The Search for Extraterrestrial Intelligence SETI
The SETI Institute
What Is Seti ?
Since the earliest human civilizations and through the vast expansive corridors of time man has looked up at the night sky wondering and asking himself whether we are alone in the universe .It is only in the last century that scientist and ordinary people started seriously trying to answer this by using scientific methodologies. These endeavors by groups of loosely coordinated people, organisations, universities and institutes is commonly referred to by the acronym SETI which stands for the search for extraterrestrial life .The main organisations currently driving these efforts on a continuous basis are the SETI Institute, The SETI League, The Planetary Society and the Carl Sagan Institute amongst others. NASA (the National Astronautical and Space Administration) also had a SETI program but its funding was cut by Congress in 1993. We can then describe the search for extraterrestrial intelligence (SETI) as the cooperative actions taken by different groups and individuals to search for extraterrestrial life.
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The person associated with the first attempt at a SETI search was Frank Drake he did this in 1960 with Project Ozma .Frank Drake was a Cornel University astronomer at the time .He was based at the National Radio Astronomy Observatory at Green Bank, West Virginia .The objective of project Ozma was to study interstellar radio signals coming from space. Frank Drake used two radio telescope with a diameter of 85 feet pointed at two stars Tau Ceti and Epsilon Eridani. There were two Ozma experiments both using radio astronomy as a detecting technique. Both experiments turned out inconclusive but this did not hamper the effort.
One of the first SETI gatherings took place in a place called Green Bank West Virginia on November 1961 it was organised by Peter Peaman. There were 10 people in attendance these included Frank Drake, Philip Morrison, Dana Atchley, Melvin Calvin, Su-Shu Huang, john Lilly, Barney Oliver, Carl Sagan and Otto Struve. The purpose of the conference was to discus the Drake Equation, from the basic principles discussed during the conference Drake came up with what we now call the Drake equation. The Drake equation tries to estimate how many planets in our Milky Way are inhabited by intelligent civilisations. The SETI League states that the purpose of the equation is to provoke thought and debate and not to arrive at a definitive accurate answer.
The variables in this equation include:-
R =the rate of star creation in the galaxy, over billions of years stars spontaneously come into existence as a result of gravitational collapse of materials within gas clouds.
F (p) = the fraction of those stars that have planets, current observations have proves that planets revolving around stars are very common place.
N (e) = The average number of planets that can support life as we know it , that is planets in the ‘goldilocks zone’ which is the area that is not to far or to close to a star and in stable orbit which is another important factor.
f l = the fraction of planets that could support life that actually develop life at some point.
f i = the fraction of civilisations that develop a technology that release detectable signs of their existence into space
L = the length of time for which such civilisations release detectable signals into space.
Detecting Intelligent Life and the WOW ! Signal
The Drake equation itself is a pointer to scientist and researches alike as to how to go about detecting alien civilisations. The early methods used were listening to radio signals from outer space there are many groups around the world doing this. So far though SETI enthusiasts have not yet discovered any intelligent signal. Although there was one SETI program that detected what appeared to be a serious signal on August 15 1977, this signal was called the wow signal .The SETI group that detected this signal was based at The Ohio State University Radio Observatory. A volunteer named Jerry Ehman detected a very strong signal that was received by the telescope. On the print out he was reading he circled the series of computer generated numbers that represented the signal and in the margin he wrote the words Wow ! Signal! The only problem was that they were not able to detect the signal again. It is became accepted that this was the most credible candidate for a signal from an intelligent civilisation.
Another way to detect the presence of alien civilizations is to look for earth like planets orbiting around sun like stars. These planets are called extra solar planets the Kepler space telescope has been able to detect thousands of these with around 262 earth like planets amongst them. By extrapolating data collected so far astronomers say that the Milky Way Galaxy alone may contain up to 400 Billion exoplanets on average almost every star has a planet as a companion on their stellar journeys. SETI organisations have only just started no doubt as time passes they will eventually find a signal given the vastness of the cosmos.