According to Paul Gilster, author of the Centauri Dreams website, the Italian astronomer Claudio Maccone and other astronomers affiliated with the search for extraterrestrial intelligence have detected “a strong signal in the direction of HD164595.” HD 164595 is a star of 0.99 solar masses about 95 light years from Earth, with an estimated age of 6.3 billion years. The system is known to have at least one planet, HD 164595 b, which is similar in size to Neptune and orbits its star in 40 days. Other planets may exist in the system as well.
No one is claiming that this is the work of an extraterrestrial civilization, but it is certainly worth further study. Working out the strength of the signal, the researchers say that if it came from an isotropic beacon, it would be of a power possible only for a Kardashev Type II civilization. If it were a narrow beam signal focused on our Solar System, it would be of a power available to a Kardashev Type I civilization. The possibility of noise of one form or another cannot be ruled out, and researchers in Paris led by Jean Schneider are considering the possible microlensing of a background source by HD164595. But the signal is provocative enough that the RATAN-600 researchers are calling for permanent monitoring of this target.
More information may be forthcoming soon. According to Gilster, the discovery and work to understand its origin will be discussed at a SETI committee meeting during the 67th International Astronautical Congress in Guadalajara, Mexico, on Tuesday, September 27.
Ars contacted Nick Suntzeff, a Texas A&M University astronomer, for insight into what this signal at 11Ghz might be if it were not of alien origin. “If this were a real astronomical source, it would be rather strange,” 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.
Suntzeff added that he would not be surprised if the signal was due to a terrestrial origin, because it was observed in part of the radio spectrum used by the military. “God knows who or what broadcasts at 11Ghz, and it would not be out of the question that some sort of bursting communication is done between ground stations and satellites,” he said. “I would follow it if I were the astronomers, but I would also not hype the fact that it may be at SETI signal given the significant chance it could be something military.”