The Drake Equation

demonstrate an understanding of the individual factors contained in the Drake Equation and their implications for the existence of life elsewhere in our Galaxy

Is there life on other planets? Might we ever come into contact with other civilisations in our galaxy. Is there any way we could estimate how many such civilisations there are?

In 1960 Frank Drake created an equation which actually calculates the number of civilisations which we might be able, at some time, to communicate with.

Of course it cannot be a wonderfully accurate way of calculating such a thing but it is a useful tool for considering what factors might have an affect on the presence of extra-terrestrial life.

The number of civilisations, N, is given by the equation:

N   =   R*   x   f_p  x   n_e   x   f_l   x   f_i   x   f_c   x   L

     R* = stars formed per year in our galaxy

     f_p = what fraction of these stars have planets

     n_e = how many of these planets could support life

     f_l = what fraction of these go on to develop life

     f_i = what fraction of this life is intelligent

     f_c = what fraction of these develop technology that make them detectable to other civilisations in space

     L = for how long they release such signals

The values for the factors above are either very hard to estimate or very much up for debate however, based on current estimates by some scientists,

N = 7 × 0.5 × 2 × 0.33 × 0.01 × 0.01 × 10000 = 2.31    i.e. we are not alone!