Maybe its time to search for extraterrestrial civilizations that existed in a distant past?
A new research article published on arXiv.org presents an interesting statistical modeling of how intelligent life could have been distributed throughout the entire space of the Milky Way over the course of its existence.
According to different galaxy age estimation methods, our Milky Way is around 12-13 billion years old. From logical perspective, during such a vast time scale and given an extremely large number of stars contained in the galaxy, intelligent life forms could have emerged many times, in different locations. In the same way, those intelligent life forms could have gone extinct due to different reasons.
In a certain sense, the new paper improves the famous Drake equation, which since 1961 has been used to estimate the number of active civilizations in the Milky Way galaxy, based on a number of approximate parameters. The authors of this research present their own version which can ‘do’ a bit more: to tell where and when life could have formed, while also factoring in parameters potentially leading to its destruction, including possibility of self-destruction.
The authors say that 13,000 light-years distance from the galactic center is the most favorable place for life to emerge. The most favorable time would have been 8 billion years after the birth of the galaxy. This space and time frame would probably be the best to target with aim to find signs of extraterrestrial life. However, researchers conclude, that during such a long time scale most of the previous civilizations have, most likely, self-annihilated.
The researchers admit that the rate of self-destruction is the most approximate parameter in their modeling, because it is hard to tell based on the history of humanity alone. Although, even an extremely low chance of intelligent civilization self-destructing through no matter what mechanisms (e.g. climate change, war, etc.) would mean, that an absolute majority of civilizations at all their levels are already extinct.