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How the 'Wow!' Signal Works


The Case Against the 'Wow!' Signal
The Very Large Array (VLA) is a set of 27 radio telescopes in New Mexico normally used for weather tracking and astronomical investigation. It was used to try and reproduce the 'Wow!' signal -- to no avail.
The Very Large Array (VLA) is a set of 27 radio telescopes in New Mexico normally used for weather tracking and astronomical investigation. It was used to try and reproduce the 'Wow!' signal -- to no avail.
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If you believe that we are not alone in the universe — or want to believe — then the "Wow!" signal offers thrilling proof that someone, somewhere, is trying to say "hello."

Then there's the bad news. In the more than three decades since Jerry Ehman circled the astonishing "6EQUJ5" on his printout, no SETI radio telescope has recorded anything like the "Wow!" signal. The Big Ear even scanned the same patch of sky 100 more times, but found nothing [source: Gray and Marvel].

Robert Gray, an amateur astronomer and data analyst with a passion for the "Wow!" signal, conducted the most serious attempt to replicate the signal using one of the biggest and baddest radio telescopes on Earth, the Very Large Array (VLA) in New Mexico.

In 1995 and 1996, Gray aimed the VLA at Sagittarius, the first time the telescope was used expressly to search for signs of extraterrestrial life. The VLA — which combines the power of 27 separate radio antennas — is 100 times more sensitive than the Big Ear, which was retired in 1997 [sources: NRAO, Gray and Marvel].

Sadly, Gray found no trace of the "Wow!" signal with the VLA. But that wasn't enough to convince him that the original recording was some kind of glitch [source: Gray and Marvel].

In a 2012 interview published in The Atlantic, Gray argued that our assumptions about extraterrestrial radio transmissions are all wrong. We imagine a constant beacon shining toward Earth from a distant planet. But the energy required to sustain such a broadcast — in all directions, at all times, across millions of light years — is equal to thousands upon thousands of our biggest power plants [source: Andersen].

What if the alien civilization isn't a hyper-advanced race with limitless resources, but something more like ourselves? The more economical approach would be to broadcast the signal from a type of radio "lighthouse" that transmits its message in only one direction at a time.

If that's the case, then our current system of searching for alien life — focusing on one patch of sky for 20 minutes before moving on to the next — would require tremendous luck to catch the signal as it briefly flashes our way [source: Andersen]. Our best hope, Gray believes, is to develop even more powerful and wide-ranging telescope technology that can scan the entire sky at once. Otherwise, we may never know if the "Wow!" signal was some kind of uncanny mistake or truly a "friend request" from far beyond.

For lots more information about SETI and unexplained space phenomena, check out the related HowStuffWorks links on the next page.


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