A Brief Explanation of SETI
SETI is an acronym for the “Search for ExtraTerrestrial Intelligence.” SETI is not a single group or project; it is a blanket term for the scientific effort to find evidence of civilizations in the universe. SETI projects have ranged from early efforts of Nicola Tesla to intercept radio waves from Mars to more modern radio astronomy searches such as Project Ozma and Cyclops. Arguably, even the inclusion of an audio disc and special cover plate (complete with a visual message) on the Voyager space probes were SETI projects. The Soviet Union and other countries also have histories of SETI efforts. Given the vast distances between Earth and other potential technologically advanced civilizations most programs concentrate on detecting radio waves of a demonstrably intelligently made nature. Often the term SETI will be used incorrectly to refer specifically to the California based non-profit SETI Institute.
The Drake Equation
The basis on any SETI effort is the belief that there are other advanced civilizations in the galaxy that are broadcasting intelligent signals into space, whether intentionally or accidentally. Earth has been generating artificial signals for approximately one hundred years in the form of radio and television broadcasts. In 1961, Dr. Frank Drake created a formula to predict the number of technically advanced civilizations currently generating signals that may be able to be received by others. Although a relatively simple equation mathematically speaking (it is basically a mulitiplication problem with fractions), the formula contains several variables to account for factors such as the chance of such a society developing, the chance that they have the technology to generate signals and even the assumed lifetime of such a civilization. Most of the variables can only be assigned an assumed value, as one cannot be sure, for example, how long the typical civilization may broadcast radio signals. The result is a wild swing in the result (depending on the estimates used for the variables) ranging between thousands of possible civilizations generating intelligent signals and none. Nonetheless, with modest assumptions placed in the variables, the Drake Equation does seem to indicate that other intelligent civilizations exist. It should be noted that the Drake Equation is sometimes misrepresented as an attempt to quantify the number of planets in the universe with life or number of civilizations in the universe. It is neither; the Drake Equation is an attempt to identify the number of likely civilizations in our galaxy currently generating artificial, intelligent signals.
The SETI Institute
Although there have been several SETI projects over the last few decades, the term is most frequently connected with the SETI Institute. This 501(c)(3) non-profit research organization was legally established in late 1984. An outgrowth of earlier NASA funded projects, the SETI Institute was specifically created to explore all aspects of the Drake Equation. Although the many assume that it is exclusively a project devoted to radio astronomy, it is actually comprised of three divisions. Most commonly associated with the SETI Institute is its Center for SETI Research which concentrates on using radio telescopes in an attempt to detect intelligent signals from space. The Carl Sagan Center for Study of Life in the Universe is the Institute’s branch dedicated to astrobiology research. Finally the Center for Education and Public Outreach connects educators, students and other interested parties with the programs and discoveries of the SETI Institute.
Today, the SETI Institute employs over 100 and has completed more than 130 multi-year projects. In addition to a user-friendly website and opportunities for the public to contribute, the SETI Institute produces a weekly podcast called Big Picture Science. It is also engaged in building the Allen Telescope Array, its own dedicated radio telescope. Instead of one, extremely large dish the Allen Telescope Array is actually a network of dozens of small dish antennas, much like those used to receive pay television signals, working in cooperation. When completed the network will be comprised of 350 small dishes and will be powerful enough to simultaneously work on traditional radio astronomy research and SETI projects. Several well known scientists are associated with the SETI Institute as well. Dr. Frank Drake is the Chairman Emeritus of the Institute. Dr. Seth Shostak, an astronomer known for his numerous television appearances, and Dr. Jill Tarter, the inspiration for the main character in Carl Sagan’s Contact, are both SETI Institute scientists.
Other Current SETI Projects
Although the SETI Institute is probably the most recognized SETI group today, possibly thanks to the efforts of its Center for Education and Public Outreach, it is not the only scientific project searching for signs of intelligent life in the universe. There are Australian and Italian SETI groups as well as projects at UC Berkeley, Harvard and Ohio State. One of the most popular programs is SETI@Home, run by UC Berkeley. This cloud computing effort allows the massive amounts of data generated by UC Berkeley’s SETI efforts to be analyzed by volunteers’ home computers. When a computer with the SETI@Home software “sleeps” it runs a screen saver that is actually downloading and analyzing radio telescope data.
For Further Information
The Official SETI Website: http://www.seti.org
SETI@Home Website: http://setiathome.ssl.berkeley.edu/