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KIC 8462852: The SETI Factor

I had no idea when the week began that I would be ending it with a third consecutive post on Dysonian SETI, but the recent paper on KIC 8462852 by Tabetha Boyajian and colleagues has forced the issue. My original plan for today was to focus in on Cassini’s work at Enceladus, not only because of the high quality of the imagery but the fact that we’re nearing the end of Cassini’s great run investigating Saturn’s icy moons. Then last night I received Jason Wright’s new paper (thanks Brian McConnell!) and there was more to say about KIC 8462852.

Actually, I’m going to look at Wright’s paper in stages. It was late enough last night that I began reading it that I don’t want to rush a paper that covers a broad discussion of megastructures around other stars and how their particular orbits and properties would make them stand out from exoplanets. But the material in the paper on KIC 8462852 certainly follows up our discussion of the last two days, so I’ll focus on that alone this morning. Next week there will be no Centauri Dreams posts as I take a much needed vacation, but when I return (on October 26), I plan to go through the rest of the Wright paper in closer detail.

A professor of astronomy and astrophysics at Penn State, Wright heads up the Glimpsing Heat from Alien Technologies project that looks for the passive signs of an extraterrestrial civilization rather than direct communications, so the study of large objects around other stars is a natural fit (see Glimpsing Heat from Alien Technologies for background). Luc Arnold suggested in 2005 that large objects could be used as a kind of beacon, announcing a civilization’s presence, but it seems more likely that large collectors of light would be deployed first and foremost as energy collectors. We’ve also seen in these pages that a number of searches have been mounted for the infrared signatures of Dyson spheres and other anomalous objects (see, for example, An Archaeological Approach to SETI).

In the last two days we’ve seen why KIC 8462852 is causing so much interest among the SETI community. The possibility that we are looking at the breakup of a large comet or, indeed, an influx of comets caused by a nearby M-dwarf, is thoroughly discussed in the Boyajian paper. This would be a fascinating find in itself, for we’ve never seen anything quite like it. Indeed, among Kepler’s 156,000 stars, there are no other transiting events that mimic the changes in flux we see around this star. Boyajian and team were also able to confirm that the striking dips in the KIC 8462852 light curve were not the result of instrument-related flaws in the data.

So with an astrophysical origin established, it’s interesting to note that Boyajian’s search of the Kepler dataset produced over 1000 objects with a drop in flux of more than ten percent lasting 1.5 hours or more, with no requirement of periodicity. When the researchers studied them in depth, they found that in every case but one — KIC 8462852 — they were dealing with eclipsing binaries as well as stars with numerous starspots. The object remains unique.

Wright provides an excellent summary of the Boyajian et al. investigations. The Kepler instrument is designed to look for dips in the light curve of a star as it searches for planets. If the frequent dips we see at KIC 8462852 are indeed transits, then we must be looking at quite a few objects. Moreover, the very lack of repetition of the events indicates that we are dealing with objects on long-period orbits. One of the events shows a 22 percent reduction in flux, which Wright points out implies a size around half of the stellar radius (larger if the occulter is not completely opaque). The objects are, as far as we can tell, not spherically symmetric.

Let me quote Wright directly as we proceed:

The complexity of the light curves provide additional constraints: for a star with a uniformly illuminated disk and an occulter with constant shape, the shape of the occulter determines the magnitude of the slope during ingress or egress, but not its sign: a positive slope can only be accomplished by material during third and fourth contact, or by material changing direction multiple times mid-transit (as, for instance, a moon might). The light curves of KIC 8462 clearly show multiple reversals… indicating some material is undergoing egress prior to other material experiencing ingress during a single“event”. This implies either occulters with star-sized gaps, multiple, overlapping transit events, or complex non-Keplerian motion.

Screenshot from 2015-10-16 09:18:25

Image: Left: a deep, isolated, asymmetric event in the Kepler data for KIC 8462. The deepest portion of the event is a couple of days long, but the long “tails” extend for over 10 days. Right: a complex series of events. The deepest event extends below 0.8, off the bottom of the figure. After Figure 1 of Boyajian et al. (2015). Credit: Wright et al.

A giant ring system? It’s a tempting thought, but the dips in light do not occur symmetrically in time, and as Wright points out, we don’t have an excess at infrared wavelengths that would be consistent with rings or debris disks. Comet fragments remain the most viable explanation, and that nearby M-dwarf (about 885 AU away from KIC 8462852) is certainly a candidate for the kind of system disrupter we are looking for. That leaves the comet explanation as the leading natural solution. A non-natural explanation may raise eyebrows, but as I said yesterday, there is nothing in physics that precludes the existence of other civilizations or of engineering on scales well beyond our own. No one is arguing for anything other than full and impartial analysis that incorporates SETI possibilities.

Jason Wright puts the case this way:

We have in KIC 8462 a system with all of the hallmarks of a Dyson swarm… : aperiodic events of almost arbitrary depth, duration, and complexity. Historically, targeted SETI has followed a reasonable strategy of spending its most intense efforts on the most promising targets. Given this object’s qualitative uniqueness, given that even contrived natural explanations appear inadequate, and given predictions that Kepler would be able to detect large alien megastructures via anomalies like these, we feel [it] is the most promising stellar SETI target discovered to date. We suggest that KIC 8462 warrants significant interest from SETI in addition to traditional astrophysical study, and that searches for similar, less obvious objects in the Kepler data set are a compelling exercise.

As I mentioned, the Wright paper discusses the broader question of how we can distinguish potential artificial megastructures from exoplanet signatures, and also looks at other anomalous objects, like KIC 12557548 and CoRoT-29, whose quirks have been well explained by natural models. I want to go through the rest of this paper when we return to it in about ten days.

The paper is Wright et al., “The Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies. IV. The Signatures and Information Content of Transiting Megastructures,” submitted to The Astrophysical Journal (preprint).

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Comments on this entry are closed.

  • Triffin October 19, 2015, 10:43

    Long time reader
    First time poster

    Could an Oort cloud, either natural or artificial ( ie our
    ‘aliens’ may have moved local objects to create the ‘cloud’ )
    create the light signature(s) observed ??

    Triff ..

  • Steve White October 19, 2015, 11:47

    ALEX TOLLEY: I agree with you! I’m certainly not saying every strange signal or circumstance detected in the universe should be declared “Aliens”. I AM saying “Skeptical” can be pushed to an extreem and actually stand in the way of discovery.

    And here I go with cracker barrel psychology, but I seem to detect -not just healthy skepticism-but an absolute *reluctance*, even deep seated dread of finding actual extra-terrestrial life, let alone INTELLIGENCE. I think this is rooted in the old “Earth is the center of the universe” concept. We lost that special position. I remember all the old astronomy books and their discussion of how rare planets probably were, you know, by being created a stars approaching each other closely. Now we know or suspect thousands of them and millions or billions not yet discovered. So we’ve lost THAT special distinction, too. And Darwin took away our “Special Creation”, of course.

    Now it’s LIFE, especially intelligent life, that remains the last bastion of human uniqueness. Deep down even scientist don’t REALLY want to give that up. So, yes, they will bend, distort and torture a “natural” explanation to the point of absurdity…perhaps not even consciously, rather than surrender that last little bit of “WE are the reason for existence.” We are the center of the universe.

    And if that seems unnecessarily harsh towards scientists?- well, they are, after all HUMAN.

  • Steve White October 19, 2015, 11:56

    ALEX TOLLEY: Man, did I screw this sentence up. ” I remember all the old astronomy books and their discussion of how rare planets probably were, you know, by being created a stars approaching each other closely.”

    Should say”By being created by the close approach of two stars.”

    Sorry.

  • allison October 19, 2015, 12:47

    By how much is KIC 8462852 varying in apparent magnitude? I was thinking about attempting some visual observations (just for fun, really) provided that the fadings were sufficiently great to be noticeable (say, a half-magnitude or so).

  • TLDR October 19, 2015, 12:58

    Coupla engineering type questions.
    Of course, I’ve never built me a Dyson sphere, so what do I know; I am just speculating.

    Wouldn’t it take an ungodly amount of energy to build a Dyson sphere, possibly even more than you could harvest? Or more sanely, if you have enough energy to build a Dyson sphere, why are you bothering with it?

    It’s been suggested that one of the structures might be a mirror built for reflecting energy back into the star, thus causing the star to move across space. Now I flunked physics, but wouldn’t the light from the star tend to push a reflector away from the star, as we have seen with recent solar sail experiments?

    But what do I know, I am just an ignorant Earthling.

  • Harry R Ray October 19, 2015, 14:03

    It just gets wierder and wierder! The ROTATION RATE FOR THIS STAR is ONLY 0.88 days! That’s WAY TOO FAST for a middle-aged to old star! Stars like this do NOT ratate this fast without some outside impetus: Case in point; Tau Bootis. BUT: that would mean, that; if, the star is co-rotating with a hot jupiter or brown dwarf, that object would have an orbital period of less than one day! Even though the star is 1600+ light years away, the planet or brown dwarf should be detectible via the radial velocity method. Since the star is tipped 68 degrees, even grazing transits would not happen. This would also mean that the star is somewhat oblate, although NOTHING like Altair or Aschernar. Other methods to speed up the star’s rotation(or KEEP it fast) seem even less likely, though minutely possible. The “last resort ” explanation would be that ET”s at the K2 level have either increased the star’s rotation, or, have kept it fast for over a billion years. A sobering thought indeed. If so WHY would they do it? Any ideas? LJK: WTF-001 may not be a strong enough “statement” nomenclature. More like WTFF-001!

  • Jim Strom October 19, 2015, 14:48

    @TLDR:

    The energy would be self-providing. Just like with a human solar panel, eventually, a solar panel will reach the energy break-even point, where it has produced energy equal to the energy needed to bring it online, and then it is producing “free energy”. A Dyson sphere could be built incrementally this way, over thousands or millions of years. The math has been done elsewhere (and the time required drops if you assume that the civilization’s technology/efficiency continues to improve).

    To me, the important part of understanding why megastructures are not unrealistic is to consider the timescales we could be talking about. There is the notion that for most planets with intelligent life, at any time, the intelligent life on any planet will be either “apes” or “gods”. In other words, the transition from technologically primitive to technologically advanced is cosmologically fast. Suppose half of all intelligent planets are in the advanced category. On average, they will have been “advanced” for millions or billions of years. Given such time, a civilization could easily build structures paving a transit profile of planet or star scale. Such hypothetical structures can essentially be two-dimensional, so they can have a big “transit” signature without necessarily involving star or planet scale _mass_.

  • Rob October 19, 2015, 15:22

    I am having trouble wrapping my head around the possible natural explanations. For instance if it was a large comet that was broken up, there was no infrared radiation that was observed, which should be the case if there was a great deal of cometary dust, which should be a massive amount to cause the dips they’re talking about. And the orbit of the objects seems to be irregular, which wouldn’t be consistent with a planet, would it? And as far as a star, the objects do not emit any light so that’s impossible, right? So what is it? I am left to consider that however outrageous, and until concrete proof is given, that it could be some partial Dyson structure or perhaps even some type of massive alien ship. Who knows. I’m very intrigued.

  • Alex Tolley October 19, 2015, 15:25

    @Steve White

    Now it’s LIFE, especially intelligent life, that remains the last bastion of human uniqueness. Deep down even scientist don’t REALLY want to give that up. So, yes, they will bend, distort and torture a “natural” explanation to the point of absurdity…perhaps not even consciously, rather than surrender that last little bit of “WE are the reason for existence.” We are the center of the universe.

    I have to disagree with you there. I don’t think that is the mindset of the scientists I know. I do think that Feynman’s point :”The first principle is that you must not fool yourself — and you are the easiest person to fool.”, is more relevant, and this will also be associated with being fooled and with it ridiculed.

  • Eric S. October 19, 2015, 15:33

    Re: the comet hypothesis…

    Is it possible we’re looking in the wrong solar system for these comets? I’m thinking a large sun-grazer (in *our* solar system) that broke apart into a stream of objects and (by incredible luck) happens to be transiting this star at some very distant part of its orbit. The asymmetries in the light curves could then be traced to shapes of the individual objects.

    Anyway, just a thought, since we really, REALLY need to exhaust all more mundane explanations before the far more exciting one.

  • Hiro October 19, 2015, 16:20

    I wish we have a big space telescope orbiting around 550 AU from Sol during interesting time like this.

    Well, a big difference between a pro and an ordinary amateur or layman is abnormal patience. We must wait for several more years conducting more rigorous observations in order to find the most reasonable answer to this phenomenon. About 3 years ago, a FTL neutrinos hype in Italy became a bad experimental research. We shouldn’t think basing on our emotions which usually lead us to dead ends.

  • Michael October 19, 2015, 16:23

    @Triffin October 19, 2015 at 10:43

    ‘Long time reader
    First time poster’

    Nice to see you posting.

    Could an Oort cloud, either natural or artificial ( ie our
    ‘aliens’ may have moved local objects to create the ‘cloud’ )
    create the light signature(s) observed ??’

    These objects are BIG but not what I would call artificial. I would expect a more organised engineering project. i.e. start at the equator of the star and move around it in a segmented fashion. As for moving these Oort cloud objects inwards to work on them they are been very messy about it. All that uncontrolled dust/gas could cause a transport problems to fast moving craft. I am afraid it is a ‘Nothing to see please move along’ moment but one we should not ignore as it teaches us a lot about the universe we are in.

  • Michael October 19, 2015, 16:32

    @Harry R Ray October 19, 2015 at 14:03

    ‘It just gets wierder and wierder! The ROTATION RATE FOR THIS STAR is ONLY 0.88 days! That’s WAY TOO FAST for a middle-aged to old star! Stars like this do NOT ratate this fast without some outside impetus:’

    I was taken a back by this as well, it could be a young star as it has quite a noisy light curve or few planets formed around it, if we did not have planets in our system our Sun would rotate even faster than this star! Planets have a lot of orbital momentum.

    ‘If so WHY would they do it? Any ideas? LJK: WTF-001 may not be a strong enough “statement” nomenclature. More like WTFF-001!’

    They could increase the life span of their Star by reducing the pressure on the core through centrifugal action.

  • Jim Galasyn October 19, 2015, 16:53

    Harry R Ray: “The rotation rate for this star is only 0.88 days,” and “the star is tipped 68 degrees”.

    More evidence that this is a gravity darkening effect, as described in the paper posted by Michael, upthread:

    MEASUREMENT OF SPIN-ORBIT MISALIGNMENT AND NODAL PRECESSION FOR THE PLANET AROUND PRE-MAIN-SEQUENCE STAR PTFO 8-8695 FROM GRAVITY DARKENING
    http://arxiv.org/abs/1308.0629

  • david lewis October 19, 2015, 18:34

    Rotation period of 0.88 days?

    Maybe someone/something is trying to speed up the star’s rotation until it tears itself apart so they can harvest the materials. Or maybe not. I wonder just how fast a star would need to rotate before it started tossing material into space. A full star’s worth of mass would make a lot of space colonies.

  • Triffin October 19, 2015, 19:06

    @Jim Strom

    I can’t believe that any advanced ET that had the technology to build a
    mega structure, especially one designed to harvest stellar energy, would
    even bother as they would surly be capable of designing and building fusion
    machines of any size/energy density that they might require ..

    If “they” are millions or billions of years more advanced than we are then
    I’m not sure there would be a need for any “structure” that we would recognize .. With regards to Fermi’s Paradox ..
    Perhaps the “great filter” is technology ..
    Not that intelligent species can’t manage their technology,
    but rather that sufficiently advanced biologic life will inevitably
    merge with their technology and become what we have in the past
    and still do call “God” .. beings that have transcended biology ..

    Idle speculation on my part .. I know ..
    But, I’d give anything to fast forward 500 years or so just to
    see how it all turns out

    Triff ..

  • Martin October 19, 2015, 21:23

    Hello from Argentina :)
    Could be the events of same shape but different size due to FRACTAL swarm arrangement or structure?

    http://3.bp.blogspot.com/-6L7Kqy2IZR4/UcVbhqjvA9I/AAAAAAAAl00/rcNdc7q5VnQ/s1600/3dfractalssubmicron.jpg

  • kamal ali October 19, 2015, 23:00

    Harry: pls give citation for the 0.88d period and 68degree inclination.

    elsewhere I saw that the authors believed this NOT to be a young star. *IF* it were young, its more likely to have non-dispersed gas (altho AFAICT not dust because that would radiate in IR).

  • Rafik October 20, 2015, 4:18

    I know it is slightly off topic but the implications could be significant in the search for life on exoplanets. The odds that life is just a natural extension of inorganic chemistry may have just jumped considerably.

    http://www.themarketbusiness.com/2015-10-20-life-on-the-earth-began-millions-of-years-earlier-than-previously-thought

    “Life on Earth may have started almost instantaneously,” said one of the lead researchers, Mark Harrison, a geochemist from the University of California, Los Angeles. “With the right ingredients, life seems to form very quickly.”

    “Researchers have found evidence of ancient micro-organisms that lived in what is now Western Australia at least 4.1 billion years ago. If confirmed, the discovery suggests that life originated on Earth 300 million years earlier than previously thought.”

  • Rafik October 20, 2015, 4:30

    Another report on the “discovery” of 4.1 billion year old life – with some scepticism.

    http://www.abc.net.au/news/2015-10-20/ancient-crystals-reveal-life-could-be-older-than-thought/6870678

    However, critics are open to the possibilities –
    Professor Nemchin said he believes the scientists did the best they could with the current “development of our understanding and analytical methods”.
    “To some extent it confirms the idea that life probably existed very early, almost from the beginning of the planet itself and the solar system itself and probably not really restricted to our planet,” he said.

  • Michael October 20, 2015, 8:26

    @kamal ali

    It is in the paper,

    ‘We determine that
    KIC 8462852 is a main-sequence F3 V/IV star, with a rotation period 0:88 d, that exhibits no significant IR excess.’

    ‘we determine a stellar rotation axis inclination of 68 degrees.’ Page 5

    ‘Overall, the star’s spectrum is unremarkable, as it looks like an ordinary early F-star with no signs of any emission lines or P-Cygni profiles.’

    http://arxiv.org/pdf/1509.03622v1.pdf

  • Harry R Ray October 20, 2015, 9:54

    Michael: ALL INDICATIONS POINT to this NOT being a youbg star! One thing that escaped me prior to now is that it could be an EVOLVED blue straggler that has STILL not had the time to spin down AFTER the merger of the two old stars that formed it. david lewis: MAYBE, but they would have to make it go A LOT FASTER! Case in point, Altair and Aschernar are STILL VERY STABLE!

  • PW October 20, 2015, 11:53

    A couple of questions about this star:

    Is this F3 a stable star, not a variable that has caused Kepler confusion in the past?
    Have any planets been found in it’s habitable zone?

    I am curious because, if this system doesn’t look like it has produced advance life on it’s own, it would mean that “the ETs” had to get to it to utilize it. Which of course implies that they had developed interstellar capabilities far exceeding desperation, one way generation ships. FTL even? If that were the case, we should have been aware of their visits to earth.
    Meanwhile, it is difficult to imagine that an advanced civilization would follow right along with our primitive notions of Dyson Spheres. They would be powering things up with far less difficulty than building something like that.

  • Steve White October 20, 2015, 14:53

    ALEX TOLLEY: “I have to disagree with you there. I don’t think that is the mindset of the scientists I know. I do think that Feynman’s point :”The first principle is that you must not fool yourself — and you are the easiest person to fool.”, is more relevant, and this will also be associated with being fooled and with it ridiculed.”

    Strangely, I think this illustrates the point I’m trying to make. Since the possibility of being in error, (Fooled) is always there, especially dealing with something thousands of light years away, what is the best way to handle that risk? A natural explanation no matter how big a “reach” it might be, OR Dyson Sphere building ETS with lots of time on their …”hands”?

    Obviously, the natural explanation is safest. You know, ANYBODY can be wrong, well gee, at least he didn’t go off the deep in with silly “Alien” stuff. I doubt any scientist in any field would object to THAT error too much. But to risk calling it ET, and being wrong? OH my gosh the laughter.

    So I KNOW the forgone conclusion will be “natural” no matter how unlikey or how stretched. And, yes, I’d make book on it.

  • TLDR October 20, 2015, 17:05

    @Triffin, I agree that we are trying to second-guess civilizations that are millions of years more advanced than ours (or more accurately we are indulging in thought experiments). We are all guilty of imprinting our aliens with anthromorphism, but it’s all we have right now.

    Bottom line is, IF there are ETCs out there, they may reveal their existence in ways that we may be able to detect, even in seemingly natural phenomena. And it’s an open mind that will first discover ET life.

  • Steven Ward October 20, 2015, 17:19

    This is a very fascinating subject. I have been following Centauri Dreams for almost four years now. This KIC 8462852 post, actually posts, three now? has really got me excited, and everyone else apparently. I have been pleasantly surprised how many comments have been posted here. I sure enjoy reading them, it makes my day.

    I have a question, in the past few years, or forever I guess, has there been another instance of a bizarre astronomical discovery that has brought on so much attention and alien speculation? To me, this seems like the big one (not meaning that I expect this to be actual ETI).

  • Daniel Högberg October 20, 2015, 17:27

    I dont believe in Dyson spheres. Why would an advanced civilization build such an enormous structure when they probably have fusion power on a chip already? I believe large dead empty space habitats is something we may find though. Technology will develop so fast that in a timespan of only a few hundred years and up to around a thousand years, all technological civilisations will in the end be uploaded to their own artificial “game-worlds” / and or their version of our internet. Why would you not want live in world where you can do anything, be anything, and create anything. Why would you not want live in a world where only your imagination is the limit to what you can achieve? Thats why the universe is so quiet, theres your “great filter”. The few hundreds or thousands of years technological civilizations are “physical” is to short of a timespan for contacts to occur, they might happen, but VERY unlikely.

  • Alex Tolley October 20, 2015, 17:55

    @Steve White – well you saw the problem Wolfe-Simon ran into with the premature announcement of microbes that could replace phosphorus with arsenic, and the announcement of FTL neutrinos at CERN.

    We can speculate on CD, but it is important to have collected the necessary data to promote the ETI explanation in favor of natural explanations. When there is doubt, it makes sense not to claim something unlikely rather than something more likely.
    So while the data is not definitive, the default should be a natural explanation. This isn’t bias.

  • Rob October 20, 2015, 22:48

    Just wondering, IF we get lucky and the Allen Telescope Array found a signal or evidence of aliens, how soon would we know. I know they’d verify the hell out of it, for obvious reasons, but what would the procedure be? Would it leak out, how long after they found something before we’d know?

    I’m not sure if this is aliens, but if it is, my gut tells me we’re seeing either a remnant of their technology, that they perhaps abandoned long ago, or the other possibility, under partial initial construction.

  • tesh October 21, 2015, 1:45

    Daniel Högberg October 20, 2015 at 17:27
    I dont believe in Dyson spheres. Why would an advanced civilization build such an enormous structure when they probably have fusion power on a chip already? I believe large dead empty space habitats is something we may find though. Technology will develop so fast that in a timespan of only a few hundred years and up to around a thousand years, all technological civilisations will in the end be uploaded to their own artificial “game-worlds” / and or their version of our internet. Why would you not want live in world where you can do anything, be anything, and create anything. Why would you not want live in a world where only your imagination is the limit to what you can achieve? Thats why the universe is so quiet, theres your “great filter”. The few hundreds or thousands of years technological civilizations are “physical” is to short of a timespan for contacts to occur, they might happen, but VERY unlikely.

    Nailed!

    Fully agree.

  • Michael October 21, 2015, 3:01

    @Steven Ward October 20, 2015 at 17:19

    ‘I have a question, in the past few years, or forever I guess, has there been another instance of a bizarre astronomical discovery that has brought on so much attention and alien speculation? To me, this seems like the big one (not meaning that I expect this to be actual ETI).’

    There was the WOW! signal, but it may have turned out to be someone’s microwave ready meal!

    https://en.wikipedia.org/wiki/Wow!_signal

  • Michael October 21, 2015, 4:15

    I don’t think these features are close to the star as an orbit of around 50 days is implied by the second ‘maybe’ dimmed feature. If a large comet like object was that near a star not only would there be an infrared excess but also a light excess feature as light is reflected of this huge feature as it goes around the star, we just don’t see that in the light curve. IF it can dim a star by 22% it would reflect heavily as well so it must be further out.

    @Daniel Högberg October 20, 2015 at 17:27

    ‘I dont believe in Dyson spheres. Why would an advanced civilization build such an enormous structure when they probably have fusion power on a chip already?…’

    The star is a natural fusion reactor with no engineering required, although building such a massive closed structure may not be the best use of the materials, habitats with large light weight light collectors would be better.

  • Hugh October 21, 2015, 4:49

    Fascinating stuff. One thing I have not seen mentioned is the possibility of a ring-world-like use of mega-structures for beings to live on – i.e. they are not tenuous but solid structures with soil etc. The one at a 20 day orbit is rather hot and one at the 0.88d orbit (if not intrinsic stellar rotation) is hellishly hot but could be for power alone.
    Another possibility is that this is indeed a beacon to signal to others in the galaxy –
    ‘ hey – you are not alone!’. Admittedly a signal would have been better but maybe the race knew it was dying and so just wanted to leave a memento of its erstwhile presence.
    Finally, comets seem to be ruled out in that this 20 day cycle recurs too often, also for the large structures, indicating a close orbit – i.e. totally un-comet-like.

  • Hugh October 21, 2015, 5:00

    By the way – this is an old star: mist astronomers agree on that. It’s position outside the main plane of the galaxy, and remote from star formation regions, as well as its spectral class indicate a main sequence star about as old as the sun.
    One other thing: I agree a purely solar energy explanation is crazy as there are many better power sources. I am working on one myself that may be one of those to replace oil, solar etc. I can also think of several other ways to get massive power from ‘ the vacuum’. I’m also, like others, working on a possible FTL drive. First goal of such a drive could now be to send a robot probe to this star to see WTF is happening there.

  • kzb October 21, 2015, 7:16

    I personally don’t believe in the ET explanation.
    There is no IR excess, so whatever is causing these light dips is cold. A swarm of space habitats on this scale would radiate IR. They are orbiting much further out than the optimum for “solar”-power generation.
    If it was a space-semaphore system, it would’ve been designed to give an unmistakable signal, not a lot of random noise.

    There is not even any proof the supposed material is in orbit around this star. It could be intervening dust clouds.

  • Hugh October 21, 2015, 9:24

    @kzb (as I think you @’ed me)
    The lack of IR excess could confirm the thickness (optically anyway) of the structures. This might either confirm the habitat hypothesis or indicate ultra-efficient energy transformation technology, so that none escapes as waste heat. Recall that aliens who can build such things would have ways of preventing heat leakage.

    Who knows what alien logic would be behind a semaphore system? It might have reasoned that if they could keep the signal nice and (semi-) random, it would stand out as non-natural, as all natural satellites are strictly repeating.

    Also, these structures are indeed orbiting and not distant (IR excess!) gas clouds.
    This is shown by the 20 day period of even the large features, corresponding to an orbit of about 20 million km, well inside a Mercury orbit. Indeed, it’s this very superposition of the 20 day orbit on smaller and huge features alike that imply an ingenious mix of repetition and randomness. One scenario is a partially filled Dyson sphere or a Dyson formation that orbits and precesses and nutates in such a way that sometimes only a thinly filled section occludes the star while at other times large shapes may cause the giant dips. Indeed there could be a message here – by de-convolving the shape of the light curve, it may be possible to model the shape of the object. maybe it’s ironically star shaped (5 cornered) to have a star occlude a star :-). Or it’s a smiley or an image of an alien. That could explain the complexity of the light curve.

  • Harry R Ray October 21, 2015, 9:34

    PW: The EASIEST way for a K2 civilization to travel to another star is VIA THEIR OWN PLANET! i.e., build a “star”ship(star engine, Skhadov thruster) and move THEIR OWN STAR(over thousands to millions of years)to a new star, and go into orbit arounf that star. In past comments, I mentioned that we should focus on the M dwarf SECONDARY, NOT the primary, and that the “megastructures”(if that’s what thet ARE) may be the DISCARDED REMAINS of the “star”ship. kzb: Since the discarded remains of a “star”ship consists of mostly mirrors, they would reflect most of the visable light away, and NOT absorb ANY SUGNIFIGANT HEAT!

  • Alex Tolley October 21, 2015, 13:25

    Humans at least want to experience reality as well as fantasy. For example, they still climb mountains rather than simulated rock climbing in gyms or using VR.

  • tesh October 22, 2015, 1:09

    Alex Tolley October 21, 2015 at 13:25
    Humans at least want to experience reality as well as fantasy. For example, they still climb mountains rather than simulated rock climbing in gyms or using VR.

    Rock climbing, mountaineering and intact any outdoor pursuit is done by far less people than the use of social media, gaming or simply watching television. One has been around forever and the other for a blink of an eye and yet it has killed off the older pursuit.

  • tesh October 22, 2015, 1:45

    should add, the vanishingly small (particularly rock climber types) do not control the size of purse strings that are/will be required to build a mega structure around a star.

  • Hugh October 22, 2015, 6:14

    It could be a swarm of giant spaceships zipping round the star crying out YIPPEEE! in their curious alien argot. Well, either joy-riding youths or robots or even semi-normal interplanetary traffic. In fact, the clumps could be just a massive traffic jam! You’ve all seen a chain of endless vehicles on a motorway. Maybe something similar clogs up the space-lanes every now and then.

  • Michael October 22, 2015, 8:43

    mmmm…It looks like a planet in a ~25 day orbit possibly with moons cooking off, if you look at the last light dip you see an increase in light before it comes around to block light again which would be from reflectance of the star light off the comet like mass . It is in a tight orbit possibly with precession as indicated by the gravity dimming effect (moves over the equator), the large dimming is when it goes over the brighter pole. Maybe it is an icy moon cooking off after been pushed with its planet closer to the star by the other star.

  • Harry R Ray October 22, 2015, 9:46

    BEWARE: This is PURE SPECULATION, but, has ATA found “something”? PROBABLY NOT, but their latest communication as reported in the Boston Herald today was not consistant with previous ommunications immediately after observing Kepler 186f ang Kepler 452b. In those previous cases they announced “no signal detected” and that follow-up observations would be scheduled in their regular rotation. Whereas the Boston Herald stated that “observations were made last weekend and follow-up observations would be made in two weeks”. My take on this is that the Boston Herald left out that no signal was detected, WHICH IS WHAT WAS TOTALLY EXPECTED, because any verifiable signal would have to be from an extremely powerful transmission since the star is more than fourteen hundred light years away. HERE”S WHERE I GO WAY OFF ON A LIMB! The star’s OWN radio transmission(as opposed to pure background noise) would be powerful enough to be detected by ATA! Radio transmission from the star would pass through a cloud of comet dust UNIMPEDED but would be partially BLOCKED by a swarm of megastructures! Did ATA detect ANY signifigant dips in radio transmission from the star? Again, PROBABLY NOT, but if they did, it would probably take about two weeks to FULLY REDUCE THEIR DATA. That would be a POSSIBLE explanation for such a QUICK follow-up.

  • Michael October 22, 2015, 9:58

    @Hugh October 21, 2015 at 5:00

    ‘By the way – this is an old star: mist astronomers agree on that. It’s position outside the main plane of the galaxy, and remote from star formation regions, as well as its spectral class indicate a main sequence star about as old as the sun.’

    If the star was as old as ours it would be in a red giant/sub giant stage by now.

  • Michael October 22, 2015, 10:01
  • Alex Tolley October 22, 2015, 10:03

    @Tesh. So explain why there is such a huge global tourist industry if we can experience distant places by watching them on tv?

  • Harry R Ray October 22, 2015, 10:20

    UPDATE!!! Mystery solved(APPARANTLY)! The SETI institute did NOT indicate whether a signal was detected or not because they were NOT FOCUSING on any one particular wavelength(i.e., DELIBERATE COMMUNICATION)but, instead, a WIDE FREQUENCY RANGE, because they were looking for “megaleakage”. Obviously, it would take about two weeks to completely reduce their data. The two week follow-up may or may not(PROBABLY)indicate that they have already found something interesting in the raw data. Go see Dr Gerald Hart’s take on this at http://www.phys.org ASAP!

  • Harry R Ray October 22, 2015, 10:42

    Update to the update. Dr Seth Shostak saya that MORE RADIO ANTENNAS will be ADDED to the ATA next week to increase the sensitivity by a factor of TWO! Go to http://www.portaltotheuniverse.org for his complete commentary. The new ATA configuration should be FULLY OPERATIONAL in two weeks.

  • TLDR October 22, 2015, 12:23

    I think I’m seeing a false dichotomy, with this “natural” versus “alien” vibe.

    The variety of natural explanations also need to be evaluated carefully in light of evidence that is still being gathered. You could say “comets!” today and be embarrassed scientifically by the discovery of a set of brown dwarfs with ring systems next week.

    An open mind is always the preferred option.