The Drake Equation

The Drake Equation

If you aren't familiar with the Drake Equation, it was formulated by astronomer Frank Drake in 1961. It provides a probabilistic method of estimating the number of technical civilizations that might exist in our galaxy. It combines 7 parameters that make up the components of the estimate.

Our dilemma is that we don't know very well what values many of those parameters may be. We can come close to estimating the N^* star formation rate, and we know now that most stars (f_p) have planets. But after that, the values of the other parameters are unknown, though the percentages for number of planets that will develop life (f_l), percentage of those that will develop intelligent life (f_i), and percentage of those that will develop technology (f_c), are all likely small values.

We also don't know how long a civilization tends to last (L). We have been a technical civilization a very short time, yet we already have the potential to destroy ourselves. So if we are a typical technical civilization, our predicament may suggest that the length of time a technical society exists could be rather short.

 The SETI Project is the project that is using radio telescopes to search for signals in space that may be being produced by other intelligent civilizations in our galaxy. That and our multiple projects involved in locating planetary systems outside of our own are helping refine our knowledge about the parameters included in the Drake Equation.

At any rate, play with the equation if you like, and see what possibilities you may come up with.

The formulation of the Drake Equation used:

N = N* . fp . ne . fl . fi . fc . L N* Star Formation Rate/Year fp Percent of those stars with planets ne Average number of life-potential planets per star fl Percent of those that will harbor life fi Percent of those that will develop intelligent life fc Percent of those that will develop radio communications L Number of years a civilization will exist

N*, Star Formation Rate 1 2 3 4 5 6 7 8 9 10 1 to 10 fp, Percent of Stars With Planets 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 5% To 90% ne, Avg Number of Life Potential Planets Per Star 1 2 3 4 5 6 7 8 9 10 1 To 10 fl, Percent Of Those That Will Develop Life 1% 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 1% To 100% fi, Percent Of Those That Will Develop Intelligent Life 0.01% 0.1% 1% 2% 5% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0.1% To 10% fc, Percent Of Those That Will Develop Radio Communication 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 1% To 50% L, Number Of Years A Civilization Will Last 10 yr 100 yr 500 yr 1000 yr 5000 yr 10000 yr 50000 yr 100000 yr 1,000 To 10,000 Years Number Of Concurrent Civilizations