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Guest Editorial

Finding a Benford Beacon
by Paul Gilster
Centauri Dreams

It's heartening to see James and Gregory Benford's work on extraterrestrial beacons receiving broader coverage. News features like a recent one in TIME Magazine are pushing the Benford brothers' work out to a much larger audience. That's an important step, because right now the view of SETI most likely held by the average person relates to movies like Contact, in which huge dishes pointed at particular stars seem to be the way to proceed. The Benfords want to re-write that scenario in a big way.

We'll have to leave as debatable the question about how far away our own television transmissions can be received. James Benford commented not long ago that a civilization of approximately our technological level would not be able to receive broadcast signals as weak as those we've sent out carrying the likes of Milton Berle and I Love Lucy. Presumably, a far superior civilization could find those signals, but the question for our SETI search is, what kind of signal is feasible for us to receive today, and where do we look?

I like the notion of applying economics to this issue, which is what the Benfords do in analyzing how cost-effective an interstellar transmission strategy would be for the civilization sending it. It turns out that short, powerful bursts sent out now and then are far more reasonable than continuous broadcasts, given the realities of energy usage on the interstellar level. We're a lot less likely to find such 'Benford beacons' if we aren't pointed at just the right place at just the right time. Could the 1970s-era 'Wow' signal have been a Benford beacon, one we lacked the resources to follow up on with sufficient rigor to track down its true nature?

Whatever it was, the 'Wow' signal stands as a reminder that there's a lot we aren't doing. Gregory Benford told TIME that adding up all the SETI observing time over the past half century yields only a few months of data. So what would the chances be of finding a sporadic burst given the listening time and strategies involved? All of which gets me to Project Argus, an inspiring attempt by the SETI League to enlist the service of amateurs in the cause of broadening SETI's reach. The ambitious goal is to deploy 5,000 small radio telescopes around the globe, providing what the SETI League calls 'the first ever continuous monitoring of the entire sky, in all directions in real time.'

The SETI League's approach involves amateurs putting up to a few thousand dollars into an amateur radio telescope capable of the microwave coverage Project Argus demands. What you get with 5,000 small telescopes is full-sky coverage with the ability to pick up microwave radiation from a technologically advanced civilization out to several hundred light years. In a recent post on a mailing list of space professionals, writer David Brin noted that targeted signals like those sent to other stars from the Evpatoria radio telescope in the Crimea would probably not be detectable by an Allen Telescope Array, whereas a Project Argus at full strength would have found them.

Paul Shuch, executive director emeritus of the SETI League, is well aware that Project Argus will have to grow from its current 150 or so installations to the requisite 5000 to be truly operational, but perhaps this is where a philanthropist with a SETI bent could make a difference. In any event, what Project Argus is doing is of so fundamentally different a nature than the SETI Institute's work that it's deserving of our support. A combination of approaches is all to the good, and Project Argus adds a component than in Benford terms is more likely to succeed.

So on with the Allen Telescope Array, but kudos as well to the hard-working SETI League and its attempt to set up the kind of observational effort that just might detect the next 'Wow' signal. We should also keep in mind the other Benford caveats, that the obvious direction to look is toward the center of the Milky Way, where civilizations around older stars might have a more advanced technology and might have chosen to deploy a beacon along the galaxy's radius. Short, powerful bursts are going to be tricky to catch, so the more eyes and ears on the case, the greater the chances of success. Project Argus is an apt name. The mythical Argus had 100 eyes and could see in all directions at once, perhaps just the ticket for finding another civilization.

Disclaimer: The opinions expressed in editorials are those of the individual authors, and do not necessarily reflect the position of The SETI League, Inc., its Trustees, officers, Advisory Board, members, donors, or commercial sponsors.

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