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What is the Wow! signal?

Q: What is the Wow! signal?

The Wow! signal was a powerful, narrow-band radio burst detected by Ohio State University’s Big Ear telescope on August 15, 1977; its beam-shaped rise and fall suggested a fixed celestial source, and Jerry Ehman’s handwritten “Wow!” gave it its name. SETI researchers regard it as a compelling but unconfirmed candidate for an extraterrestrial transmission, while other astronomers favor rare natural explanations involving hydrogen and transient cosmic activity. It lasted about 72 seconds and never recurred, leaving its origin unresolved.

Type: Background entry
Sources: 8

The Wow! signal was an extraterrestrial beacon aimed at Earth rather than a natural radio flare.

Summary

The strongest established account treats the Wow! signal as a genuine, exceptionally intense narrow-band radio event with characteristics that made an artificial source plausible. Its celestial beam profile and frequency were striking, but the absence of recurrence prevents confirmation as an extraterrestrial transmission. The mainstream position therefore preserves the anomaly without treating it as proof of alien intelligence.

The signal matched several criteria SETI uses to identify potentially artificial transmissions: narrow bandwidth, high intensity, and a profile consistent with a celestial source crossing the beam.
Its frequency and short duration made the event unusually compelling as a candidate extraterrestrial transmission.
Non-recurrence is the central evidentiary limitation: follow-up searches found no repeat signal.

Source mix

2 of 8 institutional

2 Journals & institutions
3 News reporting
1 Reference & archives
2 Other / unclassified

Deeper Insight

The Wow! signal lasted 72 seconds, then vanished. One fleeting clue can keep the universe mysterious without making it meaningless.

On August 15, 1977, Big Ear caught a narrow-band burst that rose and fell like a celestial beacon. Jerry Ehman wrote “Wow!” beside the reading, and the name stuck. It never returned, never formed a message, and still sits between alien transmission and rare natural event. Sometimes the missing repeat is the mystery.

What it could changeA repeat signal would turn one strange reading into evidence of a source we could study.
How it touches todayAstronomers still have to build knowledge from events that happen once and leave no second chance.
Our futureWe could spend generations chasing a cosmic clue that never gives us enough to close the case.

One proposal attributed the signal to hydrogen clouds associated with comets 266P/Christensen or 335P/Gibbs, but astronomers raised substantial objections to that explanation.
A newer hypothesis proposes that a powerful transient cosmic outburst struck a hydrogen cloud, producing a brief radio flare that mimicked an artificial signal.
Similar radio signals and reanalysis have strengthened the case for a natural source, but researchers still dispute whether the evidence is decisive.

Sources · 8

2 Journals & institutions
3 News reporting
1 Reference & archives
2 Other / unclassified

What do these mean?

Journals & institutions. Published in a peer-reviewed journal, or from a university, government body, court or other institution.
News reporting. Journalism: newspapers, magazines and news sites.
Reference & archives. Encyclopedias and web archives: a place to look something up or a stored copy, not an original source.
Other / unclassified. A site we have not classified yet. This says nothing good or bad about it.

Featured · Analysis · seti.org
The Wow Signal
Institution
The Wow Signal ## At a Glance: The Wow! Signal (SETI 101 — SETI Institute) - What: A strong, narrow-band radio signal (print-out sequence “6EQUJ5”) detected on Monday, August 15, 1977 by the Ohio State Radio Observatory (operated by Ohio State University) during a routine sky survey. - Where: The ob
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Analysis · nationalgeographic.com
Was the 'Wow!’ signal a message from aliens? | National Geographic
News reporting
Was the 'Wow!’ signal a message from aliens? | National Geographic # This mysterious radio signal has puzzled astronomers for nearly 50 years The “Wow!” signal is one of our best pieces of evidence for aliens, but researchers are building a compelling case for a more natural source. In a series of p
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Analysis · scientificamerican.com
The Wow! Signal SETI Mystery Might at Last Be Solved | Scientific American
News reporting
The Wow! Signal SETI Mystery Might at Last Be Solved | Scientific American August 21, 2024 The Wow! Signal Might Not Have Been Aliens—But a Weird Cosmic Outburst A new explanation for the Wow! signal suggests it was a chance detection of a furious flare crashing into a hydrogen cloud. But some resea
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