What is this mysterious radio signal from space?

Russian researchers' detection of a signal from the vicinity of the sun-like star HD 164595 has prompted plenty of speculation, although the possibility that it was sent from intelligent life is slim.

Ben Margot/AP/File
Radio telescopes of the Allen Telescope Array are seen in Hat Creek, Calif., Oct. 9, 2007. Dozens of the SETI radio dishes that make up the Allen Telescope Array in the mountains of far Northern California have scanned deep space since 2007 for alien signals.

Finding signs of intelligent life beyond Earth has been a dream of many scientists and science fiction enthusiasts for decades. So since news hit this weekend that a team of Russian astronomers received a mysterious radio signal from space, speculation on the origin of the signal has run rampant.

Is it aliens? Don't count on it. But the strength and nature of the signal are unusual enough that scientists are not ruling out many possibilities.

"Without a confirmation of this signal, we can only say that it's 'interesting,'" Seth Shostak, a senior astronomer at the SETI Institute, wrote in a blog post.

The signal was detected in May 2015 by the RATAN-600 radio telescope in Zelenchukskaya, Russia, not far from the Georgian border of the country, and researchers determined it seems to have come from the vicinity of HD 164595, a star about 94 light-years away.

It is possible that the signal was a fluke caused by some local radio transmission or a natural stellar phenomenon, which has turned out to be the case several times during prior "alien signal" detections. Still, the radio signal was striking enough for the RATAN-600 team to call for permanent monitoring of HD 164595, according to Centauri Dreams, a blog that monitors research related to interstellar exploration.

As it happens, a little is already known about that distant solar system. HD 164595's central star is about the same size and brightness of our sun, though it is a few billion years older. Astronomers have identified one Neptune-sized planet orbiting its sun: too close to support life as we would know it, but there may be other unidentified planets orbiting the star, according to the SETI Institute.

It is possible, however, that researchers could be a little off on the origin of the signal, due to some unusual aspects of the signal's detection. The radio telescope that received the transmission has a bandwidth a great deal larger than extraterrestrial radio detectors usually receive, making it difficult to pin down the exact location of the source.

"Just as a pot pie, incorporating lots of ingredients, can make guessing the individual foodstuffs more difficult, a wide-bandwidth receiver can dilute the strength of relatively strong narrow-band signals," Dr. Shostak writes. SETI's Allen Telescope Array, based in northern California, has now swung in the direction of HD 164595 to see if it can pick up a repeat transmission. 

It is unlikely that the signal came from intelligent life, astronomers say; it's merely one of several possibilities that can't yet be ruled out. But if it did, the nature of the signal would have some exciting implications as to what kind of civilization they would be.

A general transmission from HD 164595, sent out in all directions, would have had required 1020  watts to transmit: 100 billion billion watts. If Earth was being targeted, specifically, the energy cost would decrease, but still be more than a trillion watts. That scenario seems unlikely since Earth's own radio and TV transmissions have not arrived at HD 164595 yet, given the distance.

And 100 billion billion watts "is hundreds of times more than all the sunlight falling on Earth," Dr. Shostak told Space.com. "That's a very big energy bill." If aliens did send a transmission from HD 164595, it would require a civilization with energy technology far more advanced than anything that humans have ever developed, as Paul Gilster notes for Centauri Dreams. 

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.