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posted by janrinok on Tuesday October 25 2016, @02:43AM   Printer-friendly
from the take-me-to-your-leader dept.

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.


Original Submission

 
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  • (Score: 2) by NotSanguine on Tuesday October 25 2016, @03:51AM

    by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday October 25 2016, @03:51AM (#418391) Homepage Journal

    An oversight on my part. I've added a link to the 2012 paper in TFS.
    Thanks for the catch!

    --
    No, no, you're not thinking; you're just being logical. --Niels Bohr
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  • (Score: 2, Informative) by tftp on Tuesday October 25 2016, @04:36AM

    by tftp (806) on Tuesday October 25 2016, @04:36AM (#418400) Homepage

    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. The paper seems to be very naive and talks about pretty obvious things. A modern RF engineer deals with far more complex DSP on a daily basis. 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.

    I will wait for the reviews to come in. But if I were to review the article, I would question the proposed scenario that an advanced alien civilization will be sending us essentially an uncoded, unmodulated carrier. Also,

    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.

    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.

    • (Score: 2) by FatPhil on Tuesday October 25 2016, @05:11AM

      by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Tuesday October 25 2016, @05:11AM (#418404) Homepage
      The 2016 paper came over as being just as naive, it's painful to read.

      The 2012 paper also has the great line "Consequently, a good way to let others know of their existence is to generate a signal that is so unusual that it can only be artificial (Tarter 2001)." Which basically disproves the 2016 paper, as apparently this signal's pretty common. (It contains only a dozen of so bits of entropy.)

      What did you make of the "10^4" bit uder figure 5 in 2016? Sounds like "what we claim isn't visible in the data, so we added 10000 lots of what we want to see in the data in order to make it visible" to me.

      My conclusion: Loon. Or at least someone so entrenched in milking his own confirmation bias that he can be safely ignored.
      --
      Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
      • (Score: 2) by FatPhil on Tuesday October 25 2016, @05:21AM

        by FatPhil (863) <pc-soylentNO@SPAMasdf.fi> on Tuesday October 25 2016, @05:21AM (#418406) Homepage
        I also love his inability to simplify sin (2 pi nu tau / 2)
        --
        Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
    • (Score: 2) by jimshatt on Tuesday October 25 2016, @07:26AM

      by jimshatt (978) on Tuesday October 25 2016, @07:26AM (#418430) Journal
      Disclosure: I haven't read TFA.
      Could it be that the signals, while artificial, were not meant as a beacon. Sure, there are better ways to transmit a beacon or a SETI message, but maybe the signals weren't meant for us to receive. To prove alien intelligence we don't need to prove an intent to contact us.
      • (Score: 2) by HiThere on Tuesday October 25 2016, @07:04PM

        by HiThere (866) Subscriber Badge on Tuesday October 25 2016, @07:04PM (#418678) Journal

        Also haven't read the article.

        What are the energy requirement for this kind of transmission? This is what causes me to be immediately skeptical. If the signals were produced by modulating their star, this would seem to do strange things to their weather. So I also guess that there are natural causes.

        --
        Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
    • (Score: 4, Interesting) by NotSanguine on Tuesday October 25 2016, @08:44AM

      by NotSanguine (285) <NotSanguineNO@SPAMSoylentNews.Org> on Tuesday October 25 2016, @08:44AM (#418440) Homepage Journal

      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.

      I had a similar thought (hence the question at the end of TFS) and agree that this is more likely from some natural process.

      However, I think the implication that the paper's authors are going for is that since these are "sun-like" stars, they could have a similar propensity for life/intelligent life and, assuming Kardashev [wikipedia.org] Type I (or even Type II) or lower level civilizations, it seems unlikely that such a civilization would have the capability to set up shop around a variety of stars just to show others they can communicate.

      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.

      This is a much more convincing argument, assuming that such signals from another civilization are intended to be received and understood by other civilizations. Which could be a pretty big assumption.

      Given the type of signals, it seems unlikely that these are artificial. But even if they are, they likely weren't meant to be an advertisement for such a civilization.

      --
      No, no, you're not thinking; you're just being logical. --Niels Bohr
      • (Score: 2) by JoeMerchant on Tuesday October 25 2016, @12:37PM

        by JoeMerchant (3937) on Tuesday October 25 2016, @12:37PM (#418501)

        Look at our "intentional contact" signals vs our random emissions, we've got more "I Love Lucy" going out than SETI, by orders of magnitude. Some of the SETI signals were intentionally strong, but mostly, they're just buried in a background of internal chatter that leaked out.

        --
        🌻🌻 [google.com]
      • (Score: 2) by bradley13 on Tuesday October 25 2016, @03:32PM

        by bradley13 (3053) on Tuesday October 25 2016, @03:32PM (#418581) Homepage Journal

        There's really no way around it: we make a lot of assumptions. We assume that any civilization will send using the electromagnetic spectrum. We assume that they will send us something intelligible, like prime numbers. We assume that they will format this information in a way that we can decode.

        We cannot even manage to understand animal speech, on a planet where we are closely related to the animals involved. What is it that the chimpanzees are communicating to each other? Whales? Dolphins? We have only the vaguest of ideas, even though their communication ought to be very simple and limited.

        Or consider dogs: we're not only both mammalian, we've lived with them for thousands of years. Yet the communication that they have with each other through scent is, literally, beyond our comprehension.

        And we think we'll be able to communicate with aliens?

        --
        Everyone is somebody else's weirdo.
        • (Score: 0) by Anonymous Coward on Tuesday October 25 2016, @04:21PM

          by Anonymous Coward on Tuesday October 25 2016, @04:21PM (#418598)

          We assume that any civilization will send using the electromagnetic spectrum.

          No. But if they are not sending in the electromagnetic spectrum, we won't currently be able to receive their signals. So we look at the electromagnetic spectrum because that's the only place where we can at least hope to find something.

          Imagine you are in a desert, and in one direction there might be an oasis within your reach, and in another direction it is far more likely that there is an oasis, but any oasis there may be is definitely out of reach. Which direction will you go to?

          We assume that they will send us something intelligible, like prime numbers. We assume that they will format this information in a way that we can decode.

          If there are actually any aliens actively trying to contact us, it is very likely that they will use something they can hope us to understand. Which almost certainly means using something involving the fundamental properties of natural numbers, as those are independent of any culture. Of course we cannot know for sure, but then, if we can't understand it, it might as well not be there, so again the original point applies: We look for what we can recognize, because that's the only thing we can hope to find.

          We cannot even manage to understand animal speech, on a planet where we are closely related to the animals involved.

          Well, in those cases where the animals try to tell us something, they usually succeed quite well. Maybe you've never had a pet, or else you'd know.

    • (Score: 0) by Anonymous Coward on Tuesday October 25 2016, @04:48PM

      by Anonymous Coward on Tuesday October 25 2016, @04:48PM (#418614)

      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.