The Drake Equation is:
N =
R *
fp *
ne *
fl *
fi *
fc *
L
Original estimates[edit]
There is considerable disagreement on the values of these parameters, but the 'educated guesses' used by Drake and his colleagues in 1961 were:
[24][25]
- R∗ = 1 yr−1 (1 star formed per year, on the average over the life of the galaxy; this was regarded as conservative)
- fp = 0.2 to 0.5 (one fifth to one half of all stars formed will have planets)
- ne = 1 to 5 (stars with planets will have between 1 and 5 planets capable of developing life)
- fl = 1 (100% of these planets will develop life)
- fi = 1 (100% of which will develop intelligent life)
- fc = 0.1 to 0.2 (10–20% of which will be able to communicate)
- L = 1000 to 100,000,000 years (which will last somewhere between 1000 and 100,000,000 years)
Inserting the above minimum numbers into the equation gives a minimum N of 20 (see:
Range of results). Inserting the maximum numbers gives a maximum of 50,000,000. Drake states that given the uncertainties, the original meeting concluded that
N ≈
L, and there were probably between 1000 and 100,000,000 civilizations in the
Milky Way galaxy.
Also the existence of Aliens also explains Dennis Rodman.
