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Projects: SETI Radio SearchesSouthern SETI
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The two 30 meter dishes at IAR in Argentina. Credit: IAR/Guillermo Lemarchand |
Project UpdatE:
February 26, 2007: Keeping an Ear to the Center of the Galaxy, Southern SETI Prepares for Great Leap Forward"
Did you know that Southern SETI in Argentina...
- is the only sustained SETI project based in the southern hemisphere;
- is the world’s only sustained SETI project that can listen to the center of the Milky Way, where most of the stars in our galaxy are located;
- is now adopting a unique search strategy focused on “masers” -- natural amplifiers in the sky that could be used by aliens to transmit their signal;
- with backing from The Planetary Society, Southern SETI is gearing up for a giant leap forward -- an upgrade to SERENDIP V, the most cutting-edge radio SETI system in existence.
The Planetary Society's Southern SETI project is the only sustained Search for Extraterrestrial Intelligence (SETI) project in the southern hemisphere. Since 1986, scientists have used two 30-meter dishes at the Instituto Argentino de Radioastronomia (IAR), 35 kilometers south of Buenos Aires, to scan the entire southern skies no less than six times at several different frequencies. They've sifted through mountains of data looking for that elusive signal from aliens, but have yet to find it. But they know that just one faint signal from a distant civilization would change our view of our place in the universe, so they continue the search.
Operating the only continuous radio SETI project in the southern hemisphere carries with it some special responsibilities. This is because the center of our galaxy, the Milky Way, is rarely visible above the horizon north of the equator, but is clearly visible from the south. As it happens, the center is by far the most star-rich region of our galaxy, with a star density 100 times greater than the periphery. The center of the Milky Way contains billions upon billions of stars, each of which may be home for an advanced alien civilization. If a signal from any of these stars is trying to reach us, only Southern SETI is likely to hear it.
Southern SETI has an additional advantage over most other searches: most SETI projects are based at busy radio telescopes such as Arecibo, where competition for observation time is fierce. This means that most SETI projects either settle for short dedicated observation sessions, or else they “piggyback” on the telescopes normal operations, listening in whichever direction the telescope happens to be pointing. At IAR, in contrast, SETI scientists have almost unlimited observation time, and they can point the telescopes in whichever direction they wish for hours at a time.
Today, with backing from The Planetary Society, Southern SETI is gearing up for a giant leap forward. Since 1990, the project has been operating with META II electronics. This was an exact copy of the META (for “Million-channel Extraterrestrial Assay”) system that was used by Paul Horowitz in his SETI project using the 80-foot dish at the Oak Ridge Observatory in Massachusetts. The system was at the cutting edge of technology at the time, but after more than 16 years of operation, it is clearly showing its age. If funding becomes available, Southern SETI will replace META II with a new system called SERENDIP V, designed and built by Dan Werthimer’s U.C. Berkeley team of SETI@home fame. Once in place, the new system will increase the number of channels Southern SETI can monitor by 15-30 times, and the overall range of frequencies by 325-650 times! In addition, SERENDIP V, unlike META II, is portable, and can be attached to other radio telescopes around the world.
Guillermo Lemarchand, Southern SETI Project Director
Credit: IAR/Guillermo Lemarchand |
Once SERENDIP V is installed at IAR, its first assignment will be to launch Southern SETI’s most innovative search yet: listening for signals emanating from masers in the sky.
Masers (the microwave version of a “laser,” stands for “microwave amplification by stimulated emission of radiation”) are made up of diffuse clouds of gas, floating in deep space, and in themselves they are of no particular interest for SETI researchers. Masers do, however, have one remarkable characteristic: they can amplify radio signals that pass through them at certain specific frequencies by tens of millions to hundreds of billions of times. Isn’t it likely that technologically advanced aliens, trying to get their signal across the vastness of space would make use of these "amplifiers in the sky"? Guillermo Lemarchand, leader of Southern SETI, thinks that it is.
And so, with sparkling new hardware, cutting-edge technology, and a groundbreaking innovative strategy, the search continues. And if an alien civilization from the center of the galaxy is trying to communicate with us, using masers to amplify their signals, then Southern SETI is there, listening for their call.
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