The Drake Equation

This past weekend, my Dad and I took a rather exhausting, but exciting, motor coach tour from Washington DC to the wild mountains of West Virginia in order to ride a couple amazing train rides. I hope to write about the train rides soon but its been a crazy week since I got home and time is not permitting a whole lot of writing or reading (but I'm trying to catch up with you all!)

The first stop of our trip, however, was the National Radio Astronomy Observatory in Greenbank, located in the depths of Monongahela National Forest. About an hour from the observatory, no one's cellphone could get a signal - and it's by design - as the radio signal from cellphones and even digital cameras - interferes with the huge radio wave collection dishes.


The National Radio Astronomy Observatory (NRAO) operates the Robert C. Byrd Green Bank Telescope (GBT), the world's largest fully steerable single aperture antenna.

The GBT is described as a 100-meter (328 feet) telescope, but the actual dimensions of the surface are 100 by 110 meters. The overall structure of the GBT is a wheel-and-track design that allows the telescope to view the entire sky. The track, 64 m (210 feet) in diameter, is level to within a few thousandths of an inch in order to provide precise pointing of the structure while bearing 16,000,000 pounds of moving weight!

Used for scientific research into the wonders of our colossal universe, the isolated site was first used in the 1950's by a Dr. Frank Donald Drake to look for little green men.


Dr. Frank Donald Drake (born May 28, 1930, Chicago) is an American astronomer and astrophysicist. He is most famous for founding Search for Extra-Terrestrial Intelligence (SETI) and creating the Drake equation and Arecibo (located in Puerto Rico) Message. The Arecibo Message was a "greeting card" beamed out into space asking for alien life to get in contact with us "lonely" humans. As far as anyone knows, no alien has ever gotten the message.

The Drake equation (sometimes called the Green Bank equation) is an equation used to estimate the potential number of extraterrestrial civilizations in our own galaxy, the Milky Way. It is used in the fields of exobiology and the search for extraterrestrial intelligence (SETI). The equation was devised by Frank Drake in 1962.

The Drake equation states that:


where:

N = the number of civilizations in our galaxy with which communication might be possible;

and

R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fℓ = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time such civilizations release detectable signals into space

Values based on "current" best estimates,

R* = 7/year, fp = 0.5, ne = 2, fl = 0.33, fi = 0.01, fc = 0.01, and L = 10000 years
result in

N = 7 × 0.5 × 2 × 0.33 × 0.01 × 0.01 × 10000 = (only) 2.31 civilizations.

Which isn't very many given the billions of stars in the Milky Way. Many hours of effort have been expended searching for ET and as yet, no sign of any has ever been found.

What would happen if we did find such life?

humankind's radio, and later television, broadcasts have been beaming into the deep voids of space for nearly 100 years now, any ET would likely will learn of us humans by hearing and seeing such shows as news reports of violent war and silly shows like Howdy Doody, I love Lucy, Get Smart, and Gomer Pyle, USMC. I wonder what do sort of opinion of us humans might an ET form?

I personally hope there is other (putting aside the question of intelligence) life out there. I have not thought through the ramifications of what such life might mean, should we discover it (or it discovers us). I'm certain our world's religions would be greatly shaken, if not stirred.