Practitioners of the emerging social science of headline writing has been getting plenty of work this week, as site after site slowly falls to the social media-driven temptation to cash in on the “possibility” of alien life. SETI, it turns out, is looking at a star, which has of course never happened before, and so it’s time to dust off the sort of verbiage that can cut through cynicism and energize a reading population that has heard a whole lot of scientists cry wolf over the years. “Not a Drill: SETI Is Investigating a Possible Extraterrestrial Signal From Deep Space,” said the Observer, while New Scientist thrilled that a “Mysterious SETI signal sends alien-hunting telescopes scrambling.”
There’s just one problem: even SETI doesn’t actually think this is anything, saying that it isn’t “terribly promising” from their perspective.
The background: a team of astronomers working at the RATAN-600 telescope in Russia are circulating a paper showing an anomalous strong RF signal in the direction of HD164595. This star is roughly Sun-sized and it’s known to have at least one orbiting planet, though not much is known about them. At 11 Ghz, the signal is in an odd part of the spectrum, but at present there’s no information about power of the signal as a function of frequency. This signal lasted much longer than the “fast radio bursts” that have long confused astronomers; with such odd attributes, could this really be a signal from alien life?
Well, answering that question is SETI’s whole reason for existing, and that’s exactly what it’s doing here. When there’s a candidate for a life-proving signal, SETI’s mission statement demands that they look at the same source with a separate instrument (their instruments) and see if they can corroborate the observation. If not, and the observation is generally discarded, at least in the short term. There have already been attempts to replicate the result; as the researchers say, absence of evidence is not evidence of absence of extraterrestrial life, but as the researchers imply, it sure doesn’t help.
This team presents their RATAN-600 reading with evidence that their signal is unlikely to be an equipment malfunction — but they also only report one iteration of this signal, out of many readings taken. If the signal is real, it doesn’t seem to repeat on any reasonably quick timeline, which we would sort of expect of a signal created by extraterrestrial intelligence. Perhaps this was some signature of a distant galactic cataclysm, an intelligent race violently destroying itself in a great explosion — but probably not.
One thing that’s often forgotten about this observation is that it is more than a year old and only came to light when reported this month. Texas A&M University astronomer Nick Suntzeff told Ars that it’s possible the signal was military in origin, and very likely originated on Earth itself. SETI astronomer Seth Shostak also claimed that “the known planet around the star is in an awfully tight orbit, which means it’s probably a place that’s hotter than Seattle’s best restaurant.” I may not get that joke, but it still clear that he’s saying it’s not reasonable to get too excited just yet. If any of the planets on HD164595 really could be host to aliens, SETI’s readings should make that clear.
Additionally, the RATAN-600 reading is itself a bit of a problem. As SETI notes, the receiver has a bandwidth of 1 GHz, or a billion times wider than those SETI normally uses. “The strength of the signal was 0.75 Janskys,” they said, “or in common parlance, ‘weak.’” What’s unclear is whether it was weak because the signal is insignificant, or because the origin is so far away, or because of the wide-open nature of the receiver, which can dilute the power of narrow band signals? Or, in the most unlikely case, was it weak because it’s coming through some sort of Dyson Sphere-like alien megastructure?
If this is a signature of intelligent life, however, it’s almost certainly meant to be picked up; there aren’t very many actions astronomers can think of that would create such a signal for any reason other than to intentionally create such a signal. They say that if it is a beacon it could be of two general types: isotropic, or blaring loudly in all directions, or narrow beam, or focused very specifically on Earth.
If it’s an isotropic beacon creating a signal of this intensity in all directions, the civilization behind it would need to be extremely advanced — advanced enough to harness all the power of a star, since the power draw would be something like a hundred billion gigawatts, or millions of times more than humanity currently generates across the globe.
If it’s a focused beam beacon shouting only to us, it could plausibly come from being only slightly more advanced than ourselves — put all of mankind’s current generation capacity to work, and you might be able to power such a device it. However, there’s another problem with that idea: the host star is so far away that no human transmissions will have reached it yet (we’re too young as a technological species) and so these aliens would have no reason to point their big beacon at our system. Unless they’ve already come here with their warp drives and checked us out, then gone back home and for some reason set up a big, ambiguous-looking space beacon. Which, you know, maybe.
Surely, just a few years away.
In general, this is what SETI does: it looks into anomalous readings produced by the rest of the world and sees whether it’s likely to be aliens. It’s not news when something gets passed to SETI, only when something comes out the other side and it still looks like ET. Barring some absurdly clear signal like the one from Contact, that is when the hyperbole will become warranted.
In that spirit, don’t forget that KIC 8462852 (AKA the “alien megastructure star”) is getting another look by SETI in October of this year, so if you want to get excited about unlikely sources of the greatest discovery in human history, that’s probably where you want to focus your attention.