Remain calm: No alien ships are hovering over our cities and no countdown embedded in our comsats has been found! But the Search for Extra-Terrestrial Intelligence has had the astronomy community buzzing all week long over an interesting signal they are looking into, coming from the vicinity of a star almost 100 light-years away. It was actually first noticed more than a year ago, and SETI researchers are now diverting resources to learn more. But no one is saying at this point that it’s LGM:
An international team of researchers has announced the detection of “a strong signal in the direction of HD164595” in a document now being circulated through contact person Alexander Panov. The detection was made with the RATAN-600 radio telescope in Zelenchukskaya, in the Karachay–Cherkess Republic of Russia, not far from the border with Georgia in the Caucasus. The signal was received on May 15, 2015, 18:01:15.65 (sidereal time), at a wavelength of 2.7 cm. The estimated amplitude of the signal is 750 mJy.
David Grinspoon, astrobiologist/author and member of of the Planetary Science Institute, explained to me that “It is legitimately intriguing, and we need to follow up with studies from other observatories (for starters) and try to rule out other natural phenomena.” He added, “There’s no reason to get carried away, but no reason to dismiss it either. I find it tremendously exciting as a reminder that we could find a signal any day!”
The signal was powerful enough that if it came from so far away, and was produced by ET’s, the civilization would be at least Type 1 and probably more like Type 2 on a scale where either rating makes it more advanced than us—the latter significantly so. The star in question is almost identical to the sun in gross physical characteristics right down to the metal content, and it’s estimated to be more than six billion years old. Our solar system is just under five billion years of age, so one thing we can say for sure is HD164595 has been around more than long enough for complex life to develop on one of its planets.
But not everything fits so neatly. Stars like our sun slowly increase their output over billions of years, meaning any planets that were at the right distance for a good long time in this alien system 94.4 light-years away, might now be over heated and more resemble Venus. It also has a planet about the mass of Neptune orbiting closer than Mercury does in our solar system, with a period of about 40 days. If that planet is an ice giant similar to Neptune, it could not have formed so close to HD164595, which means it would have migrated in from much farther away. That process is thought to take millions of years. It’s debatable if a large planet could slowly move in like that without fatally disturbing or completely destroying other, smaller planets in the system’s “Goldilocks zone” as it crossed their respective orbits.
As far as the signal itself, it’s hard to understand what all the ruckus is about. The event lasted only two seconds and has not been observed since. At least one person I talked to speculated credibly that the frequency and duration are consistent with everything from an encrypted military signal to interference arising out of routine terrestrial radio traffic. That means odds are this short outburst has a far more mundane explanation (and indeed, it seems to be of terrestrial origin), and there’s always a good chance that we’ll never know one way or the other. It wouldn’t be the first time that happened. Another brief but intriguing signal was picked up way back in 1977 in a different direction. But that blip never repeated.
Why this signal has received such intense media interest is unclear, similar bursts are picked up from time to time, or every day depending on how one classifies what is a SETI candidate and what is not. But just to be thorough, SETI is reportedly diverting resources to see if they can bag a repeat, or confirm that less exciting explanation:
“The signal is provocative enough that the RATAN-600 researchers are calling for permanent monitoring of this target,” said Gilster. And that’s exactly what is transpiring. As of last night, the SETI institute is diverting its Allen Telescope Array in northern California to investigate while their counterparts at METI International (Messaging Extraterrestrial Intelligence) will use Panama’s Boquete Optical Observatory.