Of the many "maybe’s" that SETI has turned up in its four-decade history, none is better known than the one that was discovered in August, 1977, in Columbus, Ohio. The famous Wow signal was found as part of a long-running sky survey conducted with Ohio State University’s "Big Ear" radio telescope.

The Wow signal’s unusual nomenclature connotes both the surprise of the discovery and its sox-knocking strength (60 Janskys in a 10 KHz channel, which is more than 50 thousand times more incoming energy than the minimum signal that would register as a hit for today’s Project Phoenix.)

But is the Wow signal’s notoriety merely the triumph of marketing over substance? Could this momentary cosmic burp have really been ET, or was it just random terrestrial interference dressed up with a sexy moniker? For a decade, Robert Gray, a long-time, independent SETI researcher from Chicago, has been trying to find out.

Gray, like many others, was attracted by an intriguing feature of the Wow signal: the manner in which it rose and fell over the course of 72 seconds. Why is this interesting? Just this: the Ohio State survey kept the telescope fixed, letting the Earth’s daily spin rotate the heavens through its narrow beam. The "beam," of course, was the elongated patch of sky to which the telescope was sensitive – the direction from which it could pick up cosmic signals. The sensitivity was greatest at the center of the beam, falling off to either side. So as a celestial radio source passed by, it first rose in apparent intensity as Earth’s rotation brought it into the beam, reached a peak in the beam center, and then faded away. Given the size of the Ohio State beam, this rise and fall should take 72 seconds. And for the Wow signal, it did.

Now contrast this with what you’d expect if the telescope had merely been briefly flooded by an interfering terrestrial signal. The intensity would suddenly switch full on, and then, sometime later, switch off. Even if the interference was due to a low-Earth orbit satellite, a source that might cause a rise and fall in intensity, you wouldn’t expect it to fortuitously last for 72 seconds.

For these reasons, the Wow signal gets high marks for being a credible candidate for SETI.

On the other hand, there are some aspects of this seductive signal that nudge it toward a lower grade. The Ohio State telescope actually used two beams, situated side-by-side on the sky. Any cosmic source would therefore be seen first in one (for 72 seconds) and then – roughly 3 minutes later – in the other (also 72 seconds.) The Wow signal failed this simple test. It came on gangbusters in one beam, but was a no-show in the other: suspicious and disheartening.

But as Gray and others have realized, this odd, one-beam behavior could be caused by an alien transmission that simply went off the air during the 3 minutes between beams. Maybe ET went on vacation, or took an extended lunch break. If the putative aliens permanently shut down their transmitter, then there’s no chance of ever hearing the Wow signal again. Like a single sighting of the Loch Ness monster, we would never be able to prove what it was. But if the signal is periodic – if, for example, the aliens are using a rotating radio beacon that sweeps the star-studded strata of the Milky Way once every five minutes or every five hours – then we could hope to find it by just looking again.

Robert Gray has looked again. And again. In the last decade, Gray and his colleagues have used the Harvard META SETI system and then the Very Large Array (VLA) to search for a reappearance of the Wow signal. The experiment at the VLA, in particular, was an impressive effort, as it was far more sensitive than the original Ohio State equipment and covered more of the band. Neither attempt succeeded in retrieving the signal, however.

Gray realized that he might be the victim of insufficient patience. The longest of his reobservations had been 22 minutes. What if the aliens’ beacon flashed less often than once every 22 minutes? What if their transmitter was fixed to the home planet, rotating (and flashing) once every 20 or 30 hours?

In the October 20 issue of The Astrophysical Journal, Gray and Simon Ellingsen, of Australia’s University of Tasmania, report on new observations (partially supported by the SETI Institute) designed to test this idea. Their new try was made at the 26-meter radio telescope in Hobart, Tasmania. This southern hemisphere instrument could continuously follow for most of a day the patch of sky (in the constellation of Sagittarius) where the "Big Ear" was pointing when it found the ‘Wow’ signal. They made six 14-hour observations, and even though their telescope was rather smaller than the venerable Ohio State antenna, they still had sufficient sensitivity to find signals only 5% as strong as Wow’s 1977 intensity. They also covered five times as much of the radio dial as the original "Big Ear" telescope.

Bottom line? No dice. To quote from their article, "no signals resembling the Ohio State Wow were detected…" Of course, if the signal’s repetition cycle were much longer than 14 hours, then even this careful experiment could have easily missed it. But as Gray and Ellingsen point out, if the signal were really this infrequent, then the chance to have found it in the first place was very slim.

So was the Wow signal our first detection of extraterrestrials? It might have been, but no scientist would make such a claim. Scientific experiment is inherently, and rightly, skeptical. This isn’t just a sour attitude; it’s the only way to avoid routinely fooling yourself. So until and unless the cosmic beep measured in Ohio is found again, the Wow signal will remain a What signal.

. . .(in the constellation of Sagittarius) where the "Big Ear" was pointing when it found the ‘Wow’ signal.

I've always wondered about this since the galactic center happens to lie in the direction of Sagittarius. In other words, was the 'Big Ear' telescope pointed right at the galactic core that night? I've never heard.

Of course, it could be just a coincidence. But there are lots of mega-energetic things going on in the vicinity of the galactic core that we don't understand and rather than attributing 'Wow' to ET, we've got to keep in mind that the signal may have a previously undiscovered natural origin. (Just don't ask me how a natural phenomenon could emit a narrow-band burst!)

Either way, natural or artificial, it was a pretty nifty observation. Too bad they can't duplicate it. I'm glad they're not giving up.

http://www.s-t.com/daily/11-99/11-10-99/l01ae067.htm

Ferris makes his case about life ... somewhere out there

By John Rogers, Associated Press writer

There's a "Saturday Night Live" gag going back more than 20 years that still makes Timothy Ferris chuckle.
It seems those crazy Voyager folks put a bunch of Earth music on a record in 1977 and blasted it into outer space hoping that someone would be listening.

"Everything from Beethoven to Chuck Berry" was included, the story goes, and almost immediately it raised a reply in Martian-speak. When the folks at NASA finally translated it, it said:
"Send more Chuck Berry!"

That's the kind of attitude Timothy Ferris hopes people who see his new two-hour PBS documentary, "Life Beyond Earth," might have. Playful, irreverent and open to the possibility that maybe there are a few Chuck Berry fans out there, just waiting for a recording of "Johnny B. Goode" to float by.

"What I'm always most interested in doing in a film like this is in reaching people who don't think of themselves as interested in science," says Ferris, who produced the Voyager spacecraft record that "SNL" spoofed.

"It's most gratifying when you can find someone who isn't interested in science and take them down a path of learning."

It's the same path his parents took their 12-year-old son down in 1956 when they bought a $32 telescope and sent him out to the back yard with it.

"It was a terrible telescope," he remembers with a laugh. "No one could see anything through it except me and I couldn't see all that much. To change powers you had to take the eyepiece apart."

Still, when he saw Mars through the thing, he was hooked.

"Astronomy is kind of an amazing pursuit," he muses all these years later. "It became the central interest of my life, I guess."

So much so that the University of California, Berkeley, professor emeritus and former writer and editor for Rolling Stone magazine has written nine books on the subject, including, "Coming of Age in the Milky Way," which was nominated for a Pulitzer Prize. In 1985 he released the PBS documentary, "The Creation of the Universe."

His latest film, airing on PBS stations from 8 to 10 tonight, divides its subject matter into two parts.

The first, somewhat slower hour looks at how life evolved on Earth, setting the stage for the second half, in which Ferris and others take up the idea that if intelligent life could develop here, then why wouldn't it develop somewhere else?

Not everyone, of course, agrees. So to shoot down his critics' contention that if intelligent life forms really were out there they would have dropped in and said hello by now, Ferris at one point during the film dons a tux and sits down to a candlelight lobster dinner. The only thing missing is the lobster. But he's sure, he says, that if one is out there it will walk through the door sooner or later. When it doesn't, he still refuses to concede that it doesn't exist.

"Lobster have their own agenda," he tells the viewer. "They don't want to come to my house.

"I have an opinion, which is that life is abundant in the universe and that intelligent life is abundant as well," he says in a phone interview. "Of course my opinion is worth no more than anyone else's. What I'm optimistic of is that we're now really entering a period where it will be possible to replace these opinions with facts."

Only recently, he notes, has science discovered there are stars out there that have their own planets, just like our sun.

"That's a case of moving from an assumption to something that is inevitable," he says. "But we cannot yet take a picture of any of those planets."

What's more, he says, we aren't close to having the rocket power to travel the distances required to visit them. And perhaps neither do the life forms that may occupy them. "That would take enormous time and expense," he says.

So the best hope of finding someone out there, he concludes, is by sending out radio messages, something the Earth has only been doing for about a century. Add on a few more centuries, he says, and those messages might finally begin to reach somebody who will reply.

So when we finally find life in another galaxy we won't be communicating with it face-to-face but in some form closer to a telephone conversation.

"I don't know if there will ever be a lot of handshakes," Ferris says seriously.

Then he adds playfully: "Maybe that's not bad. Especially when you're dealing with someone who has 14 tentacles for hands."

Photo by The Associated Press
Timothy Ferris poses beside the Porsche he drives across the Utah desert on a road sectioned to represent the 5 billion years of the Earth's life in "Life Beyond Earth."

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