Are there other intelligent civilizations out there? Although there has yet to be solid, tangible proof of advanced alien life beyond our planet, many scientists and organizations continue searching for these extraterrestrial civilizations. However, there is a theory — physicist Enrico Fermi's eponymous paradox — that illustrates the contradiction between the good chance that alien life exists and the aforementioned lack of evidence to back that up. A recent study has offered a new take on that classic paradox, and as it seems, the new interpretation suggests that humanity is the universe's, or at least the Milky Way's, only intelligent civilization.
Originally published on June 8 and recently posted on Arxiv, the study entitled "Dissolving the Fermi Paradox" was authored by Oxford University senior fellow Anders Sanberg, Oxford moral philosopher Tod Ord, and nanotechnology "founding father" Eric Drexler. As summarized by Universe Today, the researchers also revisited the Drake equation, which was proposed in the 1960s by astronomer Frank Drake, factoring in a number of variables to show how there are various places in our galaxy where one can find intelligent extraterrestrial life.
New variables, namely chemical and genetic transition models, were taken into account by the researchers, who then concluded that there is a "considerable amount of scientific uncertainties" in the equation. That's on top of the uncertainties already present in the equation's existing variables — the average rate of star formation in the Milky Way, the percentage of stars with planets, the number of planets that could support life, the number of plants that could facilitate life, the number of planets capable of developing intelligent life, the number of civilizations that could invent transmission technologies, and the length of time it might take to transmit those signals into space. All of these figures are multiplied by each other to come up with the likely number of intelligent civilizations in the Milky Way.
In an email sent to Universe Today, Sanberg explained the aforementioned uncertainties, which remain in place decades after the Drake equation was formulated. He said that it's common for people to guess the values corresponding to each of the variables, which creates results that are likewise purely based on guesswork.
"This often leads to overconfidence, and worse, the Drake equation is very sensitive to bias: if you are hopeful a small nudge upwards in several uncertain estimates will give a hopeful result, and if you are a pessimist you can easily get a low result."When trying to reinterpret the Fermi paradox, the researchers considered each of the parameters in the Drake equation as "uncertainty ranges," with a smallest and largest possible value based on what we know today about each variable. Universe Today noted that there are some values that are more certain than others, such as the number of planets in the Milky Way, based on recent studies on exoplanets, and the number of planets within a star's habitable zone.
After combining all the ranges, the researchers got a "broad spread" because there were so many parameters with uncertain values. But Sanberg told Universe Today that this spread helped him and his fellow researchers come up with a figure determining the likelihood that we are our galaxy's sole intelligent civilization, at least based on what we already know.
"One can have a situation where the mean number of civilizations in the galaxy might be fairly high – say a hundred – and yet the probability that we are alone in the galaxy is 30%! The reason is that there is a very skew distribution of likelihood."Sanberg added that further review of scientific literature could result in more "extreme" results, where there is a "stronger uncertainty" about our galaxy's number of civilizations, which suggests that there's a very good chance humanity is "alone" as an intelligent civilization.
"However, we *also* conclude that we shouldn't be too surprised if we find intelligence!" Sanberg hinted.
As stressed by Universe Today, the new study on the Fermi paradox does not absolutely say that humanity is "alone" and that it's impossible to find proof of extraterrestrial life, but merely says that it's likelier than ever that we might be the only advanced species in the Milky Way. As such, Sanberg stated that the search for extraterrestrial life (SETI) is definitely not pointless, though, at this point, there is so much uncertainty that needs to be reduced, largely through the many SETI initiatives being carried out at the present.