Aug 26 2011 Are We Alone In the Universe? New Analysis Says
Maybe [Excerpts] Scientists engaged in the search for
extraterrestrial intelligence (SETI) work under the assumption
that there is, in fact, intelligent life out there to be found.
A new analysis may crush their optimism. To calculate the
likelihood that they'll make radio contact with
extraterrestrials, SETI scientists use what's known as the Drake
Equation. Formulated in the 1960s by Frank Drake of the SETI
Institute in California, it approximates the number of radio-
transmitting civilizations in our galaxy at any one time by
multiplying a string of factors: the number of stars, the
fraction that have planets, the fraction of those that are
habitable, the probability of life arising on such planets, its
likelihood of becoming intelligent and so on. The values of
almost all these factors are highly speculative. Nonetheless,
Drake and others have plugged in their best guesses, and
estimate that there are about 10,000 tech-savvy civilizations in
the g