Alien life, or noise? Russian telescope detects 'strong signal' from sun-like star
Signal detected a year ago from HD164595, only 95 light years away and with at least one planet, but Seti scientists are scanning the area and have yet to find it
By: Sam Thielman
As David Bowie might have sung: is there life on HD164595b?
A Russian radio telescope scanning the skies has observed “a strong signal” from a nearby star, HD164595, in the constellation Hercules. The star is a scant 95 light years away and 99% of the size of Earth’s own sun. It has at least one planet, HD164595b, which is about the size of Neptune and has a 40-day year.
Seth Shostak of the Search for Extraterrestrial Intelligence Institute (Seti) in Mountain View, California, told the Guardian he was shocked to have learned of the discovery only now – the readings from Russian radio telescope Ratan-600, Shostak said, were taken a year ago.
Seti, a private organization, searches the skies for alien life and has been underwritten by US government divisions as diverse as Nasa and the Department of Energy. Operated by the Russian Academy of Sciences, Ratan-600’s primary area of focus is monitoring the sun, though it has contributed to Seti’s work.
The news came to international attention on Saturday through Claudio Maccone of the University of Turin in Italy, who attended a talk by the scientists who recorded the signal on 15 May 2015. Maccone passed data from the presentation to the science and science-fiction writer Paul Gilster, who maintains a blog about interstellar exploration called Centauri Dreams.
Maccone sent the Guardian his proposed presentation for the International Academy of Astronautics 2016 meeting on the subject of the search for alien life, set for 27 September. He will call for the permanent monitoring of HD164595. “The power of the signal received is not unrealistic for type I civilizations,” he wrote.
“Could it be an ET?” asked Shostak rhetorically. “Of course, but [Ratan-600] didn’t have a receiver that has any spectral resolution.” The receiver on the Russian radio telescope is very wide, which aids it in its primary mission of monitoring solar activity but also means that, like a terrestrial radio receiving a news station, rock’n’roll station and country station at the same time, it is difficult to discern which band is broadcasting at which frequency. “They have a receiver that would swallow a big chunk of the radio dial at once,” Shostak said.
Because the receiver covers such a big sweep of the radio dial, it is hard to tell if the signal comes from intelligent life.
If it is being broadcast across a large chunk of the radio spectrum, the noise is probably coming from a quasar or another source of stellar “noise”; if it is over a narrower band but very strong, it is likelier to be the product of intelligence.
Gilster said he was curious about the possibility that the signal could be caused by “microlensing” – a quirk of gravity that occurs when massive objects like stars or quasars are aligned behind another heavenly body.
“My own thought is that this is very possibly a one-time signal, much like the famous WOW! signal some years back,” Gilster said. On 15 August 1977, astronomer Jerry Ehman received a powerful radio signal from a group of stars called Chi Sagittarii; he circled the surprising spot on the readout and wrote “WOW!” The signal never returned.
“If it too doesn’t repeat,” said Gilster, “then we won’t know what it was, including the possibility of some kind of local signal whose source just hasn’t been figured out.”
Shostak said he wished he had been made aware of the signal earlier. “Why is it that we’re hearing about this now because one of the guys gave a talk in Moscow a year ago?” he asked. “Maccone’s explanation is that the Russians are ‘shy’. [But] it’s generally accepted procedure in the Seti community if you find a signal that you think is interesting, you call up people in another observatory and say: ‘Hey, here’s the position in the sky,’ and you see what happens.”
Gilster said his understanding was that the Russian team had spent the past year analyzing and confirming its data.
Shostak told the Guardian that Seti’s own radio telescope was scanning the coordinates in question in search of the promising signal as of Sunday night. That evening, though, everything was quiet.
The Russian radio telescope team and Maccone have been contacted for comment.
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