The Drake Equation

Paddy Power offer 2/1 on alien life being discovered in the year 2020 or after, but I wonder what the odds of contacting intelligent alien life would be?
For those of you not involved in science, the Drake Equation is probably something that you have never heard of so if you lend me your ear I will share a few words of wisdom regarding its creation and its purpose. For those of you who know nothing about this equation, if you know how to multiply then you should be able to follow me.

The Drake Equation was proposed by a man named Frank Drake. Its purpose was to identify the number of alien civilisations within our galaxy that it may be possible to communicate with. Frank Drake and this equation worked to establish SETI (The Search for Extra Terrestrial Intelligence) as a scientific discipline. Since Drake first established his equation there have been many alterations to include new information and new variables. The Drake Equation states that:

N=R*Fp*Ne*Fl*Fi*Fc*L

Where:

N = The Number of civilisations within our galaxy with which it may be possible to communicate.
R = The rate at which suitable stars for life form in our galaxy.
Fp = The percentage or fraction of those stars that have orbiting planets.
Ne = The number of “earth like planets” per planetary star system.
Fl = The average number of planets that actually develop life, remember that some of these planets will be destroyed before life begins.
Fi = The fraction of Fl that develop intelligent life (e.g. like humans).
Fc = The fraction of Fi that will evolve far enough to emit signals (e.g. radio waves etc).
L = The amount of time that said civilisation will emit these signals

As you may have guessed some of the variables here are quite difficult to estimate. From the above scientists think that we know R, Fp and Ne with a good degree of accuracy but the rest are very vague estimates. Once you have estimated all your variables all you do is multiply them together, however because we really don’t know what some of these variables are the answers that you might see can be very different. For example when Drake first proposed the equation he estimated N = 10. Now some scientists think that the answer is closer to zero and others think that the answer could be in the hundreds of thousands.

However this equation alone only gives us an estimate of how many intelligent civilisations there MIGHT be in our galaxy. It does not tell us the likelihood of communicating with one of these civilisations. Remember that space is extremely vast and even if there were hundreds of thousands of these civilisations in our galaxy without knowing where to look it could still prove extremely difficult to make “first contact”.