Science -> Homeclick!
Cette page en franšaisCliquez!

Science and the UFO Phenomenon:

SETI efforts:

There are scientists searching for extra-terrestrial intelligent life in the Universe. Most of them have not searched or studied the UFO phenomenon and think it is not a valid scientific problem. I have gathered here under the title "SETI efforts" some information about their research of extra-terrestrial intelligence outside our solar system.

Note: scientific investigation of the UFO problem as a certain or possible or impossible manifestation of extra-terrestrial intelligence on Earth and within the solar system is presented and discussed in the Science section of my site.

SETI project and the "Wow!" signal:

On the night of August 15, 1977 at the Ohio State University, a signal was detected from the Big Ear Observatory. Big Ear was searching the skies for an alien signal as for every night, and its observations were coming out on a printer as a long list of letters and numbers, one long string for every one of the fifty channels scanned by the radiotelescope.

A series of characters appeared recording an unusual transmission at the frequency of channel 2: "6EQUJ5." This startled Jerry Ehman, a professor at Franklin University in Columbus, who was monitoring the readings that night as Big Ear volunteer. 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.

SETI specialists explain this transmission of "6EQUJ5" like this:

"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."

An aspect of this signal immediately caught the attention of Ehman and project director John Kraus when they saw the results the following morning: 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 this 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.

Then they noted that the signal was 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. So they had a strong, focused, and intermittent signal coming from outer space, and could start to wonder if Big Ear had detected an alien signal.

For a month, the Big Ear crew tried repeatedly to relocate the signal, but in vain. In 1987 and again in 1989 Robert Gray led "Wow!" searches using the 84 feet radio telescope of the Planetary Society-funded META array at the Oak Ridge Observatory in Massachusetts, and also 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.

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.

Another possibility pointed out by SETI scientists is 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.

In 1997, the lease under which the Big Ear radio telescope operated expired. The telescope, once home to the world's longest running SETI program (it began in 1974), was demolished to make way for a commercial golf course.

Robert S. Dixon, the observatory's assistant director, stated:

"It is a tragic commentary on the value judgments of our society to see humankind's longest search for their brethren in the universe forced to stop."

The SETI League later saved pieces of the Big Ear telescope, small pieces of the metal mesh which once covered the surface of the antenna, and sold them to raise funds for the search, mounted on a wooden plaque for public display, along with a depiction of the "Wow!" signal, and the advertising comment "These sections of antenna reflector were actually illuminated by the famous signal."

On the 20th anniversary of the detection of the signal, SETI celebrated the event, with comments such as:

"On August 15, 1977, OSU's "Big Ear" radio telescope detected the most famous, and intriguing, candidate signal to date in the search for signals from other worlds. The so-called "Wow!" signal (which was featured in the TV program "The X-Files") never repeated, and has never been explained."

Since Congress terminated NASA's SETI funding in 1993, the Planetary Society, the SETI League and other scientific groups have been attempting to privatize the research, with limited success.

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.

In the Press:

The event was covered in many newspaper around the world. Here is an article from the US newspaper Cleveland Plain Dealer, Sunday Magazine section, September 18, 1994.

The "Wow!" Signal

By Barry Kawa.

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."

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 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.

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.

Since then, sometimes possibly interesting signals are mentionned, with no follow-up.

Valid XHTML 1.0 Strict



 Feedback  |  Top  |  Back  |  Forward  |  Map  |  List |  Home
This page was last updated on March 10, 2004.