Drake's formula: How many of them are out there?

Having gone through years of Math, Physics and Engineering, I’ve had my share of formulas. Many of them represent the most towering and spectacular achievements of the human brain; Newton’s F=ma, Einstein’s e=mc2, Boltzman’s S=k log W and Pythagoras’ a2 + b2 = c2.

But my favorite is the Drake’s formula. In fact, strictly speaking, it may not qualify as a formula at all; it’s speculative in nature. But its implications are profound.

Drake tried to estimate the number of civilizations in the universe (N).

Drake combines the following factors in his equation/formula:

a)What’s the average rate of star formation in the galaxy? (R’)

b)What fraction of stars have planets? (fp)

c)How many planets per star are capable of supporting life? (ne)

d)What’s the likelihood of intelligent life developing on these? (fl)

e)What fraction of these would be willing to communicate with other civilizations? (fc)

f)How long will such civilizations last, on an average? (L)

N = R’ * fp * ne * fl *fc * L

As you will notice, except the first factor, which is more or less well known (R’ = 10), putting a value to all others is guesswork. Worse, we have only ourselves to go by, and that can create biases.

However, the amazing thing is that for N to be greater than 1, L has to take the burden. Put simply, if there is any chance of more than 1 intelligent civilization capable of communicating across inter-stellar distances, it’s vitally important that they last a long, long time. Else, at any given point in time, there will be only one civilization and it’ll self destruct. A new one will emerge somewhere else later.

An interesting point that comes out of this is that if another specie does contact us, it’ll be so far down the road in existence that it’d have found a way to co-exist with differences. It’ll have the technology to inflict violence, but it’ll also have the wisdom to be non-violent, unlike in the movies.