SoylentNews is people
SoylentNews
Phys.org is reporting on a paper which details some interesting phenomena which could be evidence of advanced civilizations.
From the Phys.org article:
We all want there to be aliens. Green ones, pink ones, brown ones, Greys. Or maybe Vulcans, Klingons, even a being of pure energy. Any type will do.
That's why whenever a mysterious signal or energetic fluctuation arrives from somewhere in the cosmos and hits one of our many telescopes, headlines erupt across the media: "Have We Finally Detected An Alien Signal?" or "Have Astronomers Discovered An Alien Megastructure?" But science-minded people know that we're probably getting ahead of ourselves.
[...] What we're talking about here is a new study from E.F. Borra and E. Trottier, two astronomers at Laval University in Canada. Their study, titled "Discovery of peculiar periodic spectral modulations in a small fraction of solar type stars" was just published at arXiv.org. ArXiv.org is a pre-print website, so the paper itself hasn't been peer reviewed yet. But it is generating interest.
The two astronomers used data from the Sloan Digital Sky Survey, and analyzed the spectra of 2.5 million stars. Of all those stars, they found 234 stars that are producing a puzzling signal. That's only a tiny percentage. And, they say, these signals "have exactly the shape of an ETI signal" that was predicted in a previous study by Borra.
Prediction is a key part of the scientific method. If you develop a theory, your theory looks better and better the more you can use it to correctly predict some future events based on it. Look how many times Einstein's predictions based on Relativity have been proven correct.
The 234 stars in Borra and Trottier's study aren't random. They're "overwhelmingly in the F2 to K1 spectral range" according to the abstract. That's significant because this is a small range centred around the spectrum of our own Sun. And our own Sun is the only one we know of that has an intelligent species living near it. If ours does, maybe others do too?
The authors acknowledge five potential causes of their findings: instrumental and data reduction effects, rotational transitions in molecules, the Fourier transform of spectral lines, rapid pulsations, and finally the ETI signal predicted by Borra (2012). They dismiss molecules or pulsations as causes, and they deem it highly unlikely that the signals are caused by the Fourier analysis itself. This leaves two possible sources for the detected signals. Either they're a result of the Sloan instrument itself and the data reduction, or they are in fact a signal from extra-terrestrial intelligences.
Are these signals just evidence of some, as yet undiscovered, property of stars, or are these "transmissions" the alien equivalent of an episode of "The Bachelor"?
2012 paper predicting the signals reported on by Borra, et. al.
(Score: 0) by Anonymous Coward on Tuesday October 25 2016, @04:48PM
I have read the 2012 paper a moment ago, and it looks like the author learned about the wonders of Fourier transforms only a week ago and is in a hurry to share their discovery with the world.
I've only glanced at the 2012 paper, and not looked at the 2016 one at all -- I got the same sort of vibe.
An on-off keying will provide the spectrum in question, but it would be far more interesting to see more complex signals, that are far more noise-resistant and offer higher bandwidth that can be used for forward error correction, for example.
Yeah, but there's actually some basis for that, for a given set of suppositions. If the aliens want to signal their existence, and want this signal to be received by other cultures as early as possible, then this could make sense. It's a strategy to make sure the signal shows up on routine astronomical observations. Other types of signals, while better for communication, may require more effort on the receiver's end to be aware the signal exists. Presumably, a culture sending such a signal would send one or more coded signals in parallel -- the unmodulated carrier gets your attention during spectrographic surveys, then you start paying close attention and spot the coded signal on whatever frequency.
they are present in only a very small fraction of stars within a narrow spectral range
As the aliens have no obvious reason to choose exactly this spectral range for a beacon, it is equally - if not more - likely that the observed frequencies are produced by a natural process that is typical to stars in exactly this spectral range. If I were an alien in charge of that transmission, I'd use all kinds of stars to make it obvious to the observer that a natural process is not likely to span so many different star configurations, periods of life and other unique physics.
Does "the evolution of intelligent life with an interest in SETI" qualify as a "natural process that is typical to stars in exactly this spectral range"?
Others have pointed this out, but the authors' idea seems to be that this indicates something closer to 234 cultures each with a beacon at their home star rather than 1 culture with beacons at 234 stars. The underlying assumption is that (at the time these signals originate) they had little interstellar travel capability, and if they did have it, only used it to travel to very similar systems (presumably because those were the ones with "interesting" planets in their equivalent of the habitable zone). Whereas you're assuming one culture with interstellar travel cheap enough to go to inhospitable stars to set up SETI beacons (and scientific observations, but still).
I don't think we know enough to determine which set of assumptions is more likely.
Of course, anytime someone starts talking about stars like Sol being uniquely suited to life, one must be wary -- remember all the assumptions of our solar system being typical that got thrown out when we started uambiguously detecting exoplanets. But then again, if life does exist around all types of stars, it may be true that life originating at stars similar to ours are more likely to be similar to us, and thus to have a better chance at effective communication.
In the end, we will be sure that we see a SETI message only when it is undeniably artificial. Say, a sequence of prime numbers followed by a checksum of the last 1024 entries; or a grid of X and Y (and maybe Z) that are primes, and the content of the array makes sense. That was the format of some SETI messages that were sent from this planet.
Agreed, although more the former than the latter, as I question the idea of an array that "makes sense" between alien cultures. (Both in the context of us recognizing such a thing when we receive it, and of it being a useful format for us to transmit.)
But yeah, if this "discovery" checks out, the next step is to pay some serious attention to these systems, looking for such coded signals.