Fall 1999  Who’s Calling, Please? June Lecture by Jill Tarter of SETI by Tamara Homan |
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| As long as humankind has had some form
of self-awareness, we have lived in close relationships with one another. We define our
societies by how people form family groups, where we live, what languages we speak. We
differentiate ourselves from animals by our ability to reason logically, to create art,
and to shape our environment. Now, for the first time, we may have the technology to
define humankind in a new way: by our relationship to life elsewhere in our universe. The Search for Extraterrestrial Intelligence (SETI) has fired the imagination for years. Little green men populate classic sci-fi novels, and several of the top-grossing films of all time feature life forms from places far removed from our familiar home planet. But SETI is not about the little green men and bug-eyed monsters that pop off the covers of paperback books or the movie screens—far from it. SETI is about hard science, about patient data collection and thorough analysis to draw careful conclusions. Dr. Jill Tarter, director of the SETI Institute’s Project Phoenix in Mountain View, California spoke in June at a public lecture sponsored by MIRA. Why is SETI important? Possibly because finding extraterrestrial life would be important to us not merely as individual societies, but as a species. As fictional astronomer Dr. Eleanor Arroway said in the popular film Contact, it would be "the most important discovery in the history of history." When cultures first encountered one another on different continents, or even in new territory on the same continent, that contact wrought profound changes in both peoples. Imagine what changes will happen in response to discovering life elsewhere in the universe. The SETI search has taken many forms over the years. Originally, NASA sponsored SETI research, but Congress cut the funding for SETI in 1993 after spending millions of dollars to construct sensitive equipment to collect and analyze data. Enter Project Phoenix! Well named for the mythological bird that rises from its own ashes, Project Phoenix uses a variety of locations to continue that search, concentrating on Sun-like stars within 200 light-years of us. Phoenix also concentrates on looking for unique, narrow-band signals in the range of 1,000 to 3,000 megahertz, because they would most likely be produced by an intelligent sender. Naturally occurring signals tend to be wider and have more harmonics—in other words, "messier". The SETI Institute also uses the Targeted Search System, consisting of multiple subsystems to automate the search in the 1 to 3 gigahertz range to a high degree, reserving human analysis for only the most promising signals. The Follow-Up Detector Device subsystem, referred to as FUDD, alerts astronomers to signals that need attention. (Draw your own conclusions about the device "lovingly called Elmer" in Contact.) Phoenix began at Parkes, Australia; moved to Green Bank, West Virginia in 1996; and has been using the world’s largest telescope, in Arecibo, Puerto Rico, since 1998. |
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| Listen Up is another SETI Institute project. By building many smaller, cheaper telescopes to cover one square kilometer, much more of the sky can be covered, and data can be analyzed using a pseudo-interferometer approach, which helps to eliminate signals that do not come from the target star. Dr. Tarter spoke about using off-the-shelf technology to build the Project Listen Up equipment, including parts from some unusual sources, such as truck axles. Well, Clyde Tombaugh discovered Pluto using a telescope he built with parts from the cream separator on his father’s farm, so truck axles should work just fine, too. |
 A young member of the audience listens intently to plans for the future of the Search for Extraterrestial Life. |
| Another aspect to that all-important search for life elsewhere is SETI@home, which uses the Internet to link many computers in a single virtual network to analyze the enormous quantity of SETI data that has been collected. Because a mainframe or other large computer is just too expensive, instead SETI@home, which is part of Project SERENDIP, links many home computers together into a virtual network, individuals can download a screensaver from the SETI@home web site. The screensaver contains software that analyzes 300KB chunks of SETI data, which is then forwarded back to the SERENDIP team. Though this approach doesn’t allow real-time data analysis, the savings in computer time is enormous. According to the SETI@home web site, within the first ten days of the project, approximately 370,000 participants in 203 countries contributed slightly over 2000 years of computer time. The URL for the SETI@home web site is http://setiathome.ssl.berkeley.edu/. The SETI Institute’s web site is at www.seti.org. Check out these sites for more general and technical information about the search. |
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| The question of what type of life is "out there" has never been more current. We know that material from Mars lies on the surface of our own planet as meteorite residue. Many planetary astronomers postulate that Jupiter’s moon, Europa, may have a liquid ocean underneath its icy surface, which constantly moves much like the tectonic plates in Earth’s crust. As the astronomical community discovers more and more planetary systems, some with multiple planets, and realizes just how common both water and Sun-type stars really are, the future offers tantalizing possibilities. Perhaps tomorrow a SETI scientist will detect a signal with all of the hallmarks of intelligent life. We already know how to say, "Hello, this is Homo sapiens from planet Earth." Our most logical transmission right after that would be an electronic equivalent of "Who’s calling please?" Any intelligent response, no matter how far removed in time or distance, would change us forever. |
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