On 15 August 1977, the Big Ear telescope in Ohio picked up a 72-second burst of radio waves from the direction of Sagittarius. Astronomer Jerry Ehman circled it on the printout and wrote "Wow!". It has never been heard again.
Truth label: Established. Strong evidence and broad agreement among experts.
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Why it stood out
It was narrow, strong and close to a frequency hydrogen gives off naturally, one scientists expected aliens might use.
A natural answer?
A 2024 study suggested a cold hydrogen cloud briefly brightened by a passing star. It remains a possibility, not a solution.
Learn
- Why one signal is not enough. Science needs repeats. Searches have returned to the same patch of sky many times with no luck.
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How long did the Wow! signal last?
72 seconds. The telescope swept past the source in about 72 seconds.
Sources
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