It’s old news, but it bears repeating from time to time. The Wow! Signal is a radio signal detected during a SETI scan in 1977. Its name derives from SETI volunteer Jerry Ehman’s written marginal comment on the computer printout when he first reviewed the data. The evidence of the signal is a sequence of six values reflecting a powerful signal in a very narrow frequency band over a period of approximately 72 seconds (the time the particular section of sky was in the bull’s eye of the Ohio dish that received the signal).
The sequence of values reflected scaled intensity displayed on the 1977 printout as 6, E, Q, U, J and 5, where two-digit values (values above 9) are represented by letters, beginning with A as 10, B as 11, and so on. The start of the signal was 6–a strong burst in its own right. As time passed, the signal strength increased, topping out at U, a signal about 30 times stronger than the ordinary noise of deep space.
Dr. Ehman’s “Wow!” notation appears to have been appropriate.
The signal is particularly interesting because it looks just like what many thought would be the best reasonable signal of intelligent origin that SETI could detect–it was in the narrow hydrogen band range, it was short, it did not correlate to any phenomenon that would otherwise explain the signal (i.e., no natural source) and it bears no characteristics that would match a stray human-originated signal. Even its absence from detection later is consistent with expected results, and not unlike deliberate signals from Earth like the three-minute blast of the Arecibo message in 1974.
Because of technical limitations (this was 1977, well before the PC found its way into modern homes), only a signal-to-noise-ratio intensity could be measured over 12-second intervals. No details were recorded. So if it said anything, we don’t know what it was. We only know how loud it was.
The precise origin of the signal cannot be determined. In fact, since the Big Ear antenna that received the signal had two horns, and we don’t which of those two horns fed the signal in (remember, 1977), we can’t even determine which of two “general” areas may have initiated it. We do know it was somewhere in the area of Sagittarius in one of the two regions illustrated below.
The event is well documented. Wikipedia is as good a place as any to start. http://en.wikipedia.org/wiki/Wow!_signal. It is not proof of an intelligent, deliberate extra-terrestrial signal. But it is evidence. The lack of further evidence plays prominantly in my nearly finished work in progress.