The WOW! Signal

One summer night in 1977, Jerry Ehman, a volunteer for SETI, or the Search for Extraterrestrial Intelligence, may have become the first man ever to receive an intentional message from an alien world. Ehman was scanning radio waves from deep space, hoping to randomly come across a signal that intelligent aliens might send when he saw his measurements spike.

The signal lasted for 72 seconds, the longest period of time it could possibly be measured. It was loud, most probably transmitted from a place no human has gone before: in the constellation of Sagittarius near a star called Tau Sagittarii, 120 light-years away. Ehman wrote the word “WOW!” on the original printout of the signal, thus its title as the “WOW! Signal.”

From the moment Ehman red-penned in “WOW!”, this has been known as the WOW Signal, and it’s been the cause of much speculation by SETI researchers and alien fans. Millions of people have discussed whether it could be a cryptic message from an alien civilization and what it might mean.

Unfortunately, all attempts to locate the signal again have failed. It left a mystery about its origins and meaning. Recently, some scientists have suggested the signal might have been a then-unidentified comet. Just for fun: In 2012, researchers used the Arecibo Observatory in Puerto Rico to send a signal from Earth containing messages, tweets and photos in the direction that the WOW Signal originated from.