While we have never, ever found signs of life outside of our planet, a recent study, published in the Cornell University arXiv database claims that alien civilizations that were part of our galaxy have probably already killed themselves off already.
The new study employed the use of modern astronomy and statistical modeling in efforts to map the life and death of intelligent life forms in time and space across our Milky Way. These results, which are a more concise update to Search for Extraterrestrial Intelligence founder Frank Drake’s 1961 famous equation. Drake’s equation concerned a number of different variables used to determine just how many alien civilizations are detectable in the Milky Way. Some of the variables included the rate of formation of stars suitable for the development of intelligent life (number per year), the number of planets, per solar system, with an environment suitable for life, the fraction of civilizations that develop a technology that produces detectable signs of their existence, and the average length of time such civilizations produce such signs (years). This equation was made more popular by Carl Sagan in his 13-part mini-series Cosmos: A Personal Voyage.
Instead of going Drake’s route, the team consisting of three Caltech physicists and one high school student took a more practical approach. Their paper explains where and when life most likely would occur in our vast Milky Way while also identifying the most important component affecting its frequency: the tendency intelligent creatures have toward self-annihilation.
Jonathan H. Jiang is an astrophysicist at NASA’s Jet Propulsion Laboratory at Caltech and also one of the co-authors of the paper. “Since Carl Sagan‘s time, there’s been lots of research,” he told LiveScience. “Especially since the Hubble Space Telescope and Kepler Space Telescope, we have lots of knowledge about the densities [of gas and stars] in the Milky Way galaxy and star formation rates and exoplanet formation … and the occurrence rate of supernova explosions. We actually know some of the numbers [that were mysteries at the time of the famous ‘Cosmos’ episode].”
In order to get an idea of the development of intelligent life, the authors of the paper looked at a range of influencing factors such as how frequent radiation-blasting supernovas came to life, how probable, as well as the time needed, for intelligent life to evolve given the right conditions, how prevalent sunlike stars coincide with Earth-like planets, and just how often advanced civilizations would destroy themselves.
With all this in mind, they were able to determine the probability of life-based on these factors hit its zenith about 13,000 light-years from our galactic center and some 8 billion years after our galaxy formed. For comparison’s sake, our earth is nearly 25,000 light-years from the Milky Way center. Human civilization began to show on Earth roughly 13.5 billion years after the formation of the Milky Way.
What this means is that we on Earth, because of our galactic geography, were more than likely a frontier civilization. But, if we are to assume life, other than our own, does come to fruition fairly often, with the eventuality of becoming intelligent, the chances that there are other civilizations out there is high and they are centered around the 13,000-light-year distance, which is mainly due to the knowledge that sunlike stars reside there.
As the research continued, they found that whatever remaining civilizations that still exist are likely young ones, given the fact that intelligent life is quite likely to eliminate itself over long timespans. Why they would self-annihilate is an answer the researchers did not offer which brings up another question worth noting. Just how often do civilizations kill themselves? To determine this, researchers first must determine just how widespread alien civilization was, or now is. The fact that we have yet to see conclusive evidence of these alien civilizations, leads to the notion that the majority of these possible civilizations are already gone.
Makes one wonder about all the UFO sightings the Navy finally fessed up to.