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Why SETI Keeps Looking

How do you feel about a universe that shows no signs of intelligent life? Let’s suppose that we pursue various forms of SETI for the next century or two and at the end of that time, find no evidence whatsoever for extraterrestrial civilizations. Would scientists of that era be disappointed or simply perplexed? Would they, for that matter, keep on looking?

I suspect the latter is the case, not because extraterrestrial civilizations would demonstrate that we’re not alone, but because in matters of great scientific interest, it’s the truth we’re after, not just the results we want to see. In my view, learning that there was no other civilization within our galaxy — at least, not one we can detect — would be a profoundly interesting result. It might imply that life itself is rare, or even more to the point, that any civilizations that do arise are short-lived. This is that tricky term in the Drake equation that refers to the lifespan of a technological civilization, and if that lifetime is short, then our own position is tenuous.

The anomalous light curve in the Kepler data from KIC 8462852 focuses this issue because on the one hand I’m hearing from critics that SETI researchers simply want to see extraterrestrials in their data, and thus misinterpret natural phenomena. An equally vocal group asks why people like me are so keen on looking for natural explanations when the laws of physics do not rule out other civilizations. All I can say is that we need to be dispassionate in the SETI search, looking for interesting signals (or objects) while learning how to distinguish their probable causes.

In other words, I don’t have a horse in this race. The universe is what it is, and the great quest is to learn as much as we can about it. I am not going to lose sleep if we discover a natural cause for the KIC 8462852 light curves because whatever is going on there is astrophysically interesting, and will help us as we deepen our transit studies of other stars. The recent paper from Wright et al. discusses how transiting megastructures could be distinguished from exoplanets, and goes on to describe the natural sources that could produce such signatures. The ongoing discussion is fascinating in its own right and sharpens our observational skills.


Image: The Kepler field of view, containing portions of the constellations Cygnus, Lyra, and Draco. Credit: NASA.

Yesterday’s post looked at ‘gravity darkening’ as a possible explanation for what we see at KIC 8462852, with reference to conversations we’ve been having in the comments section here. Gravity darkening appears in the Wright paper, though not with reference to KIC 8462852, and is also under study in other systems, particularly the one called PTFO 8-8695. But its prospects seem to be dimming when it comes to KIC 8462852, as Wright explained in a tweet.

He went on to elaborate in yesterday’s comments section:

Gravity darkening might be a small part of the puzzle, but it does not explain the features of this star. Tabby’s star does not rotate fast enough to experience significant gravity darkening. That post also suggests that planets could be responsible, but planets are not large enough to produce the observed events, and there are too many events to explain with planets or stars.

The Wright paper lists nine natural causes of anomalous light curves in addition to gravity darkening, including planet/planet interactions, ring systems and debris fields, and starspots. Exomoons, the subject of continuing work by David Kipping and colleagues at the Hunt for Exomoons with Kepler project, also can play a role, with a sufficiently large moon producing its own transit events and leaving a signature in transit timing and duration variations.

We have examples of objects whose anomalies have been investigated and found to be natural, including the interesting CoRoT-29b, in which gravity darkening is likewise rejected. From the paper:

CoRoT-29b shows an unexplained, persistent, asymmetric transit — the amount of oblateness and gravity darkening required to explain the asymmetry appears to be inconsistent with the measured rotational velocity of the star (Cabrera et al. 2015). Cabrera et al. explore each of the natural confounders in Table 2.3 for such an anomaly, and find that none of them is satisfactory. Except for the radial velocity measurements of this system, which are consistent with CoRoT-29b having planetary mass, CoRoT-29b would be a fascinating candidate for an alien megastructure.

We can also assign a natural explanation to KIC 1255b, an interesting find because its transit depths vary widely even between consecutive transits, and its transit light curves show an asymmetry between ingress and egress. What we are apparently looking at here is a small planet that is disintegrating, creating a thick, comet-like coma and tail that is producing the asymmetries in the transit light curves. This is an intriguing situation, as the Wright paper notes, with the planet likely pared of 70 percent of its mass and reduced to an iron-nickel core.

We may well find a natural explanation that takes care of KIC 8462852 as well, and the large scope of the challenge will ensure that the object remains under intense scrutiny. Both CoRoT-29b and KIC 1255b are useful case studies because they show us how unusual transit signatures can be identified and explained. We also have to keep in mind that such signatures may not be immediately found because Kepler data assessment techniques are not tuned for them, as the paper notes:

…in some cases of highly non-standard transit signatures, it may be that only a model-free approach — such as a human-based, star-by-star light curve examination — would turn them up. Indeed, KIC 8462852 was discovered in exactly this manner. KIC 8462852 shows transit signatures consistent with a swarm of artificial objects, and we strongly encourage intense SETI efforts on it, in addition to conventional astronomical efforts to find more such objects (since, if it is natural, it is both very interesting in its own right and unlikely to be unique).

Thus we leave the KIC 8462852 story for now, although I would encourage anyone interested in Dysonian SETI to read through the Wright paper to get a sense of the range of transiting signatures that draw SETI interest. 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).


Comments on this entry are closed.

  • Björn Larsson October 27, 2015, 10:08

    Since the anomalies of KIC 8462852 only occurred when the Kepler telescope was pointing in the same direction, and no reasonable astrophysical explanation has been imagined, it is obviously an instrument issue. A dead pixel or something like that.

    SETI should keep looking (even at that star as well as at any star) because we probably know less than we think about what is out there. Consider subjectivity. We can’t measure it objectively even though we know that we have it. If subjectivity is a result of biological chemistry, then what else is also possible, which we cannot measure? Something which is neither objective nor subjective. And we are so proud of our intelligence, which is quite practical. But maybe there are other phenomena which are even more practical?

    We can’t know what to look for when we look for the unknown. Just keep looking!

  • Marshall Eubanks October 27, 2015, 10:45

    I think that we need to adjust our time horizons to the implications of billion-year-old civilizations (and I think that an implication of Fermi’s observation is that ETI, if they exist, are likely to be old). A billion-year-old civilization is likely to be aware of our existence (to survey the entire galaxy for biological systems would take much less than 1 billion years), and may well take some time before they communicate with new civilizations (if they even view us as at level worthy of communication with at all). So, the conventional SETI may take a long time to come to fruition (millennia, possibly) while “archaeological SETI” will involve distinguishing mega-engineering works from natural astrophysics, which is likely to take decades before people are convinced, even for fairly straight-forward cases (say, if KIC 8462852 really is some sort of engineering project).

  • John October 27, 2015, 11:04

    @ Bjorn Larson: The argument that the anomaly must be instrumental because only occured when the kepler telescope was trained on is the same as saying the Kepler telescope was the only telescope to see it…unless I’ve misunderstood you. It seems clear that the argument only holds weight if some other telescope with the same sensitivity as kepler has been pointed at this star and seen nothing – has this been the case?

  • Armando Gascón Lozano October 27, 2015, 11:39

    If somebody detects electromagnetic signals perhaps leaking from the activities in this star, if any, are they really going to tell the world?
    It would be the greatest scientific discovery of all times but the authorities may forbid them to make it public.

  • TLDR October 27, 2015, 12:25

    Agreed. It’s all about objectivity, or lack of it. That’s the origin of the “extraordinary” part of extraordinary claims.

    If it’s just a red flower versus a yellow flower, and nobody’s invested in it emotionally, then we can all be objective. But if it’s ALIENS, then of course we have to be on guard.

  • Björn Larsson October 27, 2015, 12:31

    Yes, it is so. Only Kepler has seen it, and only when it has been oriented (not “pointed” as I wrote above) in the same wave. One bad pixel, out of 95 million, could potentially explain it. Other telescopes, I think, have confirmed that there’s no IR radiation as would be expected from clouds of gas and dust which could cover large parts of the star. I think a boring technical little malfunction is the real explanation. There are too many problems with those 9 transiting anomalies in Jason’s paper to come to any other conclusion.

    Even if aliens are building Dyson spheres, which I think is a reasonable thing to do, it would be unlikely for us to catch them on the job half done with their pants down. The star would likely already be surrounded and dimmed uniformly. Since millions of years. But maybe a havoced abandoned one?

  • RobFlores October 27, 2015, 12:33

    Dysonian, engineering seems impractical to me. That is the main reason
    KIC 8462852 is probably planetary debris from comets/breakup of a planet.

    Just one detailed example:

    If we assume the ET build these structures, the time and effort required
    to complete them demands that it will be in use for at least a few million
    years. Unless the living space is just a continuous city you will have problems with maintaining any type of ecosystem/physical geography.
    Consider a simple 500ft modest hill. Consider that an ET civ may want to have vegetation and maybe fauna running about. The hill will be either a solid hill with a thick topsoil (unlikely as that is very heavy material) Or a hollow hill w/ Thick topsoil and base material below. If you have anytipe of irrigation via natural ‘rain’ or even ‘drip irrigation’, the top soil will move down slope. This will apply wherever there is even a small slope in the dysonian structure. Over the span of centuries you will need a system of
    replenishing that topsoil at the higher points of you artificial world. This
    is not a trivial issue, soil is heavy and you cant change its physical dynamics
    if you want to keep the soil alive. Even if you don’t have slopes on your
    dyson world, over the centuries there will still be points where the soil will misbehave and will cause a nice pastoral areas to have large dead spots, due
    to the differing properties of soil elements.
    On planetary bodies this is not an issue since base material in created
    at high sloping areas, at volcanic areas and tectonic mountain building, and
    is slowly turned to soil by colonization of microbes and plants. Much of the
    soil matter will eventually find it self as part of a shore line, then bottom of
    ocean, then recycled by tectonics.

    And you can go on with matters of Thermal regulation of the D-Sphere,
    Artificial gravity generation. And of course you have withstand the 42km/sec^2 gravity of a Sun like star at 1 Au, acting on your D-Sphere. (hint: you can’t use rotation)

    That is not to say ET would not build other artificial habitats
    For more modest Ring structures of a few hundred meters of diameter (standard space station) this would not be an issue since no one would pretend that said station is a substitute for a planetary surface and you don’t have to go through the charade of making natural biomes, thus making artificial grass/trees more palatable.

  • Björn Larsson October 27, 2015, 12:37

    Space debris escalation from broken mirrors could turn a neglected Dyson Sphere into an erratic dust cloud.

  • Bill Spillman October 27, 2015, 13:34

    Looking for massive engineering works is the best way to detect the existence (or prior existence) of extraterrestrial civilizations. If a civilization performs such an engineering feat, it will likely persist for a very long time, giving us a long window in which to detect its presence. SETI as it is currently carried out is trying to detect radio or optical signals in the probably very small window of time in which a civilization would produce them. This window is even closing for our own civilization after only a century or so given the advantages of spread spectrum communication techniques that are basically indistinguishable from noise if one does not have the key. To me, the current SETI programs are like the person who is looking for their lost car keys in the illuminated area under a street light in spite of the very low probability of finding them there. A careful search for the physical structures left behind by extraterrestrial civilizations has a much greater chance of success.

  • ljk October 27, 2015, 13:47

    TLDR said on October 27, 2015 at 12:25:

    “If it’s just a red flower versus a yellow flower, and nobody’s invested in it emotionally, then we can all be objective. But if it’s ALIENS, then of course we have to be on guard.”

    How shall we be “on guard” against an advanced ETI? If they have interstellar travel abilities right off the bat they could aim and drop planetoids or comets on Earth and wait for the dust to settle. Or they could just ram a single starship moving at relativistic speeds into Earth where the kinetic energy alone would sterilize almost all life on our planet. We would have no defenses against either of these methods of attack, especially the later one.

    And if the beings around KIC 12345678 are in fact building a Dyson Shell, the very structure could be used as a incredibly powerful beam weapon that could span the galaxy and destroy entire planets:


    And no, we have zero defenses against that.

  • ljk October 27, 2015, 13:48

    If there were even a reason to build a Dyson Shell and these beings evolved in any way as us, then it would be as a weapon. The same way our first serious rockets were made for destroying enemy targets, not exploring space.

  • Lepton October 27, 2015, 13:51

    Never understand the obsession on DS.

    Are we really sure that an K2 civilization thinks a DS is the best way to acquire energy and builds it? Don’t even want to talk about DS for habitation purpose.

    When I was a poor student, my dream car was BMW Z3, later when I could afford it, I didn’t want it anymore, because there were better alternatives. DS looks awfully like a Z3 to me.

  • Michael October 27, 2015, 13:52

    Very large structures can be built in space and they don’t need to rotate which would place stress on the structure, gas pressure would be enough to hold it up. You could have the 1g torus environments on the outside or just inside of this gas bag with maybe a water centre. Lights or if the sphere has transparent panels from their sun could be shine downwards into the sphere and when not in 1g environments you could have a few weeks in 0 g as a holiday for instance and food could be grown inside. So these structures could feasibly be seen in orbit due to reflection and transiting around there stars or any planet for that matter. Now the most likely shape to me would be a sphere as it has the most volume for materials used.

  • Michael October 27, 2015, 14:17

    I found this blog, it is decades old about how big a gas bag could be, it is quite staggering really!


  • Yruh October 27, 2015, 14:34

    With the 2 star systems with unusual transit signatures referenced, does that mean they blocked 20% of its star?

  • Paul Gilster October 27, 2015, 15:31

    Björn Larsson writes:

    Since the anomalies of KIC 8462852 only occurred when the Kepler telescope was pointing in the same direction, and no reasonable astrophysical explanation has been imagined, it is obviously an instrument issue. A dead pixel or something like that.

    The Boyajian paper examines instrument error carefully and finds no evidence of it. From the paper:

    The Kepler light curve for KIC 8462852 is unique, and we have thoroughly explored the raw data for defects/instrumental effects, which could cause the observed variations in KIC 8462852’s flux. We use the PYKE software tools for Kepler data analysis to check the data for instrumental effects. We check the following possibilities:

    • We checked that the same flux variations, i.e., the ‘dips’, are present in the SAP FLUX data set.
    • We verified that data gaps and cosmic rays events do not coincide with the dipping events, as they are prone to produce glitches in the corrected fluxes.
    • We verified at the pixel-level that there are no signs of peculiar photometric masks used in making the light curves.
    • We verified at the pixel level that the image light centroid does not shift during the ‘dipping’ events
    • We inspected light curves of neighboring sources and find that they do not show similar variability patterns in their light curves.
    • We determined that CCD cross talk and reflection cannot be the cause (Coughlin et el. 2014).
    • We verified with the Kepler team mission scientists that the data were of good quality.

    This analysis concludes that instrumental effects or artifacts in the data reduction are not the cause of the observed dipping events, and thus the nature of KIC 8462852’s light curve is astrophysical in origin.

  • Andrew Palfreyman October 27, 2015, 16:06

    “It might imply that life itself is rare, or even more to the point, that any civilizations that do arise are short-lived.”
    Or that quite simply we are early – perhaps even first within our galaxy. Perhaps the real alien fun en masse begins in another billion years or so.

  • Tom Mazanec October 27, 2015, 16:09

    What do we conclude if we make a prolonged radio search of Tabby’s Star and “hear” another WOW signal like the one from TYC 1220, 91,1 or those mentioned in Sagan’s Pale Blue Dot book? Since such signals have not been taken as confirmation of ETI before, would they now?

  • Jim Strom October 27, 2015, 16:34

    This C-D entry goes right to the heart of SETI efforts of any type.

    The Drake and Rare Earth equations allow for wide ranges of a possible present number of civilizations in the Milky Way (at planets where they abiogenically arose and evolved). Out of 200 billion stars, estimates range anywhere from 0 to tens of millions of such civilizations, depending on the assumptions. The range of the Drake/R.E. functions is ~8 orders of magnitude. On top of that general uncertainty, we might never understand the average amount of time it takes for intelligent life to originate, since we don’t understand the conditions and time needed for ETI to emerge.

    Also, the Drake/R.E. equations estimate likelihoods of an ETI at a locale where it abiogenically arose. They don’t estimate the chance of ETI _existence_ at a locale, which is different, since ETI could exist at a locale due to interstellar colonization, acceleration of the “I” (intelligence) from intentional spread of information (ala Contact), etc.

    The Drake/Rare Earth equations give no formal probability of observing ETI. But they do reflect some truths: there might be a possibility of finding ETI, and there might be nothing to find. So any valid conclusion of an ETI existence must come from observation of individual stars/planets, not statistical estimates. Keep applying the scientific method and see where it takes us, as is happening with Tabby’s Star and elsewhere.

    For instance, theories regarding infrared ETI signatures and technology to test those theories are on the horizon; see the Colossus Telescope. To me, though, the biggest obstacle is: where to point SETI-capable ‘scopes. Kepler’s 100,000 seems too few and too unreliable with respect to earth-like planets. My thought is that we won’t find ETI (if it is out there) until a second-gen Kepler that can better identify targets among the 200 billion candidates. Imagine a Kepler, but able to record spectrum data of hundreds of thousands of atmospheres, perhaps using an adaptive occulting mask of some sort (if only…). Something is probably needed to help look in the right places.

    About Dyson Structures, just a few conjectures about needs and means go a long way to support the theory. As far as needs, an advanced civilization could need that much clean and “free” energy for many purposes. If a civilization becomes sufficiently advanced, doesn’t continued existence become priority one? Dispersion and protection in the face of stellar-scale threats and distances require stellar-scale power. Also, star energy could be used for planet transformation, collecting raw materials, interstellar communication or travel, protection from natural or sentient threats, mining/extraction, maybe even tweaking one’s own star by reflecting energy back into it, etc.

    As far as means, a Dyson Structure for just energy collection need not be anything more than a mass of reflectors/collectors, possibly steerable. As others have said a Dyson Structure is just a problem of engineering, time, and resources.

  • Alex Tolley October 27, 2015, 16:50

    What I find instructive is that the most interesting possible (but unlikely) ETI sighting has come from an experiment far removed from the 50+ years old idea of looking for active radio signaling (or the more recent optical signaling). The detection of a megastructure is more akin to astronomical archaeology. It even makes more sense as a technique if structures last while civilizations may burn briefly like cosmic mayflies, leaving behind their artifacts.

    While full fledged Dyson spheres or swarms have so far not been found, especially for galaxy spanning KIII civs, I find the idea of such a search more appealing and allied with the search for the likely much more ubiquitous non-ETI life.

    I hope this episode, and the Wright paper particularly, galvanizes a search for ET artifacts in our galaxy, using techniques that we already have, as well as possibly adding directed search for signals from interesting targets.

  • Adam October 27, 2015, 17:01

    A Dyson Swarm is about the only feasible way to power relativistic space vehicles – especially lots of them. Given self-replicating Power-Sats the task only requires a few decades to complete if the doubling time is ~1 year or so. Thus any putative K-II Civilization isn’t all that far removed from ourselves in development time.

  • TLDR October 27, 2015, 17:08

    @ijk, I should have been clearer. I meant “the possibility of aliens”. In that case, one can be expected to lose objectivity. Something like the “possibility of discovering gold”.

  • IB October 27, 2015, 17:25

    Thank you Paul, from a long-term lurker, for your superb coverage of this fascinating topic.

  • Paul Gilster October 27, 2015, 19:56

    Thanks very much, IB! It’s always a pleasure to write for this audience. Thank you for being part of it.

  • P October 27, 2015, 20:36

    Somewhat related, and hot off the press:

    Exploring the A Cen system for planets:



  • Daniel Suggs October 27, 2015, 21:50

    I always been a science geek and reader of all things scifi, but following this growing plot has kept me on the edge of my seat like nothing else. Thanks for all the good updates. The Science channel had a five minute update tonight at 9:00pm from Tabby Boyajian herself that was also well done.
    I keep telling myself to slow down and smell the roses in life, but this makes me wish I could skip ahead, LOL!

  • Jason Wright October 27, 2015, 22:08

    Björn Larsson writes:

    >Since the anomalies of KIC 8462852 only occurred when the Kepler telescope
    >was pointing in the same direction, and no reasonable astrophysical >explanation has been imagined, it is obviously an instrument issue. A dead >pixel or something like that.

    This is not true. The first significant event occurred in Q1. The first whopper of an event in Q8, and the read fireworks started in Q16 and continued through a spacecraft roll into Q17. I think the event in Q3 is real, too, but I’m not sure:

    Q1 and Q17 were in one roll angle, Q8 and Q16 were in another. There is lots of low-level variability at every roll angle (zoom in and see). Since the events occur during different roll angles, this means entirely different detectors and readout electronics were used to measure these events.

    NASA has examined the individual pixels to see if one of them is the source of all of the variation. None of them is — all of the starlit pixels vary by the same fraction during all of the dimming events.

    Armando Gascón Lozano wrote:
    >If somebody detects electromagnetic signals perhaps leaking from the >activities in this star, if any, are they really going to tell the world?

    Of course! That’s why we look!

    >It would be the greatest scientific discovery of all times but the authorities >may forbid them to make it public.

    No “authorities” are looking over our shoulder. There’s no “SETI police”. There is no agency we have to call with a positive result. Besides, data from the Breakthrough Initiative will go public immediately, for the world to see, and be analyzed later, so there’s no way to go back and cover it up if something is discovered. Plus, you can’t hide a radio signal from space — and everyone’s looking at this thing now, anyway.

  • Hiro October 27, 2015, 22:27

    Does anyone know a paper whose author(s) used the Tracy-Widom distribution in SETI?

  • Björn Larsson October 28, 2015, 1:36

    @Paul Gilster
    Try to think! Don’t just blindly trust and obey everything authorities claim. Try to be a bit scientific instead.

    Boyajian, and the large crew of co-authors, fail to address the apparent fact that the anomaly is perfectly aligned with the telescope’s orbital period and only occurs when it is oriented in the same way. The anomalies only occur a few days after the telescope’s orientation has changed.

    The potential telescope issues they have checked are all fine. But they are irrelevant and their conclusion that it is an astrophysical phenomenon is unfounded and erroneous. Too bad that the star seems to have gotten the informal name “Tappy’s star”, one out of less than two dozen stars which have ever been named after an astronomer, because this is a piece of bad astronomy which neglected the obvious and jumped to false conclusions.

  • Björn Larsson October 28, 2015, 1:38

    It is most surprising that they ignore the strict periodicity of the anomalies, since transiting exoplanets is all about periodicity.

  • Marc Longoria October 28, 2015, 2:10

    I still don’t buy the cometary explanation. The dips are far too great to be comets and are also too erratic for a “megastructure” or even several artificial objects. We are more likely seeing a small cluster of rogue planets that are closer in distance to KIC 8462. Perhaps some of these rogue planets have even broken up. Since they are too far away from any star, it would also explain why we do not see IR.

  • Morris The Cat October 28, 2015, 5:01

    I cant exactly explain why, but it would be profoundly sad to think we are the only developed civilisation in our galaxy or the universe. With more research every day confirming how early life took hold on earth (now 4.1 billion years ago) it just seems almost impossible to think what happened on earth could not have happened on other planets with similar conditions.

  • Michael Spencer October 28, 2015, 7:09

    I’m reminded of an example given by Jill Tartar comparing the water contained in an ordinary tumbler to the volume of earth’s oceans. Such is the number of sampled stars by SETI. When stated so colorfully centuries pale.

    The universe is a very large place. And while the chances that we are not somewhere replicated in some manner approaches zero, the chances of meaningful intercourse similarly approach zero.

    It is heartbreaking.

  • Wojciech J October 28, 2015, 7:45

    “Or they could just ram a single starship moving at relativistic speeds into Earth where the kinetic energy alone would sterilize almost all life on our planet. We would have no defenses against either of these methods of attack, especially the later one. ”
    There is no reason to worry, such civilization would already be aware of planet like ours(as others have noted) and our biosphere, most likely civilization too, due to advanced hypertelescopes. If they would be interested in ending other civilizations they would have done so already.
    Alex Tolley:
    “While full fledged Dyson spheres or swarms have so far not been found, especially for galaxy spanning KIII civs”
    While Galaxy spanning haven’t been found, there are numerous Dyson Sphere candidates in our galaxy, that remain unconfirmed/inconclusive.


    I believe there are other astrophysical objects that some have speculated might be result of astro-engineering.

  • Wojciech J October 28, 2015, 8:00

    Also interesting information I found.

    The proposed Russian space observatory Spektr-M

    would have as part of its mission searching for traces 0f astro-engineering projects

    “The first sky FIR
    survey aimed at the detection and spectral measurements of astronomical objects was carried out on the
    IRAS satellite (InfraRed Astronomical Satellite). 250 thousand point-like sources were found. Results
    of the search for objects similar to the Dyson sphere, are reported in papers [67, 68] (Fig. 8); several
    objects were found, where a natural origin has not been still reliably proven.
    Important criteria are the spectral parameters and their comparison with the black body spectra.
    The spectral maximum determines the temperature. The spectral index in the long-wavelength part of
    a power-law spectrum is -2 for the black body and -3 and -4 for amorphous and metal dust particles,
    respectively, whose size is much smaller than a wavelength. Temperature, flux, form of the red part
    of the spectrum and a distance from the source can be used to estimate the size of the source, and to
    distinguish it from natural clouds of dust or stones emitting in the infrared (protostellar objects, old
    stars). To develop a reliable criterion of the search for the Dyson spheres, it is necessary to investigate
    in detail properties of natural sources, which can be accomplished by Millimetron.”

    Currently Russia plans to launch it in 2025, we will see how it goes.

  • ljk October 28, 2015, 8:59

    Humans often laugh at and mock what they do not understand. It is a reaction and a way to cover fear often enough:


    Whether aliens in any form do exist or not, it is a sign that humanity needs to start REALLY appreciating the fact that Earth is but a very small part of an immense and ancient reality, one that could swallow us up with hardly a pause if any. Think of the fact that supernovae happen all over the Universe all the time, no doubt destroying entire solar systems, yet the only people who tend to notice on this planet are a few dedicated astronomers.

    And yes, we have known intellectually for a long time just what a small part of the Cosmos we occupy, but most people still do not truly get it if they think about such things at all. We largely remain a collection of tribal mammals who remain in one spot with similar humans most of our lives.

    That is one of the good things which has come out of the discovery around KIC 90210, expanding human consciousness and waking people up to the possibilities out there – or ones that we could become some day ourselves.

    One possibility to help us become “cosmic citizens” is this idea I wrote about on Centauri Dreams in 2012. It is not perfect and I do not agree with their views on ETI, but it is a plan and something to build on:


    Further confirmation that we are part of the Cosmos and that on the fundamental level we are the same across the vastness:


  • ljk October 28, 2015, 9:13

    Tom Mazanec said on October 27, 2015 at 16:09;

    “What do we conclude if we make a prolonged radio search of Tabby’s Star and “hear” another WOW signal like the one from TYC 1220, 91,1 or those mentioned in Sagan’s Pale Blue Dot book? Since such signals have not been taken as confirmation of ETI before, would they now?”

    Why isn’t more attention – to say nothing of SETI observatories – being paid to the star system TYC 1220-91-1? I think it is an even better candidate than the Wow! signal of 1977 yet it is hard to find anything serious about it:



  • ljk October 28, 2015, 9:14
  • ljk October 28, 2015, 9:36

    If we do encounter ETI in space, I have my suspicions they will not be organic:


    And by the time we can conduct interstellar travel, neither will those explorers that originated from Earth. Machines are just more durable and efficient when it comes to space.

    This may explain another reason why current SETI isn’t working as originally thought because beings who do survive their cultural adolescence move on or create beings far more suited to the wider Cosmos. We just have to keep shifting our cultural paradigms to keep up with scientific knowledge and technological progress.

    As a prime example to keep it in the theme of KIC 87654321’s possibility of being a Dyson Shell, such structures may not be built to give organic beings like us a lot more room and energy but may actually BE beings themselves. The late Robert Bradbury was big on promoting this new paradigm.


  • PW October 28, 2015, 11:48

    I believe that the star system is undergoing natural processes, albeit perhaps unusual ones. I agree that it’s just interesting any way it turns out.
    So the main thing is to keep looking at it.
    So when is the next “Kepler” going to be available? And if we had another one up there, would it point at the same patch of sky? Probably not.
    I read about TESS. TESS should be launched in what, 2017? I was surprised that TESS is advertizing a 2 year life span. Hmmm, Kepler got 4 years, and that was insufficient to adopt to variable stars. 8 years, they said, would be needed.
    Then there is JWST. That will be a magnificent instrument…if all those complicated pieces unfold correctly in the harsh space environment after being shaken not stirred in a launch profile. And, everyone and their brother is going to be competing for time on JWST, certainly not just the exo-planet people.
    Perhaps the next President will simply shut NASA down altogether…

  • Alex Tolley October 28, 2015, 12:00

    @ljk. As you know I concur with this scenario. I think there are a lot more ramifications to explore than has been done to date that I am aware of.

    Artificial minds can be embodied in a wide variety of forms as they are no longer bound by biological development. How might that influence our SETI search?

  • Hiro October 28, 2015, 14:24

    @Alex Tolley:
    First, AIs don’t do colonizing around galaxies (collecting gold, platinum, diamond etc…), they are after the ultimate computation, more like trying to break the computational constraints of this universe etc….


    Advanced civilizations have goals which are unknown to us, hence it’s very hard to try guessing how to look for these specific behaviors in vast space.

  • TLDR October 28, 2015, 15:32

    @PW, several new ground-based instruments should make a difference as well. For radial velocity detection, I believe that ESPRESSO, due to see first light within a year, will start finding more small earthlike exoplanets in habitable zones around sun-like stars.

  • Alex Tolley October 28, 2015, 16:07


    First, AIs don’t do colonizing around galaxies (collecting gold, platinum, diamond etc…), they are after the ultimate computation, more like trying to break the computational constraints of this universe etc….

    You know that for a fact, do you? ;)

  • randomengineer October 28, 2015, 17:16

    >>Why isn’t more attention – to say nothing of SETI observatories – being paid to the star system TYC 1220-91-1? I think it is an even better candidate than the Wow! signal of 1977 yet it is hard to find anything serious about it:<<

    The theory presented in the above_top_secret article is rubbish unless there is evidence that the frequency in question just happens to be a magical one needed for radar used in planetary surveys or asteroid scanning. Showing the frequency[ies] we use for planetary scans and speaking to how that works and why would elevate that to a rational argument rather than 'I gots this here dubious theory.'

    re SETI and the probability of ET @ tabby's star

    I thought our luminaries like Hawking were fairly clear that being overtly visible to the universe may not be a good thing. We humans don't even have advanced tech at this stage yet even we can detect what appears to be a dyson swarm at 1500 ly. Clearly tabby's ETs don't listen to Hawking. Point is, if ETs have the same trepidation about overt visibility that hawking warns about, we would never know it. Conversely if tabby's star is ET central then maybe being visible ain't so bad after all. On the gripping hand if tabby's star is evidence of formerly alive ETs now long gone, then… uh – oh.

  • Steve Bowers October 28, 2015, 18:40

    ljk said: A slide presentation on the Dyson Asteroid Shell concept here:
    Heh heh- several of the images in that pdf are mine; always nice to see someone making good use of them…

  • Hiro October 28, 2015, 22:26

    @ Alex Tolley:

    It’s very hard to believe that some AI wants to marry semi-plastic (silicon) doll or wants to be a goldbug, I could be wrong though.

    Back to the topic, there is one interesting hypothesis about what advanced civilizations would do if they want to stay around for a long period of time.

  • Wojciech J October 29, 2015, 5:03

    “I thought our luminaries like Hawking were fairly clear that being overtly visible to the universe may not be a good thing. We humans don’t even have advanced tech at this stage yet even we can detect what appears to be a dyson swarm at 1500 ly.”
    We are overtly visible to our universe since our biosphere started, and became detectable by telescopes. Our own civilization is already on the verge of being able to detect surface biospheres in near neighbourhood and further within next 20-40 years. Any civilization advanced enough to travel between the stars would have no problem at all with detection of our planet and life on it-long before our own civilization even appeared.
    The talk about “being quiet” is simply based on lack of knowledge of what modern capabilities telescopes have and what they will be able to do in the future. Our biosphere, our atmosphere, our city lights-they are not quiet and are transmitting their visibility to the whole universe since their start.

  • Adam October 29, 2015, 6:27

    On the question of visibility, as raised by randomengineer, one response to the “Killing Star” scenario (i.e. the frightful preemptive strategy of ‘blast others with relativistic missiles before they can get you’) is that very energetic weapons have very visible effects and are pretty obvious in origin. Thus good neighbors refrain from smashing planets or boiling oceans with a Nicoll/Dyson laser.

    You never know who might be watching You, in the wild pre-K-III Galaxy…