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SETI Investigating Signal From Sun-Like Star 95 Light-Years Away

The frequency of the signal, first detected in May 2015, is unlikely to be an astrophysical phenomenon. But scientists have yet to rule out terrestrial interference.

ByTim De ChantNOVA NextNOVA Next
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The Allen Telescope Array, one of the telescopes now observing HD 164595.

Over the weekend, astronomers trained their telescopes a relatively close star, hoping for more evidence of a curious signal heard over a year ago by Russian radio telescope operators.

First detected on May 15, 2015—but only just now reported to other SETI scientists—the 11 GHz signal appears to have originated from HD 164595, a star with 0.99 solar masses and known to have at least one planet orbiting it, a so-called “warm Neptune.”

The frequency of the signal is unlikely to be an astrophysical phenomenon, though scientists have yet to rule out terrestrial interference.

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Here’s Alan Boyle, reporting for GeekWire:

At least two SETI research groups are aiming to track HD 164595 tonight. The SETI Institute is using the Allen Telescope Array in northern California, while METI International is looking to the Boquete Optical SETI Observatory in Panama.

[Centuari Dreams’ author Paul] Gilster reports that the signal spike was detected more than a year ago, on May 15, 2015, by the RATAN-600 radio telescope in Zelenchukskaya. That facility is in the Russian republic of Karachay-Cherkessia, not far from the Georgian border.

Doug Vakoch, president of METI International, a SETI-affiliated group, expressed dismay in an email to Boyle that the report took so long to make its way to other scientists, saying that quick communication can help confirm the source or rule out interference. Vakoch’s team is among those now observing the star.

The high frequency is what’s driving interest in the signal. Here’s Eric Berger, reporting for Ars Technica:

“If this were a real astronomical source, it would be rather strange,” [astronomer Nick] Suntzeff told Ars. Although there are mysterious, high-energy astrophysical phenomenon called “fast radio bursts” that are seen at a few gigahertz, they last only 10 milliseconds or so (this event lasted longer). Unfortunately, he said, there is no information given about the strength of the signal as a function of frequency.

It’s possible that an 11 GHz radio signal could be ground-to-satellite communication or some unknown military transmission.

For now, given the number of caveats attached to this signal, astronomers are downplaying the possibility of extraterrestrial life.

We are on the verge of answering one of the greatest questions in history: Are we alone?

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Photo credit: Seth Shostak/SETI/NSF