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The Drake equation isn’t really an equation. It’s a series of questions that help us to work out how many intelligent civilizations in the galaxy there are with the ability to communicate.

## Origin

The Drake equation was formulated by Dr. Frank Drake of the SETI institute, and is still used by scientists today.

## How to do a Drake equation

This is a Drake equation:

N = N* x Fp x Ne x Fi x Fc x L

«N*» represents the number of new stars born each year in the Milky Way.
Answer: Our galaxy is about twelve billion years old and contains roughly three hundred billion stars. So, on average, stars are born at a rate of three hundred billion divided by twelve billion equaling to twenty-five stars per year.

«Fp» is the fraction of these stars that have planets orbiting them.
Answer: Current estimates range from 20% to 70%.

«Ne» is the number planets per star that are capable of sustaining life.
Answer: Current estimates range from 0.5 to 5.

«Fl» is the fraction of planets in «Ne» where life evolves.
Answer: Current estimates range from 100% (where live can evolve, it will) down to close to 0%.

«Fi» is the fraction of habitable planets where intelligent life evolves.
Answer: Estimates range from 100% (intelligence has such a survival advantage that it will certainly evolve) down to near 0%.

«Fc» is the fraction of planets with intelligent life capable of interstellar communication.