Scientists now say that it’s more likely than not a that an extraterrestrial civilization generated a signal from deep space detected in 1977.
Dr. Jerry Ehman first detected the 72-second “WOW!” signal with a radio telescope in August 1977. The signal was so bizarre that Ehman circled the signal on a readout and scribbled “Wow!” next to it, since it matched no known celestial object.
An April study published by Dr. Antonio Paris from St. Petersburg College in Florida found that the mysterious signal likely came from a hydrogen cloud surrounding a comet. Paris claimed to have debunked the WOW! signal, presenting findings indicating that an undiscovered comet produced a 1977 deep space radio signal.
However, several Search For Extraterrestrial Intelligence (SETI) astronomers announced Monday that they’re extremely skeptical of Paris’ explanation, because comets don’t emit radio waves in the right way to make the signal.
“We do not believe the two-comets theory can explain the Wow! signal,” Ehman told Live Science.
The original WOW! signal couldn’t be fully replicated by Paris because the signal appeared for such a short period of time that it didn’t repeat, even though the telescope was set up in a manner that would cause it do so.
“We should have seen the source come through twice in about 3 minutes: one response lasting 72 seconds and a second response for 72 seconds following within about a minute and a half,” Ehman said. “We didn’t see the second one.”
Ehman claims that the only way this could have happen was if the signal was cut off abruptly. A comet wouldn’t produce behave in this way, but an extraterrestrial intelligence could.
Scientists have long thought the WOW! signal was some of the strongest evidence of a technologically-advanced alien civilization. The signal was transmitted at a frequency that happens to be the same frequency as hydrogen. SETI scientists long suspected that an alien civilization would use that frequency to transmit its location since hydrogen is the most common element in the universe.
Scientists often speculate that mysterious signals from deep space could be from aliens, but the source is often found to be some unknown stellar phenomenon.
In 1967, for example, a graduate student in astronomy found an usual pulsing radio signal predictable enough to be a sign of intelligent life. Astronomers nicknamed the signal LGM-1, for “little green men.”
Some believed that they had detected a signal from an extraterrestrial civilization, but it turned out to be the first pulsar.