Estimate how many communicating civilisations might exist in our galaxy with the Drake equation — set each factor below (fractions as percentages) and see the resulting number N.
The Drake equation, formulated by Frank Drake in 1961, estimates the number N of civilisations in the Milky Way we could potentially communicate with. It multiplies a chain of factors: the rate of suitable star formation, the fraction with planets, habitable planets per star, and the fractions that develop life, intelligence and communication, times how long such civilisations last.
Most factors are highly uncertain, so the equation is less a precise prediction than a framework for thinking about the ingredients for extraterrestrial life. Enter percentages for the fractions; the calculator converts them automatically.
It is N = R*·fp·ne·fl·fi·fc·L — a formula that estimates the number of communicating civilisations in our galaxy by multiplying together factors about stars, planets and the emergence of life.
Astronomer Frank Drake in 1961, as a way to organise the discussion at the first SETI meeting on the search for extraterrestrial intelligence.
It depends entirely on the assumptions — estimates range from less than one to millions. Because several factors are poorly known, it is a framework for thinking rather than a firm prediction.
We only have one example of life-bearing planet (Earth), so fractions like how often life becomes intelligent or communicative, and how long civilisations last, are essentially guesses.