The Drake equation will reach its 65th anniversary in October 2026. Astrobiologist Frank Drake first proposed the mathematical formula in 1961.
Drake convened the inaugural scientific conference dedicated to the search for extraterrestrial intelligence (SETI). To encourage discussion among attendees at the SETI meeting, Drake sketched out the equation.
The equation serves as a method to estimate N, which represents the number of intelligent civilisations in the Milky Way galaxy that humans might eventually contact. Current measurements indicate that the Milky Way forms between 1 and 3 stars every year.
Data suggests that the fraction of stars possessing planetary systems, known as fp, is approximately 1. Our own solar system contains either 2 or 3 planets located within the habitable zone.
Researchers at the original SETI conference estimated N to be between 1,000 and 100,000,000. Calculations using the lowest possible estimates suggest N could be one-trillionth or even lower.
Conversely, the highest estimates indicate there could be tens of millions of communicable civilisations in the Milky Way.
