Does anyone remember the formula for the probability of other habitable planets supporting intelligent life?

Question

It was something like number of stars in galaxy times number of planets times something times something. Also do any of our recent extra solar planet discoveries alter the equation?

Answer 1

The Drake equation is what your looking for

http://en.wikipedia.org/wiki/Drake_equation

where: N is the number of civilizations in our galaxy with which we might expect to be able to communicate at any given time
and

R* is the rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of the above that are willing and able to communicate
L is the expected lifetime of such a civilization

Answer 2

The Frank Drake Equation:
From the Astronomer and Science Fiction author of the same name.

Rate of demise =N/L = R, fP nE fL fi fC = rate of formation

N/L = R(f--planets )(n--Environments )(f--Life)( f--Intelligence )(f--Communication)

N = The number of technological civilizations able to
communicate with humanity
L = Average lifespan of a technological civilization
R = The rate of star formation
fP = The fraction of those stars that have planetary systems
nE =The mean number of planets in each system that
have environments favorable to life
fL = The fraction of those planets that actually developed life
fi = The fraction of those that evolved intelligent species
fc = The fraction of intelligent species that developed
sufficient technology for interstellar communication

Example
L= 50,000 light years (10 X time of human recorded
history)
R = 10 stars per year
f--P = 0.5
n--E = 1.0
f--l = 0.2
f--i =0.2
f--C =0.2

N = 400

50,000/400 = (10stars/year) (0.5) (1.0) (0.2) (0.2) (0.2) (0.2)

Answer 3

oh wow! you guys are Smart here! No kidding. So what planet completes or follows the Drake Equation?

Answer 4

This site gives both the formula and the explaination