As Space exploration missions advance and search for alien life continues, recent research has suggested that our Milky Way Galaxy may contain alien civilizations. However, there is a strong possibility that most of them are already dead.
The research was carried out by California Institute of Technology, NASA's Jet Propulsion Laboratory, and Santiago High School and was published this month. Scientists used an expanded version of the famous Drake Equation, which determined the chances of extraterrestrial intelligence existing in our galaxy. The Drake equation was written in 1961 by Frank Drake which attempted to estimate the number of living and communicative alien civilisations in the Milky Way galaxy. The equation takes into account factors like rate of star creation, number of these with planets, and a fraction of planets that develop life. Drake equation was originally designed not to provide an exact number but rather stimulate debate on how many extraterrestrial civilisations are in existence.
In the recent study, which is yet to be peer-reviewed, researchers looked at various factors that could most likely lead to a habitable environment, and determined potential extraterrestrial intelligence (ETI) may have emerged in our galaxy about 8 billion years after it was formed. The research predicts that some of these civilizations could have been 13,000 light-years from the galactic center, about 12,000 light-years closer than Earth, where humans are believed to have emerged 13.5 billion years after the Milky Way galaxy was formed.
To draw their conclusions, scientists also considered typically overlooked factors such as the process of abiogenesis, which is the creation of organic molecules by forces other than living organisms, different evolutionary timescales and potential self-annihilation, exploring the growing propensity of ETI.
The study also considered factors that may have ended these civilizations, such as exposure to radiation, a sudden pause in evolution, and the tendency for the ETI to self-annihilate through phenomena like climate change, technological advancements, or war. This also derives that any existing alien civilisations are most likely young, as self-annihilation typically occurs after a long period.
The research mentioned that the existence of extraterrestrial intelligence is directly related to habitability and a galactic habitable zone (GHZ). Potential life is most likely to form on a habitable planet. To derive the results, researchers also developed a Lagrangian model with Monte Carlo techniques to accurately simulate each Earth-like planet in the Milky Way galaxy. Explaining the need to conduct this research the paper mentioned that missions like Search for ETI (SETI) have been heavily limited by the current technology and a lack of quantitative understanding of intelligent life on a galactic scale, and the answers to the absence of life discovery elsewhere have remained controversial.