Russian astronomers acknowledge that they picked up an “interesting radio signal” in the course of their search for alien transmissions, but that the signal was most probably a case of terrestrial interference.
“It can be said with confidence that no sought-for signal has been detected yet,” astronomers from the Special Astrophysical Observatory of the Russian Academy of Sciences said in a statement issued Tuesday.
The signal spike at 11 GHz was detected by the RATAN-600 radio telescope in the southern Russian republic of Karachay-Cherkessia in May 2015, during a campaign that’s part of the worldwide search for extraterrestrial intelligence (a.k.a. SETI).
The detection didn’t come to light until last weekend, but once news started circulating, it touched off parallel observations by the SETI Institute and the Breakthrough Listen Initiative. Those groups focused on the same area of the sky that was the target of the Russian observation: a sunlike star known as HD 164595 in the constellation Hercules.
Nothing noteworthy was detected.
In their statement, the Russian astronomers said last year’s signal initially piqued their interest, but “subsequent processing and analysis of the signal revealed its most probable terrestrial origin.”
The statement provided no further details about the source. However, Russia’s TASS news service quoted astronomer Alexander Ipatov as saying that he and his colleagues at the Special Astrophysical Observatory had detected a similarly “unusual signal” during the Soviet era.
“An additional check showed that it was emanating from a Soviet military satellite, which had not been entered into any of the catalogs of celestial bodies,” TASS quoted Ipatov as saying.
Satellite interference is a prime suspect for SETI false alarms, as the SETI Institute found out in 1997 when a research satellite called the Solar and Heliospheric Observatory set off an alert.
Today the SETI Institute’s senior astronomer, Seth Shostak, said the failure to find a follow-up signal of interest would be consistent with terrestrial interference, including transmissions from a military satellite.
“Look, you can’t always be cynical,” Shostak said in a video report. “If a signal is looking promising, we are going to check it out.”
The Russian astronomers said HD 164595 was just one of many objects targeted during their SETI campaign. “As for the other objects of the RATAN-600 survey, it is too early to claim about any reliable scientific results,” they said. “Using the obtained measurements, we are only able to estimate the upper limit of the detection of the studied areas.”
An earlier version of this report misstated the timing of the Russian statement. Thanks to Daniel Fischer for setting me straight.