Radio waves absent from the reputed megastructure-encompassed Kepler star?

Article written: 9 Nov , 2015
Updated: 23 Dec , 2015

Astronomers at the SETI institute (search for extraterrestrial intelligence) have reported their findings after monitoring the reputed megastructure-encompassed star KIC 8462852.  No significant radio signals were detected in observations carried out from the Allen Telescope Array between October 15-30th (nearly 12 hours each day).  However, there are caveats, namely that the sensitivity and frequency range were limited, and gaps existed in the coverage (e.g., between 6-7 Ghz).

Lead author Gerald Harp and the SETI team discussed the various ideas proposed to explain the anomalous Kepler brightness measurements of KIC 8462852, “The unusual star KIC 8462852 studied by the Kepler space telescope appears to have a large quantity of matter orbiting quickly about it. In transit, this material can obscure more than 20% of the light from that star. However, the dimming does not exhibit the periodicity expected of an accompanying exoplanet.”  The team went on to add that, “Although natural explanations should be favored; e.g., a constellation of comets disrupted by a passing star (Boyajian et al. 2015), or gravitational darkening of an oblate star (Galasyn 2015), it is interesting to speculate that the occluding matter might signal the presence of massive astroengineering projects constructed in the vicinity of KIC 8462582 (Wright, Cartier et al. 2015).”

One such megastructure was discussed in a famous paper by Freeman Dyson (1960), and subsequently designated a ‘Dyson Sphere‘.  In order to accommodate an advanced civilisation’s increasing energy demands, Dyson remarked that, “pressures will ultimately drive an intelligent species to adopt some such efficient exploitation of its available resources. One should expect that, within a few thousand years of its entering the stage of industrial development, any intelligent species should be found occupying an artificial biosphere which completely surrounds its parent star.”  Dyson further proposed that a search be potentially conducted for artificial radio emissions stemming from the vicinity of a target star.

An episode of Star Trek TNG featured a memorable discussion regarding a ‘Dyson Sphere‘.

The SETI team summarized Dyson’s idea by noting that Solar panels could serve to capture starlight as a source of sustainable energy, and likewise highlighted that other, “large-scale structures might be built to serve as possible habitats (e.g., “ring worlds”), or as long-lived beacons to signal the existence of such civilizations to technologically advanced life in other star systems by occluding starlight in a manner not characteristic of natural orbiting bodies (Arnold 2013).”  Indeed, bright variable stars such as the famed Cepheid stars have been cited as potential beacons.

The Universe Today’s Fraser Cain discusses a ‘Dyson Sphere‘.

If a Dyson Sphere encompassed the Kepler catalogued star, the SETI team were seeking in part to identify spacecraft that may service a large structure and could be revealed by a powerful wide bandwidth signal.  The team concluded that their radio observations did not reveal any significant signal stemming from the star (e.g., Fig 1 below).  Yet as noted above, the sensitivity was limited to above 100 Jy and the frequency range was restricted to 1-10 Ghz, and gaps existed in that coverage.

Fig 1 from Harp et al. 2015 ( indicating the lack of signal detected for the Kepler star (black symbols).

Fig 1 from Harp et al. (2015) conveys the lack of radio waves emerging from the star KIC 8462852 (black symbols), however there were sensitivity and coverage limitations (see text).  The signal emerging from the quasar 3c84 is shown via blue symbols.

What is causing the odd brightness variations seen in the Kepler star KIC 8462852?   Were those anomalous variations a result of an unknown spurious artefact from the telescope itself, a swath of comets temporarily blocking the star’s light, or perhaps something more extravagant.  The latter should not be hailed as the de facto source simply because an explanation is not readily available.  However, the intellectual exercise of contemplating the technology advanced civilisations could construct to address certain needs (e.g., energy) is certainly a worthy venture.

26 Responses

  1. Member
    Ray Bingham says

    How far away is this star. Remembering that at galactic distances which are measured in light years the light we see from the star must be from that star a long long time ago. What then is really happening there now. They certainly are far past the stage we see when we look at it. Are they now traveling across the galaxy, and in what direction. It must by now be a very advanced civilization if it was so far advanced so long ago.

  2. BrianFraser says

    The key words are “occluding starlight in a manner not characteristic of natural orbiting bodies”

    This star system is probably undergoing planet formation, specifically the bombardment phase.

    A theory of planet formation must account for:

    1. The existence of very large chunks of material (asteroid size) that are flying around in chaotic orbits, smashing and bashing into each other over long periods of time.

    2. The fact that some of this material has come to us as meteorites. When the metal types are cut open, polished and etched, so-called Widmanstatten patterns become visible. These indicate slow cooling.

    3. When the stony types are cut open, round “chondrules” are evident, suggesting that the material cooled in a zero g environment.

    None of this is consistent with the “condensation from dust” hypothesis. Rather, it is suggestive of a supernova explosion. The debris was not blown fully into interstellar space, but is instead coming back together under its own gravity. The production of a white dwarf star (ultradense) is apparently part of this process.

  3. Richard Kirk says

    Before we talk about this as though it was a Dyson Sphere, just remember there are a lot of mad objects out there. My favourite still is this one…

    Supposing you saw another star being eclipsed by the carbon spiral. You would see the brightness of the star go up and down in a sort-of periodic fashion, a bit like this thing.

    • gopher65 says

      Oh look, it’s back from the days before Phil decided his words were too good for the masses, and needed to be paywalled so that his once a week posts about Doctor Who could eliminate the need for him to have a real job!

      (I’m clearly not bitter about his betrayal.)

      • mewo says

        For me it was when he joined the conga line of charlatans misquoting Tim Hunt on twitter. Still hasn’t retracted or apologised to my knowledge.

  4. FarAwayLongAgo says

    It’s just a slight malfunction of the telescope. Anomalies only occur (every other time) when the telescope is turned the same way. It turns 4 times per orbit to keep its sunshield towards the Sun. Nothing to see, as SETI has confirmed.

    • mewo says

      Nah, your ‘dodgy pixel’ theory doesn’t work.

    • Random Sample says

      The Kepler telescope is located in a heliocentric orbit trailing the Earth. The Kepler team has checked its images of other stars when it was detecting changes in brightness of this individual star, and its images of the other stars were unaffected. I think that pretty well rules out your theory, FarAwayLongAgo.

      • FarAwayLongAgo says

        Why do the anomalies only happen when the telescope is turned the same way, in the same quarters of its orbit? Compare the probability of a telescope related cause, with the probability of the astrophysical explanations proposed. Uniquely in one out of 160,000 stars observed.

      • Random Sample says

        First, I must ask where you got the information that this was always observed during the same quarter of Kepler’s orbit. Second, I don’t think it is in any way unlikely that, out of 160,000 stars, only one would have a civilization capable of building megastructures that just happen to pass in front of the star from Earth’s perspective.

      • FarAwayLongAgo says

        I simply match the dates in the link below, with the day-numbers given in the light-curve diagrams published.

        The first in time and third in strength, anomaly (<1%) is a week too early, but I suspect that the telescope was turned the same way already then, as it was prepared to get into regular service. I don't know the details, and Tabby's et co paper doesn't deal with them.

        I simply saw the obvious periodicity in the diagram and counted the days to be nearly aligned with Earth orbital period. But Kepler orbits a bit slower, and it seems to fit that even better, when looking at the schedule.

        And speculating, as one should, I think that a civilization that managed to build a Dyson Sphere would have no problems traveling to other stars. Beaming it's Sun's energy to a solar sail, or something. Dyson Sphere's should come in groups built during millions of years, with only thousands of year's travel time between near stars to exploit. But the signal looks much more like an electronic malfunction than anything transiting, artificial or natural. There are 95 megapixels on that CCD.

  5. sangos says

    Try the VLA. Try the extended arrays. Try Ariciebo. If all fails then either our gear is not sensitive enough, or aliens use non radio comms, or the signal fades before it reaches earth, or the aliens are dead, or its not aliens, or……….we clearly have limited tools to resolve this mystery!

    • Smokey says

      “……….we clearly have limited tools to resolve this mystery!”

      At the very least, THEY do. For example, much of Earth’s satellite communications happens at Ku & Ka frequencies waaay above 10GHz. And why are we limited to 100MHz carriers? What about SSMA carriers which might span GHz? Even we Terrans can (and do!) do that. And what about the fact that our own communications are directed/colimated, and thus not easily seen if not pointed directly at the observer? Would we not expect a culture capable of space-faring mega-structures capable of even greater capability/efficiency, i.e., less power used via tighter beaming?

      Honestly, this was a long-shot under the best possible circumstances, so the absence of evidence in this case (as found by SETI) certainly does NOT provide proof of absence (of ETI). It would not surprise me at all if such signals … even IF they were visible to the equipment being used … would simply have been lost in the background noise of the star itself and the intervening void between us at the frequencies observed.

      • marcbyron says

        Why would we think that an advanced species would be using radio waves for communication? How about Neutrino transmissions? They are far more effective and definitely more likely for a civilization that’s thousands of years more advanced than we are

      • Smokey says

        An excellent point, marc.

        My point was that even if they were using technology with which we were familiar, detecting it with the equipment SETI used was already unlikely, to say the least. If the proposed civilization A) exists, and B) is using even more advanced methods such as the one you’ve suggested, that just makes detection even more implausible.

        While we’re on the subject, I’m not sure how effective neutrino-based comm systems would be, as their most desirable trait — the fact any signal so transmitted would pass through just about any amount of ANYTHING (cf. — tends to make them really hard to detect/manipulate. Regardless, they certainly won’t get found by the Allen Array!

      • FarAwayLongAgo says

        One reason could be that we now soon reach a ceiling of development. Some philosophical cosmologists actually seem to imply that, as they say that maybe everything is discovered now soon, with Higg’s boson and the CMB. No surprises for cosmology anymore. JWST and other super telescopes might nail that coffin if true, within just a decade or two. Fantastic times right now. Then physics could maybe not keep developing radically, and we get stuck. Neutrino communication remaining outside of usability for us. But I don’t really see that horizon yet.

      • Member
        Pete says

        Far, you sound just like the old saw “Everything that can be invented has been invented.” (Falsely attributed but cute nonetheless.) Do you really believe there is nothing more to be discovered? Should the CERN folks who are trying to take quarks apart stop their work?
        Man, I’ve known some pessimists but you have really surprised me.

      • Random Sample says

        I have to agree with Pete. This was a common attitude among some scientists and many engineers during the 19th Century – right up until relativity and quantum mechanics came along. If you really think we are on the verge of explaining everything about everything, try explaining: (1) the fact that relativity and quantum mechanics are inherently incompatible, (2) dark matter (or the effect that we attribute to dark matter, anyway), and (3) the accelerating expansion of the universe (a.k.a. “dark energy”). None of these phenomena can be explained by invoking what we know about matter, spacetime, electromagnetism, or the other three fundamental forces of the universe.

      • sangos says

        There is only one path to figure this out. We need to directly image this star system with enough resolution to see whats the deal.

      • Random Sample says

        Hey, yeah, no problem. Easy as pie. Wonder why no one else suggested this?

  6. Paul Gracey says

    As clever and compelling idea as the Dyson Sphere was in its time, I liken it to Lord Kelvin’s computation of the soon to end life of the sun. He understood the sun as a chemical fire, a phenomena with parameters he knew very well as it was the age of steam power. Once we understood that it was nuclear fusion, any worries that it would consume all its fuel quickly, evaporated. Dyson, too, understood his field of inquiry in the age of nuclear power. Both steam power plants and the nuclear variation are of poor efficiency when considered over their life cycles. Our lighting systems that depended upon them were similarly inefficient. Our binge on that sort of profligate energy use was in full swing at that time, so I do not blame Dyson for his conjecture, but I do blame the rest of us for not understanding the inanity of its implications.
    Should this apparently inconsistent ‘signal’ indicate the partial construction of such a sphere it may also indicate that a long dead civilization could not cope with its energy needs in a finite star system rationally.

  7. Member
    Aqua4U says

    Dan Majaess, it’s been too long! Welcome back…

    I like an idea I read about at Science Daily that chatted up a device that is able to ‘teleport’ a magnetic field via a form of quantum entanglement. Keyword here is ‘spintronics’. The ‘teleported’ field has one pole or is a monopole field. Imagine having a quantum entangled monopole antenna for a SETI survey?

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