861998362

Photo by: Haitong Yu

Haitong Yu

The Wow Signal: No, It Wasn’t Aliens

On a typical muggy midwestern August evening in 1977, astronomers at the Ohio State University’s Big Ear radio telescope got a big surprise. It was a signal so loud that it could only be described with one word: “wow!”

December 10, 2020

Don’t believe me? That word was so important that the astronomer who was reviewing the data a few days later, Jerry R. Ehman, wrote it on the printout next to the signal.

Hence: The Wow! Signal.

In all respects, the signal really was remarkable. It lasted for only about 72 seconds, appearing to originate from somewhere in the direction of the constellation Sagittarius. It was thirty times stronger than the background radio hum of the rest of the sky. It was at a radio frequency forbidden from use by anyone on Earth, reserved purely for astronomical observations. It was nearly at a frequency that neutral hydrogen naturally emits.

It was never seen again.

Of course, it’s tempting to think of the Wow! Signal as a sign of an alien civilization trying to talk to us. And despite happening over 40 years ago, that mysterious radio blast is in the news again, this time as an amateur astronomer has used a catalog of stars to find a potential source of the signal.

The ESA’s Gaia mission has cataloged nearly a billion stars, planets, comets, asteroids, and quasars across the universe. And it turns out that one of those identified stars, 2MASS 19281982-2640123 (sorry about the long name but that’s all we’ve got), happened to be near the direction of the supposed origin of the Wow! Signal back in 1977.

So, What is 2MASS 19281982-2640123?

2MASS 19281982-2640123 is a pretty unremarkable star, which makes it interesting: it’s roughly the same mass, brightness, and age as our sun. Which means any planets orbiting it at the right distance could be a potential home for life. Which means any intelligent critters living on one of those planets could have sent the Wow! Signal in our direction.

The trouble with this news story (and the Wow! Signal in general) is that it’s so tempting to jump on the alien hypothesis that it’s easy to start ignoring other possibilities. The astronomer behind the latest study only looked for sun-like stars in the Gaia data and skipped over any other possible source. So naturally there’s going to be a juicy news story here, rather than something much less engaging.

The biggest problem when trying to connect the Wow! Signal to aliens is that it’s never happened again–ever. Multiple searches with multiple telescopes over multiple decades have never seen the same signal repeated, in that patch of the sky or anywhere else. If it was aliens trying to contact us, it was the ultimate cosmic butt-dial: they rang once but never followed through.

Still a Mystery

652232226

Photo by: Haitong Yu

Haitong Yu

Ultimately, we’re not exactly sure what caused the Wow! Signal. Observations of 2MASS 19281982-2640123 have revealed that it’s…just another sun-like star in the galaxy, doing nothing interesting or out of the ordinary. The Wow! Signal could have terrestrial origins (people have broken the rules of radio before, after all), it could have been a fluke in the telescope system (which happens all the time), or it could be some flash of crazy physics in the universe (which happens all the time too). Either way, it’s likely that we’ll never know.

Hey, it’s good to have a few mysteries left in the universe, right?

Paul M. Sutter

Paul M. Sutter is an astrophysicist at Stony Brook University and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of How to Die in Space.

Next Up

The Nobel Prize Fell Into a Black Hole (and That’s a Good Thing)

The 2020 Nobel Prize in Physics is being awarded to scientists to have dedicated their careers to the study of black holes.

When We’ll Know if NASA’s Asteroid Impact Test was a Success

Recently NASA’s DART mission succeeded in its primary goal, which was to slam a spacecraft face-first into an asteroid. For science. The intention of the mission was to test if we could actually redirect an asteroid and send it into a different orbit. But how and when will we know if it worked?

What Screaming Black Holes are Telling Us

In 2002, NASA’s orbiting X-ray observatory, the Chandra telescope, mapped out the movements of hot gas in a cluster of galaxies sitting 250 million light-years away.

Want to Name a Planet? Now’s Your Chance

Read on to learn about this rare opportunity to name a distant world observed by the James Webb Telescope.

Watch NASA's Asteroid-Crashing DART Mission Make Impact

NASA sent a spacecraft on a mission to crash into an asteroid, so how did it go?Updated 9/26/22

Watch Out! Amateur Astronomer Watches as Jupiter Gets Whacked

Jupiter is the OG best friend in the solar system. It finds all the tiny little comets and asteroids heading for the vulnerable inner planets and takes one for the team, chewing up the dangerous rocks in its thick atmosphere. It happened again just recently, and this time an amateur astronomer caught it in the act.

Astronomers May Have Found a Rare “Free-Floating” Black Hole

How do you see a perfectly black object in the middle of a pitch-dark night? It sounds like the start of an annoying riddle, but it’s really the question faced by astronomers when they want to search for black holes.

Six Planets are Retrograde, What Does that Mean for You?

Spoiler alert: It's an optical illusion.

NASA Has a New Supersonic Jet and It’s Super-Quiet

There’s more to NASA than space. The agency’s full acronym stands for National Aeronautics and Space Administration. I’ve covered plenty of interesting stories in the space sector, so it’s time to the aeronautics side some love too.

NASA’s $10 Billion Space Telescope Hit by Micrometeoroid

NASA’s new James Webb Space Telescope (JWST) was recently hit by a micrometeoroid. One of the 18 golden mirror segments on the telescope was hit, causing some minor damage.

Related To: