Buzz is growing over the possibility of intelligent alien life, thanks to a group of Russian astronomers who say they’ve picked up a strong mysterious radio signal from space. The potential source of the signal is exciting: it seems to be coming from a distant system with a Sun-like star. Perhaps this star has a civilization-filled planet just like ours, right? Well before you assume we’ve found ET’s home, consider this: astronomers still need to find another signal coming from the same spot in the sky — and that may not be likely.
Don't assume we've found ET's home
The astronomers picked up the original signal using the RATAN-600 radio telescope, a large radio observatory in Zelenchukskaya, in southwestern Russia. Their data indicates that the signal came from the direction of a star called HD164595, located 95 light-years from Earth. That’s intriguing since the star is about the size of the Sun, and it’s known to have a planet in its orbit. Granted, that planet orbits much closer to its star than Mercury orbits the Sun, so it’s probably way too toasty to support life. But it’s possible that there are other planets in this system we just don’t know about yet.
Still, Seth Shostak, the director for the Center for SETI Research, cautions people to curb their enthusiasm. There are many different possible explanations for what caused the detection, and until a repeat signal is picked up from the same spot in the sky, no one can cry "alien." Signals like this have also been picked up a few times before, and none has yet to pan out. "I would say it’s a mystery signal, but mystery signals are not new," Shostak told The Verge.
The signal picked up by the Russians isn’t all that new, either. Astronomers actually found it a year ago, but it’s making headlines now for a few reasons. A member of the research team emailed out a presentation about evidence of the signal to a few people, and then Paul Gilster, a science and tech writer, wrote about the signal on his website Centauri Dreams. "The possibility of noise of one form or another cannot be ruled out," wrote Gilster. "But the signal is provocative enough that the RATAN-600 researchers are calling for permanent monitoring of this target."
The RATAN-600 radio telescope. (Russian Academy of Sciences)
The fact that the Russian astronomers waited so long to tell the SETI — search for extraterrestrial intelligence — community about the signal is a little odd, said Shostak. "It’s generally accepted if you find a signal you think might conceivably be due to extraterrestrial activity, you’d want to confirm it with someone looking at it with another antenna," he said. Now, it’s going to be hard to confirm what the RATAN-600 picked up last year was authentic. And finding a repeat signal this long after the original detection seems unlikely. Perhaps the signal was repeating back when it was first found, but isn’t any longer.
It’s not clear what the signal actually was
Also it’s not clear what the signal actually was. The receiver the Russians used was set at a wide bandwidth, making it difficult to decipher the signal’s source, according to Shostak. It’s possible it was a message from another civilization or just the effect of a natural space object, like a pulsating quasar. Not knowing the source of the signal makes it hard to tune into the same signal again.
And it’s highly likely the signal didn't even come from space. The Russian Academy of Sciences conducted its own analysis of the signal and determined it was likely caused by radio interference here on Earth: "Under this program, in 2015 on one of the objects (the star HD164595 system in the constellation of Hercules), was detected interesting radio signal at a wavelength of 2.7 cm. Processing and signal analysis revealed that the most likely, it's still a signal of terrestrial origin."
Despite this, Shostak and his team are still taking a good look at HD164595. Over the weekend, they fired up the Allen Telescope Array — a large collection of radio telescopes northeast of San Francisco — and pointed it in the direction of the star. So far, it’s been radio silence, and Shostak isn’t holding his breath for anything more. The Allen Telescope Array isn’t as big as the RATAN-600 Radio Telescope, so it may not be powerful enough to pick up what the Russian astronomers found. Also, Shostak said it’s not really clear the point in the sky where the original signal came from. Due to the design of the RATAN-600, the astronomers only know the general area of the signal’s origin. "It’s not even clear that this signal is coming from that star system," said Shostak.
Plus, any potential civilization in the HD164595 system would need a lot of power to broadcast a signal like this. If the signal was broadcast in all directions, then it’d have to be powered by 10 billion billion watts, according to Shostak. "Maybe the aliens have access to that kind of energy, but we sure don’t," he said. Less power would be needed if for some reason the signal was focused directly at Earth. But the power would be comparable to all the energy that humanity uses — including all our transportation, all our electronics, and all our power plants.
"If you don’t find [these signals] a second time, they’re not that interesting."
But above all, SETI researchers have been burned by mysteriously strong space signals before. The most famous example was the so-called "Wow signal" — a strong radio signal picked up by astronomers at Ohio State University in 1977. One of the astronomers was so enthusiastic about the signal’s strength that he wrote the word "Wow!" on a computer printout of the data. As exciting as that signal was, though, it has yet to be detected again.
So until another signal is found coming from the HD164595 system, the discovery in no way indicates aliens. "If you don’t find [these signals] a second time, they’re not that interesting," said Shostak. "It could be terrestrial interference, a bug in the system, or it could be a natural source... I’m not terribly excited about it, because these kinds of things have happened a lot in the past."
Update August 31st 10AM ET: This article was updated to include a statement from the Russian Academy of Sciences.