In 1961, University of California, Santa Cruz, astronomer and astrophysicist Dr Frank Drake devised the Drake Equation. This controversial equation multiplied estimates of the following terms together:
The rate of formation of suitable stars.
The fraction of those stars which are orbited by planets.
The number of Earth-like worlds per planetary system.
The fraction of planets where intelligent life develops.
The fraction of possible communicative planets.
The “lifetime” of possible communicative civilisations.
Although the Drake equation currently involves speculation about unmeasured parameters, it was not meant to be science but rather intended as a way to stimulate dialogue on these topics. Then the focus becomes how to proceed experimentally. Drake used the equation to estimate that there are approximately 10,000 planets in the Milky Way galaxy containing intelligent life with the possible capability of communicating with Earth.
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