The Wow! Signal: The 72-Second Radio Burst We've Never Heard Again
Answers: “what was the wow signal from space?”
On the night of August 15, 1977, a radio telescope in Ohio called Big Ear was doing what it did every night — quietly sweeping the sky for anything unusual.
At 10:16 p.m., something unusual arrived.
A narrowband radio signal, 30 times louder than the background noise of deep space, poured in from the direction of the constellation Sagittarius. It lasted the full 72 seconds the telescope could observe that patch of sky — exactly the profile you’d expect from a source out in space, not interference from Earth.
Days later, astronomer Jerry Ehman was reviewing the printout. When he saw the sequence — the now-famous characters 6EQUJ5, a code for the signal’s rising and falling intensity — he grabbed a red pen, circled it, and wrote a single word in the margin:
“Wow!”
Here’s what makes the signal genuinely strange, not just good campfire material:
- It arrived at 1420 MHz — the frequency emitted by hydrogen, the most common element in the universe. SETI scientists had long predicted that if a civilization wanted to hail others, this is the “universal channel” they’d use.
- That frequency is protected on Earth — no aircraft, satellite, or station is permitted to broadcast there.
- Every natural explanation proposed since — comets, satellites, reflections — has been challenged or debunked.
Astronomers have pointed telescopes at that patch of sky over 100 times since 1977.
Silence. Every time.
The Wow! signal remains what it was that August night: the single strongest candidate for an extraterrestrial transmission ever recorded — heard once, and never again.