Thursday, May 29, 2014

The Drake Equation

The Drake Equation: The Search for ET

N = R* fp ne fl fi fc L   So what the heck is this anyway?  So glad you asked. It’s quite an intriguing formula and has to do with the probability of life existing somewhere “out there.”  In 1961, while working as a radio astronomer at the National Radio Astronomy Observatory in Green Bank, West Virginia Dr. Frank Drake established a scientific formula which became known as the “Drake Equation.” It was actually in 1960 that Drake began his personal search for extraterrestrial intelligence which, shortly afterwards, led to his establishing the SETI institute.

It’s an awesome concept which was put into an equation over 50 years ago. Although Drake made some assumptions to arrive at his equation, you must admit, it’s a great way to help us organize our thinking in the way we search for extraterrestrial life. In 1960 his search was called Project Ozma. As Drake said, “For all we knew, practically every star in the sky had a civilization that’s transmitting.” What he found was that every star is not home to an intelligent, communicative civilization. But even Carl Sagan said that SETI as a science should be pursued.

As we have learned over time, there are many variables with Drake’s formula. The first three quantities are ones we can observe with our current technology. It’s the last four terms where the math gets a little fuzzy. We can say that life is ‘possible’ but not that it actually exists. Scientists today are much more conservative with their estimate and some won’t even speculate. If there is life, what percent of that is intelligent enough to communicate with us? Drake’s answer was 1%. Even that was a guesstimate. Of that 1% what are the chances that it would communicate on a level we could understand?

This may all change, because today we are searching for exoplanets that resemble Earth in size and temperature. Transiting Exoplanet Satellite Survey (TESS) and the James Webb Space Telescope are both due to launch around 2018. They will be looking for Earth-like planets orbiting small stars. Their mission is to concentrate on atmosphere, gases, oxygen, water vapor or other gases that do not belong to ‘dead’ worlds. Sara Seager has revised the Drake equation to focus simply on the presence of any alien life. Her focus is on M stars, the most common. Her calculation suggested that two inhabited planets could be discovered during the next decade. 
N = N*FQFHZFOFLFS  This is the Sara Seager equation, a bit different than Drake’s original.
As for me, well I hope that we do find some fascinating, intelligent, and above all, friendly aliens that would be tolerant of us.

For more information on this topic, please visit:

Sara Seager: