Yeah, it sounds like the first act of a 90s film about aliens, but an international team of scientists from the Search for Extraterrestrial Intelligence (SETI) are looking into a strange signal spike emanating from a 6.3 billion-year-old star located in the constellation Hercules. First detected on May 15, 2015, it wasn't publicly disclosed until Paul Gilster of Centauri Dreams wrote about it over the weekend, saying that researchers were circulating a paper that claimed to have detected "a strong signal in the direction of [the star] HD164595."
The star is 95 light years from here, but that doesn't diminish the significance of what it could mean, however unlikely it may be that it does mean that. The signal was detected via the RATAN-600 radio telescope in Zelenchukskaya, Russia, operated by the Russian Academy of Science. Now, SETI scientists are calling for "permanent monitoring" of the "target" in hopes of better understanding what the signal may have been.
While many hope that it's some kind of civilization living its own life out there in the cosmos, it's entirely possible that it's something like a stellar flare, gravitational microlensing, or even interference from a satellite passing through the telescope's field of vision.
One thing encouraging to those hoping it turns out to be people with heads shaped like an upside down teardrop is the composition of HD164595. It's believed to be remarkably similar to the Earth's Sun and scientists have detected at least one Neptune-like planet in a circular orbit around the star.
"The signal conceivably fits the profile for an intentional transmission from an extraterrestrial source," wrote Alan Boyle, author of The Case for Pluto, "but it could also be a case of earthly radio interference or a microlensing event in which the star's gravitational field focused stray signals coming from much farther away into a singular beam picked up by the telescope. In any case, the blip is interesting enough to merit discussion by those who specialize in the search for extraterrestrial intelligence."
While they're not saying it's aliens, if they were saying it's aliens, the signal's strength would mean that it originated from a fairly advanced society. The commonly used scale for that discussion is the Kardashev scale, which categorizes civilizations based on technological advancement, measured by the amount of the local star's power they're able to harness. If this signal was beamed directly at Earth, it would qualify as a Kardashev Type I civilization, which isn't all that different than our own society.
If the signal was cast in all directions — an isotropic beacon — it would classify as a Kardashev Type II civilization, which would be capable of harnessing the entire power of their sun.
For now, no one is saying it's aliens. The scientists involved have found the signal noteworthy and are beginning to put telescopes in a position where more signals, if they are intentional, would be found. The SETI institute has diverted the Allen Telescope Array in northern California for continuous monitoring.
However, there are plenty of dissenters who think there's nothing to see here. Daren Lynch from SETI@home says, after looking over the raw information, "I was unimpressed. In one out of 39 scans that passed over star showed a signal at about 4.5 times the mean noise power with a profile somewhat like the beam profile... it takes more than that to make a good candidate. Multiple detections are a minimum criterion."
Lynch found it "relatively uninteresting," but others are intrigued. The signal will be discussed further at the IAA SETI Permanent Committee during the 67th International Astronautical Congress in Guadalajara, Mexico on Sept. 27. That's the same day and location that Elon Musk plans on unveiling his plans for colonizing Mars. If you have the week off, it's a great place to try out that new Fox Mulder cosplay suit.