A new study has re-examined the famous "Wow!" signal, finding that it likely has an extraterrestrial origin after all, and may have been even more intense than previously believed.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.
On August 15, 1977, at the Big Ear radio telescope observatory at Ohio State University, a narrowband radio signal was received. A few days later, astronomer Jerry Ehman reviewed the data and noticed the signal sequence, which lasted for a full 72 seconds. In the margin next to the printout, he simply wrote "Wow!", and thus the puzzling signal had a name that would stick for the next 43 years at least.
The signal has, so far, defied explanation, and that's not for a lack of trying. Researchers argued the case for it being a comet passing through the area Big Ear was listening to, only for that to be completely refuted about two days later by the team that detected the Wow! signal in the first place, as a comet would have produced a diffuse signal given the large area they cover, rather than the abruptly cut-off signal that was received.
The signal has been a source of speculation in the "aliens are out there" community, and not without reason. No other signal like it has been detected before or since. It was in a range of frequencies close to the hydrogen line, which is relatively free from background noise, making it a good range to pick were we to try and communicate with other civilizations ourselves. On top of that, the team themselves believed it to be a good candidate for extraterrestrial life.
"The 'Wow!' signal is highly suggestive of extraterrestrial intelligent origin," Ohio State University Radio Observatory director John Kraus wrote in a letter to Carl Sagan in 1994, "but little more can be said until it returns for further study."
Since then, the signal has been the subject of many studies, but it has never returned. In a new attempt to narrow down what it might be, a team of scientists re-analyzed decades of data from the Big Ear telescope using modern signal analysis techniques, as well as analyzing data which had previously been unpublished, producing two not as yet peer-reviewed papers on the topic.
First up, the team found that the signal was very unlikely to have been the result of interference in the telescope itself, or of terrestrial origin. The team found strong statistical evidence that the signal was not the result of radio frequency interference (RFI).
"If this RFI is persistent, it would take approximately six millennia of uninterrupted observations to achieve a signal analogous to the Wow! Signal from random RFI occurrences," the team explains in paper II.
Looking at other possible sources, including satellites, the team found this to be unlikely as well. Most satellites of the time were not in the area of the sky identified by the team, orbiting on different planes. While the team suggested that satellites which have slowly come out of orbit could be a source, or a Soviet satellite occupying this orbit, they believe this is unlikely too. This is because they would spend only a few fractions of a second in front of the telescope, rather than the 72 seconds necessary to replicate the Wow! signal.
... continue reading