A Science Mystery – What is the Wow! Signal?

(Last Updated On: June 1, 2018)

Wow! Signal

E.T., Can You Hear Me Now?

1977 was a good year for those interested in the search for extraterrestrial life. No, it wasn’t because ‘Star Wars’ and ‘Close Encounters of the Third Kind’ were both released that year. Rather, it was the Wow! Signal that captured the imagination of scientists and stargazers alike.

Scientists have long hypothesized how alien civilizations might communicate with others in the universe. In the 1960s, a couple scientists theorized that radio signals could be used for interstellar communication. Radio transmissions require little energy to generate and can travel large distances across space. It wasn’t long before scientists began to open their ears to the cosmos.    

In 1977, a volunteer astronomer named Jerry Ehman was using Ohio Wesleyan University’s Big Ear radio telescope (which was torn down in 1998) as part of Ohio State’s participation in the SETI project. He was searching for radio signals from deep space. In those days, data from the telescope was run through a computer and printed out. Results were tediously examined by hand. While reviewing the results from a few days earlier, he noticed something astonishing.

On the printout was a vertical column with the alphanumerical sequence ‘6EQUJ5’. This had occurred at 10:16 p.m. on August 15th, when he was pointing the telescope towards the constellation Sagittarius. He circled the sequence and wrote ‘Wow!’ in the margin of the readout.

The signal seemed to be exactly what Ehman had been looking for. Two of his colleagues examined the data and were equally amazed. Each digit on the printout represented the intensity of a radio signal, with intensities over nine being represented by letters. Most of the time, printouts only had ones and twos, or low intensity signals. Ehman’s readout suggested an extremely powerful signal – about 30 times greater than the ordinary ambient noise of deep space.

The blast was the loudest, longest signal that the Big Ear would ever pick up.

So Aliens Exist, Right?

Well, not so fast.

The Wow! Signal remains the first and best potential evidence of communication from extraterrestrials. Over the years, Ehman and his colleagues have worked to rule out other explanations, like satellites, aircrafts, or ground-based transmitters on Earth. Still, some questions remain.

For one thing, no one has ever been able to actually prove the signal was indeed a message. Scientists have traced the signal to a spot in space that lacks a star or planet. This seems to be an unlikely origin for a deep space alien message.  

Furthermore, sending a message of that magnitude would require a transmitter vastly more powerful than anything on Earth. That’s not to say an alien species couldn’t have invented such technology, but skeptics wonder why an alien civilization so advanced would never try to make contact once more. Despite lasting for 72 seconds, the signal was never detected again.

Recently, some have further questioned the legitimacy of the Wow! Signal. Professor Antonio Paris of St Petersburg College, Florida has hypothesized that the signal was caused by two passing comets. However, this hypothesis has also drawn its share of skepticism.

Today, the Wow! Signal lives on as one of the great mysteries of science. Whatever the cause, there is no denying that something made that frequency. Whether or not it was aliens is something scientists will have to continue to investigate. If it is extraterrestrial beings trying to make contact, let’s just hope their message was friendly.

About the Author:

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Mark Heald is the Managing Editor of Sporcle.com. He enjoys spending time with his family, traveling, and bemoaning the fact the Sonics left Seattle.