Welcome to a special A to Z Challenge edition of Sciency Words! Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms. In today’s post, W is for:
THE WOW! SIGNAL
There’s a ton of radio noise in space, coming from stars and nebulae and black holes and so forth. There’s so much radio noise that it can easily drown out the relatively weak radio and television broadcasts that might be coming from a planet like Earth.
So if aliens want to talk to us, they’re going to have to send a much stronger transmission, something that will come through loud and clear over all that other space noise. And in 1977, astronomers at Ohio State University picked up exactly that kind of signal.
As the story goes, Ohio State was conducting a SETI search with their “Big Ear” radio telescope. The telescope recorded electromagnetic emissions coming from space, reporting the strength of those emissions on a scale from 0 to 9. If Big Ear happened to pick up anything stronger than a 9, it represented that with a letter—A represented a 10, B represented 11, and so forth.
On the morning of August 18, 1977, astronomer Jerry Ehman was reviewing Big Ear’s latest data when he saw a bunch of large numbers, and even a few letters. Famously, Ehman circled those letters and numbers and wrote one word next to them: Wow!
Appropriately, this is now known as “the Wow! Signal” (the exclamation point is usually included in the name).
In one sense, the Wow! Signal is exactly what SETI scientists were hoping to find. Even the radio frequency—approximately 1420 megahertz—was consistent with expectations. In this 1959 paper, physicists Giuseppi Cocconi and Philip Morrison singled out 1420 MHz as the frequency extraterrestrials were most likely to use.
But in another sense, the Wow! Signal was not what we wanted it to be, because it only happened one time, and it has never repeated since. Despite many follow-up searches of the constellation Sagittarius (like this one or this one), where the Wow! Signal originated from, we’ve never picked up a signal like it again.
As I’ve said several times this month, in our search for alien life, we have to hold ourselves to the same standards as a court of law: proof beyond a reasonable doubt. The Wow! Signal very well might have been aliens… it might have been anything… and that’s the problem. Unless and until we pick up the Wow! Signal again, we can’t prove one way of another what it was.
Next time on Sciency Words A to Z, you can’t have life without water. Or can you?