Interstellar Signal from the 70s Continues to Puzzle Researchers

[Jennie McGrath]

Interstellar Signal from the 70s Continues to Puzzle Researchers

By Seth Shostak
SETI Institute
posted: 07:00 am ET
05 December 2002

Of the many "maybes" 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 Universitys "Big Ear" radio telescope.

The Wow signals 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 todays Project Phoenix.)

But is the Wow signals 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 Earths 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 Earths 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 youd 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 wouldnt 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 theres 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 Australias 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 Wows 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 signals 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 isnt just a sour attitude; its 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.


http://www.space.com/searchforlife/seti_shostak_wow_021205.html

[Jennie McGrath]

Planetary News: SETI (2001) The "Wow!" Signal Still Eludes Detection

By Amir Alexander

Whatever happened to the "Wow!" signal, the most promising transmission from space ever detected by SETI? Ever since it was recorded almost a quarter of a century ago, SETI enthusiasts have speculated about its origin and wondered whether it could be a beacon from an alien civilization. The latest attempt to relocate the signal, reported in the January 10 issue of the Astrophysical Journal, was led by longtime SETI researcher Robert Gray with funding from The Planetary Society. But although Gray and his team used the entire Very Large Array in New Mexico, and although they detected many faint objects in the signal's general vicinity, they found no trace of an alien transmission. As of now, the "Wow" signal remains as enigmatic as ever..

[Jennie McGrath]

The Wow Signal
The computer printout of the "Wow!" signal, along with Jerry Ehman's famous comment. Credit: The Big Ear Observatory


The most famous signal in SETI history was detected on the night of August 15, 1977 at the Ohio State University Big Ear Observatory. As on every other night, while Big Ear was searching the skies for an alien signal, its observations were being recorded on a printout sheet. A long list of letters and numbers was continuously being churned out, one long string for every one of the fifty channels scanned by the telescope. A series of characters appeared recording an unusual transmission at the frequency of channel 2: "6EQUJ5" the list read. This startled Big Ear volunteer Jerry Ehman, a professor at Franklin University in Columbus, who was monitoring the readings that night. He circled the code for later reference and added a single comment in the margins" "Wow!" The signal entered SETI lore as the "Wow!" signal.

The series "6EQUJ5" described the strength of the received signal over a short time-span. In the system used at the time at Big Ear, each number from 1 to 9 represented the signal level above the background noise. In order to extend the scale, the staff added letters, with each one from A to Z representing increasingly stronger signal levels. 6EQUJ5 represented a signal that grew in strength to level "U," and then gradually subsides. In more familiar notation, the signal increased from zero to level 30 "sigmas" above the background noise, and then decreased again to zero, all in the span of 37 seconds.

Two aspects of this signal immediately caught the attention of Ehman and project director John Kraus, who saw the results the following morning. First of all, 37 seconds was precisely the time it takes the Big Ear scanning beam to survey a given point in the heavens. Because of this, any signal coming from space would follow precisely the "Wow!" signal's pattern - increasing and then decreasing over 37 seconds. This practically ruled out the possibility that the signal was the result of Earthly radio interference.

[Jennie McGrath]

Big Ear
The Big Ear Radio Telescope at Ohio State University, as it appeared before its demolition in 1998. Credit: The Big Ear Observatory

Secondly, the signal was not continuous, but intermittent. Kraus and Ehman knew that, because Big Ear has two separate beams that scan the same area of the sky in succession, several minutes apart. But the signal appeared on only one of the beams and not on the other, indicating that it had been "turned off" between the two scans. A strong, focused, and intermittent signal coming from outer space: could it be that Big Ear had detected an alien signal?

For a month following the discovery the Big Ear crew tried repeatedly to relocate the signal, but to no avail. In 1987 and again in 1989 Robert Gray led "Wow!" searches using the 84 foot radio telescope of the Planetary Society-funded META array at the Oak Ridge Observatory in Massachusetts, but found nothing. For his latest "Wow!" hunt Gray managed to secure the services of the entire Very Large Array in New Mexico, composed of twenty seven 25-meter dishes. This, according to Gray, was a first: "Contrary to popular belief since the movie Contact," he emphasizes, "the prestigious $80 million telescope hardly ever listens for broadcasts from the stars."

During two observing sessions in 1995 and 1996 Gray and his colleague, Kevin B. Marvel, used their telescope time to investigate several scenarios. One possibility was that the "Wow!" signal in fact represents a weak but steady transmission that momentarily gained in strength due to interstellar scintillation. The high sensitivity of the VLA guaranteed that such a source would be easily detected by Gray's survey. But despite identifying several radio sources hundreds of times weaker than the "Wow!" signal in the vicinity, nothing resembling a steady transmission was found.

[Jennie McGrath]

The Very Large Array (VLA)
The VLA is an NRAO (National Radio Astronomy Observatory) facility in the plains of St. Augustin, New Mexico. It is composed of 27 dishes, each 25 meters in diameter. Credit: NRAO

Another scenario assumed that "Wow!" was a brief powerful signal designed to attract attention to a weaker continuous one. Such a strategy would be more energy efficient than sending a continuous powerful beacon. But again, the VLA could detect no signal even 1000 times weaker than the original signal.


Finally there is the possibility that the signal is there, but is only broadcast intermittently. Because of their limited telescope time, Gray and Marvel could only devote less than an hour to any given position. It could be that the signal is on at other times, when no one is listening. The problem is in fact unavoidable from any location in the Northern Hemisphere, since the "Wow!" locale is below the Northern horizon during most of the day. To account for that possibility, Gray joined forces with Simon Ellingsen of the University of Tasmania, who will be able to track the area for 14 hours at a time.

To this day we do not know the source of the strongest and clearest signal ever to come through on a SETI search. Since it was undoubtedly artificial, and almost certainly of celestial origin, Jerry Kraus speculates that it may have come from a space probe (human space probe, that is…) that he and the Big Ear staff were not aware of. That would certainly make it an intelligent celestial signal, but not an alien one. And still, there is always the possibility that it was something else - a true signal from an alien civilization. Unless the signal is detected again, we may never know for sure.

To learn more about Robert Gray's search for the "Wow!" signal, see his article in the January/February 2001 issue of The Planetary Report.

http://www.planetary.org/news/2001/0117_The_Wow_Signal_Still_Eludes.html

[Jennie McGrath]

The "Wow!" Signal
By Barry Kawa

Jerry Ehman, the "Big Ear" volunteer who in 1977 saw one of the strongest signals ever detected, poses beside the radio telescope.

From the Cleveland Plain Dealer
Sunday Magazine section, September 18, 1994

As he had done a thousand times, Jerry Ehman glanced over the Big Ear's computer printouts, not really expecting to find anything unusual.

But what Ehman saw on that Aug. 15, 1977 - and his startled reaction - would be recorded in radio astronomy textbooks and discussed by researchers to this day.

The Columbus man saw a signal so strong that it catapulted the Big Ear's recording device off the chart. An excited Ehman scribbled "Wow!" on the printout, a tag that is indelibly linked to the recording.

"I mean, without thinking, I wrote 'Wow!' " Ehman recalls. "It was the most significant thing we had seen."

Could it be man's first contact with extraterrestrial intelligence? Ohio State University researchers weren't sure. They trained the massive scope on that part of the sky for the next month, and have returned periodically since.

The signal hasn't been recorded again. And although many point to it as a possible extraterrestrial intelligence sighting, Ehman remains less convinced.

"Even if it were intelligent beings sending a signal, they'd do it far more than once," Ehman, now 54, says. "We should have seen it again when we looked for it 50 times. Something suggests it was an Earth-bound signal that simply got reflected off a piece of space debris." [Note. In actuality, the number of observations at that declination and nearby declinations totaled just over 100.]

Ehman was working as a volunteer then. He had worked at OSU as an assistant professor in electrical engineering and astronomy, but when the National Science Foundation cut its funding to the Big Ear in 1972, Ehman was let go, although he stayed on on a volunteer basis.

He then worked as a professor at Franklin University in Columbus, until his retirement about a year ago [1993]. Ehman recently rejoined the Big Ear's volunteer staff.

Jerry Ehman

Now, Ehman is a mini-celebrity. Other volunteers ask him about the famous "Wow!" signal and it's often mentioned in the meetings. Journalists call him whenever they write about the Big Ear.

"I just wish when I talked to journalists, there was really something more to say about it. I'd like to say, 'Gee, that's a signal from extraterrestrial intelligence," Ehman says with a laugh. "I honestly can't do that."

Ehman's scientific training won't let him spin a good yarn. But, he says if the Big Ear staff could have detected the "Wow!" signal again, they might have been able to identify it.

So, until some listener is knocked off his seat again and the "Wow!" signal is rediscovered, Ehman's finding remains only a curious historical footnote.

"I can speculate, too, but there's nothing to back it up," Ehman adds.

http://www.bigear.org/wow.htm

[Majeston]

P371:7, 33:6.5
From Salvington, broadcasts are simultaneously directed to the constellation headquarters, the system headquarters, and to individual planets. All higher orders of celestial beings are able to utilize this service for communication with their fellows scattered throughout the universe. The universe broadcast is extended to all inhabited worlds regardless of their spiritual status. Planetary intercommunication is denied only those worlds under spiritual quarantine.

Constellation broadcasts are periodically sent out from the headquarters of the constellation by the chief of the Constellation Fathers.

The Urantia Book -- Part II. The Local Universe
PAPER 52: Section 7.
Post-Teacher Son Man


P599:1, 52:7.5
Life during this era is pleasant and profitable. Degeneracy and the antisocial end products of the long evolutionary struggle have been virtually obliterated. The length of life approaches five hundred Urantia years, and the reproductive rate of racial increase is intelligently controlled. An entirely new order of society has arrived. There are still great differences among mortals, but the state of society more nearly approaches the ideals of social brotherhood and spiritual equality. Representative government is vanishing, and the world is passing under the rule of individual self-control. The function of government is chiefly directed to collective tasks of social administration and economic co-ordination. The golden age is coming on apace; the temporal goal of the long and intense planetary evolutionary struggle is in sight. The reward of the ages is soon to be realized; the wisdom of the Gods is about to be manifested.

The physical administration of a world during this age requires about one hour each day on the part of every adult individual; that is, the equivalent of one Urantia hour. The planet is in close touch with universe affairs, and its people scan the latest broadcasts with the same keen interest you now manifest in the latest editions of your daily newspapers. These races are occupied with a thousand things of interest unknown on your world.




The Urantia Book -- Part II. The Local Universe
PAPER 46: Section 3.
The Jerusem Broadcasts
------------------------------------------------------------------------



P522:1, 46:3.1 The superuniverse and Paradise-Havona broadcasts are received on Jerusem in liaison with Salvington and by a technique involving the polar crystal, the sea of glass. In addition to provisions for the reception of these extra-Nebadon communications, there are three distinct groups of receiving stations. These separate but tricircular groups of stations are adjusted to the reception of broadcasts from the local worlds, from the constellation headquarters, and from the capital of the local universe. All these broadcasts are automatically displayed so as to be discernible by all types of beings present in the central broadcast amphitheater; of all preoccupations for an ascendant mortal on Jerusem, none is more engaging and engrossing than that of listening in on the never-ending stream of universe space reports.

P522:2, 46:3.2 This Jerusem broadcast-receiving station is encircled by an enormous amphitheater, constructed of scintillating materials largely unknown on Urantia and seating over five billion beings -- material and morontia -- besides accommodating innumerable spirit personalities. It is the favorite diversion for all Jerusem to spend their leisure at the broadcast station, there to learn of the welfare and state of the universe. And this is the only planetary activity which is not slowed down during the recession of light.

P522:3, 46:3.3 At this broadcast-receiving amphitheater the Salvington messages are coming in continuously. Near by, the Edentia word of the Most High Constellation Fathers is received at least once a day. Periodically the regular and special broadcasts of Uversa are relayed through Salvington, and when Paradise messages are in reception, the entire population is assembled around the sea of glass, and the Uversa friends add the reflectivity phenomena to the technique of the Paradise broadcast so that everything heard becomes visible. And it is in this manner that continual foretastes of advancing beauty and grandeur are afforded the mortal survivors as they journey inward on the eternal adventure.


P522:4, 46:3.4 The Jerusem sending station is located at the opposite pole of the sphere. All broadcasts to the individual worlds are relayed from the system capitals except the Michael messages, which sometimes go direct to their destinations over the archangels' circuit.