediment, the pair set about trying to answer their question of when we might hear from aliens by looking at the probability of such an ET civilization coming to fruition at different points in the evolution of a star's lifetime. By running a series of mathematical models wherein they varied the possible number of habitable worlds in our galaxy as well as when life might arise on those planets, the astronomers produced scenarios both good and bad. On the more optimistic end, if intelligent life can arise early in a star's lifetime, there may be 42,000 such civilizations in our galaxy and it might only be a 'mere' 2,000 years until we hear from one of them.
However, if the emergence of intelligent life is dependent on a star being considerably older, they determined that this would only produce around 111 alien civilizations in our galaxy. Should that scenario be more in keeping with reality, they found that it could take a heartbreaking 400,000 years before two-way communication with ETs can ever occur. An additional variable that the scientists stressed considering is what is known as the 'Great Filter,' which is a concept that suggests that intelligent civilizations may actually not last very long, relative to space time, since they all manner of doomsday scenarios, either natural or by their own hand, could cause their extinction.