Thursday, May 27, 2010

The Silence is Deafening

The Drake equation was developed by Frank Drake in 1961 to estimate the number of communicating civilizations in our galaxy
N = N* fp ne fl fi fc fL

N = the number of communicating civilizations in the galaxy.
N* = number of stars in our galaxy
fp = fraction of stars with planets
ne = number planets per star able to sustain life
fl = fraction of ne planets where life evolves
fi = fraction of those planets where intelligent life evolves
fc = fraction of fi that communicate
fL = the fraction of the planet's life during which the communicating civilizations survives

He solved it and got 10,000. 10,000 is a pretty small number amongst 200 billion stars in our galaxy. And so searching for ET by listening for intelligence in electromagnetic energy such as radio could take awhile. But what Drake did not consider was that technological growth is exponential not linear - surely civilizations would learn relatively quickly how to build artificial worlds even if they could not expand outward at greater than light speed. Given the multibillion year age of our galaxy even conservative estimates would thus solve the equation in the hundreds of thousands if not millions of civilizations range. The sky should be screaming at us - the silence to date, stunning. Where is everybody?

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