We all love hearing stories about aliens and extraterrestrials. But what if I told you that there is a probabilistic equation that is used by scientists to estimate the amount of active and communicative extraterrestrial civilizations there are in the Milky Way. It is called the Drake Equation and it was made by Frank Drake in 1961. In actuality, the Drake equation is not fact. It does not hold true because we do not know if extraterrestrials exist in the Milky Way. It is just an approximation and many of the values are subject to conjecture. Moreover, it was created to encourage scientific dialogue at a SETI meeting about the possibility of extraterrestrial intelligence, which is a subject that I personally think the scientific community needs to dedicate more time to. Drake has said that the meeting estimated that there are between 1,000 and 100,000,000 civilizations in the Milky Way galaxy. Moreover, if you plug in the minimum numbers the equation states there are a minimum 10, and if you plug in the maximum numbers the equation states there are a maximum of 100,000,000. This equation is not factual, but it definitely is a great place to start and something that propelled the scientific community to think more about extraterrestrial civilizations.
Sources: https://informationisbeautiful.net/visualizations/the-drake-equation/ and ch.24 of Bennett – The Cosmic Perspective
Maverick's Astroworld 