The Drake Equation

12.7 - Understand how factors in the Drake equation can be used to allow us to estimate the number of civilisations in our Galaxy

The Drake Equation was proposed by Dr Frank Drake in 1960 as a model for scientists to estimate the probability of life and intelligent civilisations that use at least the same technology as us elsewhere in the galaxy.

It is an interesting exercise and worth doing to get your own estimates. In the scientific community there is disagreement about the merits and estimates involved in the Drake Equation.


Drake Equation
Drake Equation key to information
N  =   Number of civilizations in our galaxy with which communication might be possible;
R*  =   Average rate of star formation in our galaxy
fp  =   Fraction of those stars that have planets
ne  =   Average number of planets that can potentially support life per star that has planets
fl  =   Fraction of the above that actually go on to develop life at some point
fi  =   Fraction of the above that actually go on to develop intelligent life
fc   =   Fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L   =   Length of time such civilizations release detectable signals into space.

Arecibo Message

N = R* x fp x ne x fl x fi x fc x L

What do you think?

Figures from 0.01 to 5,000 have been published. At the time Drake's team estimated 10.


SETI Drake Equation