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G-HAT: Searching For Kardashev Type III

A new paper out of the Glimpsing Heat from Alien Technologies search (G-HAT) at Penn State is packed with fascinating reading, and I’m delighted to send you in its direction (citation below) for a further dose of the energizing concepts of ‘Dysonian SETI.’ Supported by a New Frontiers in Astronomy and Cosmology grant funded by the John Templeton Foundation, G-HAT has been studying whether highly advanced civilizations are detectable through their waste heat at mid-infrared wavelengths, a tell-tale signature posited by Freeman Dyson in the 1960s.

We now have the highly useful dataset of some 100 million entries gathered by WISE, the Wide-field Infrared Survey Explorer mission, to work with. G-HAT researcher Roger Griffith, lead author of the paper on this work, went through these data, culling out 100,000 galaxies that could be seen with sufficient detail, and searching for any that produced an unusually strong mid-infrared signature. Fifty galaxies do show higher levels of mid-infrared than expected, necessitating follow-up studies to determine whether natural processes are at work or, indeed, the functions of an extraterrestrial civilization. But no clear signs of alien technology appear.

G-HAT’s founder, Jason Wright, points to the significance of this new scientific result:


Image: A false-color image of the mid-infrared emission from the Great Galaxy in Andromeda, as seen by Nasa’s WISE space telescope. The orange color represents emission from the heat of stars forming in the galaxy’s spiral arms. The G-HAT team used images such as these to search 100,000 nearby galaxies for unusually large amounts of this mid-infrared emission that might arise from alien civilizations. Credit: NASA/JPL-Caltech/WISE Team.

Wright refers to the work as a ‘pilot study’ that will help the researchers tune up their methodologies to separate natural astronomical sources from what could be waste heat from an alien civilization. The team found some curiosities within our own Milky Way, including one cluster of objects that WISE registers strongly, but that appears black in visible light telescopes. Co-investigator Matthew Povich (Cal Poly Pomona) believes this to be a cluster of young stars inside a hitherto undiscovered molecular cloud. Another local find: A bright nebula around the star 48 Librae apparently flagging a huge dust cloud. Both will doubtless receive scrutiny from astronomers even as G-HAT itself moves on to study its own best galactic candidates.

Griffith and Cal Poly Pomona undergraduate Jessica Maldonado studied the astronomical literature to find which of the most interesting objects turned up by the survey had previously been studied. About half a dozen had received no previous scrutiny, a fact that does not surprise G-HAT co-investigator Steinn Sigurðsson:

“When you’re looking for extreme phenomena with the newest, most sensitive technology, you expect to discover the unexpected, even if it’s not what you were looking for. Sure enough, Roger and Jessica did find some puzzling new objects. They are almost certainly natural astronomical phenomena, but we need to study them more carefully before we can say for sure exactly what’s going on.”

That there is much for G-HAT to do should be obvious from the fact that using the abundant WISE data in the mid-infrared is a new direction for SETI. There are those who would argue, as Michael Hart did back in 1975, that given the age of the Milky Way, we should be aware of other civilizations if they indeed existed. Hart believed that any galaxy will become colonized in a relatively short time when compared to the overall age of the galaxy. Either there is no spacefaring species in a galaxy, or the galaxy in question quickly fills up with them.

Nikolai Kardashev classified civilizations in 1965 on the basis of the energies they could use, a Type II civilization being one capable of using the power of its host star’s entire luminosity. This is the now familiar realm of the Dyson sphere, intercepting the entire output of its star. We then move to a Type III civilization, one capable of using the stellar luminosity of an entire galaxy. Hart’s argument was that the emergence of a Type II culture is shortly followed by Type III. If interstellar flight is common, we should expect many Type III civilizations. The paper notes:

If Hart’s reasoning is sound, then we should expect that, unless intelligent, spacefaring life is unique to Earth in the local universe, other galaxies should have galaxy-spanning supercivilizations, and a search for K3’s may be fruitful. If there is a flaw in it, then intelligent, spacefaring life may be endemic to the Milky Way in the form of many K2’s, in which case a search within the Milky Way would be more likely to succeed. It is prudent, therefore, to pursue both routes.

Type II civilizations in our own galaxy should be detectable, and we’ve looked before at searches for the waste heat of the Dyson spheres such cultures might create. Richard Carrigan’s work on this score has been pioneering (see Toward an Interstellar Archaeology as an entry into other articles on the topic that are in the archives). Carrigan used data from IRAS (the Infrared Astronomical Satellite, launched in 1983), deciding out of 11,000 sources that the best of the Dyson sphere candidates he found were reddened and dusty astronomical objects.

The G-HAT paper, the third produced by the group, also points to the searches for Dyson spheres by Jun Jugaku and Shiro Nishimura, whose work in the 1990s found no Dyson spheres around the roughly 550 stars they surveyed within 25 parsecs. James Annis conducted a search for Kardashev Type III civilizations in the late 1990s and found no evidence for them, but mid-infrared surveys like WISE give us far more data within which to conduct such a search.

Thus these early results from G-HAT point to deepening study as the team refines its methods to make them sensitive to lower waste heat levels from extraterrestrial technologies. The currently reported work tells us that none of the galaxies resolved by WISE in this study contain Type III civilizations that are reprocessing 85 percent or more of the starlight of their galaxy into the mid-infrared. And as mentioned above, out of 100,000 galaxies, only fifty show a mid-infrared signature that could be considered consistent with reprocessing more than 50 percent of the starlight.

These fifty point to the further investigations ahead. As does this::

We also identify 93 sources with γ > 0.25 but very little study in the scientific literature. Three of these sources are MIR-bright [mid-infrared] and red galaxies that are essentially new to science, having little or no literature presence beyond bare mentions of a detection by IRAS or other surveys.

Here γ refers to thermal waste heat emitted by an object (waste heat luminosity), which is expressed as a fraction of the starlight available to the civilization. The paper explains that for waste heat temperatures in the 100-600 K range, values of γ near 1 would indicate that most of the galaxy’s luminosity was in the mid-infrared (now we are talking about the waste heat of a Type III technology). Values near 0 would imply that the value of any alien waste heat was small compared to the total output of the stars in the galaxy. The paper continues:

Verification that the MIR flux in all of these galaxies is predominantly from natural sources (e.g., through SED [Spectral Energy Distribution] modeling across many more bands than WISE offers or spectroscopy) will push our upper limit on galaxy-spanning alien energy supplies in our sample of 1 × 105 galaxies down to 50% of the available starlight. In the meantime, these are the best candidates in the Local Universe for Type iii Kardashev civilizations.

The paper is Griffith et al., “The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. III. The Reddest Extended Sources in WISE,” Astrophysical Journal Supplement Series Vol. 217, No. 2, published 15 April 2015 (abstract / preprint). A Penn State news release is also available.


Comments on this entry are closed.

  • Eric S. April 16, 2015, 13:16

    There’s another alternative to the Type III’s not being present… perhaps they’re just REALLY, REALLY efficient. 25-30 years ago, I remember being in a trailer where the desktop computers would really heat that place up. Now, I’ve got more power in my iPhone. Multiply by a million years or so. If these civilizations master ‘six 9’s’ or more efficiency, all we’d likely see is… nothing.

  • Robert April 16, 2015, 13:36

    Based on work over the last two decades the assumptions of this strategy might be called into question. Specifically, the KIII civilization is supposed to leave heat signatures due to the unavoidable consequences of the Second Law of Thermodynamics. D.P. Sheehan and others have shown that it may not in fact be the absolute law we think. Essentially, if Sheehan is correct, a uniform bath of waste heat can be recycled into useful work endlessly which implies that an advanced super civilization able to use the energy of a whole galaxy could either be expanding at the rate that energy is produced (which seems impossible!) or capture the whole output equivalent of say one second and recycle it endlessly. In the first case such a super advanced civilization might be able to control the amount of waste heat to blend in with the cosmic background and thus hide their continually enlarging extra-galaxy civilization completely. In the second case they might allow the unused energy to escape completely also in effect hiding themselves by looking like a normal galaxy. Here is a link to the paper.


  • ljk April 16, 2015, 14:20

    Did they investigate NCG 5907, which seems to have a lot of red dwarf stars for a spiral galaxy:


    And see especially this article on the subject:



  • Tulse April 16, 2015, 14:50

    I agree, Eric S., and more specifically think that civilizations that technologically advanced may not be using stars as-is, as big balls of fusion that get their heat and light captured, but instead using their mass more directly, “disassembling” them to use in more efficient processes. By analogy, consider the difference between terrestrial fusion power scenarios than involved using fusion to produce heat to drive conventional steam-powered turbines, and aneutronic proposals that convert the moving plasma directly to electricity. That specific example is intended to only be an analogy, but I imagine that a starflight-capable civilization may have similar abilities to use mass more directly and efficiently than passively capturing the energy of naturally-occurring stars.

  • Matthew Barker April 16, 2015, 14:57

    I really can’t see how a Type III civilization could exist, unless there is faster than light communications. Without it two way communications would take centuries or more like thousands of years. During that time, a society would change, both in language, technology and societal norms. Almost impossible to keep a ‘civilization’ from collapsing.

  • FrankH April 16, 2015, 15:16

    It’s an interesting paper, but I think the concept is the SETI equivalent of a Spherical Cow.

    It’s possible that an advanced civilization would not need or want to build Dyson spheres; they may find other sources of energy, be AIs that require less energy than trillions of (albeit advanced) meat bags, etc.

    Maybe its time to reconsider what advanced civilizations would look like, rather than go by 50+ year old guesses.

  • Postman1 April 16, 2015, 15:34

    @Eric S. To extrapolate on your idea: Maybe the vast majority of galaxies are the homes of super-efficient type IIIs and those invisible galaxies are our missing dark matter. How would we ever know?

  • RobFlores April 16, 2015, 15:57

    Eric S, be that as it may, there will an intermediate period where a civ
    move from Type II to Type III, we should still be able to find traces of system
    engineering in some galaxies.

    The result from the study IMO, brought probability of the rise of another Sentient lifeforms in our Galaxy with the capacity to create an interstellar Civilization close to ZERO in the short term. If humanity were
    to slumber an wake up in 5o million years I doubt ETI would be dropping by to wake us.

    Very possible There is a variable(s) whose assumption is way off in the Drake equation, or even it has been omitted or perhaps even contemplated.

    Where could a large incorrect assumption lie?
    Biological, Social, or Planetary, Astrophysical Sciences.

    I place my bet on a confluence of all four that
    keeps destroying any lifeform with even the potential of a technological civ.

  • Ashley Baldwin April 16, 2015, 16:40

    Even a civilisation advanced enough to utilise the entire energy of is star is well beyond belching out crude infrared exhaust fumes . “Smoke”. Even today’s best computers are limited by their own heat production so to harness the energy of a galaxy such crude notions need leaving far behind -as they no better than what we do now bit with some extrapolation thrown in. With our current psychology any such civilisation would have self destructed long before. That’s the weakness inherent to Kardashev with its focus on technological advancement in isolation without thought to the necessary concomitant philosophical development necessary. It’s A Victorian attitude , all clanging and whirring Pistons allied to power . True transcendence , and that’s what we are talking about for the sorts of civilisation in question, will have a basis in understanding and manipulation of quantum theory – something we have just scratched the surface of and which is already showing almost unlimited possibilities . Everything and anything applies. Something we know about but are no where near understanding let alone harnessing . As with so many other things .It might as well be magic. To even discover the evidence of such an advanced civilisation we would have had to evolved immensly ourselves as a species let alone technologically. We talk of anthropomorphic thinking but worse than that is current anthropomorphic thinking. My best guess is that signs of advanced civilisations will be subtle and fleeting , not crude and energy based. Lasers , Death Stars ( with Really big lasers ) and tractor beams .All that I.R wasted and polluting the neighbourhood. We are complaining that heat production is bad for civilisation now , just on Earth , never mind a whole galaxy ! So much for recycling . No, much as applaud the thinking and effort here which is a big step up from the shouting into the abyss and listening for a reply we’ve been doing to date ,the best area to look is at the Quantum level as that’s where the smart money is already hinting the direction of truly advanced technology lies, not simply in crude manipulation of electromagnetic radiation to create different frequency fires . Maybe dark energy and mass are the signs of an advanced civilisation , maybe black holes are who knows ? If it was that obvious we would know by now.

  • ljk April 16, 2015, 17:02

    Putting a positive spin on this story. We don’t have 100,000 galaxies that seem to lack advanced alien intelligences, we have 50 which could!


  • James Stilwell April 16, 2015, 22:30

    Surely a galactic super-civilization has had to learn ways around Einstein’s rules of relativity regarding the speed of light…Such a civilization’s lifespan would be inhumanly extraordinary if successful while confined to sub light speed…Sagan’s idea for civilizations to migrate from system to system…suffer periodic societal collapses…and then regroup and continue is one brutish way forward…there might be a better way…but perhaps we are 10,000 years away from enjoying that kind of better way…Many of Einstein’s theories will hold for 1,000s of years…But one may die hard…

    From Scholarpedia, 6(10):8378. doi:10.4249/scholarpedia.8378
    revision #91049 [link to/cite this article]

    Bell’s theorem asserts that if certain predictions of quantum theory are correct then our world is non-local. “Non-local” here means that there exist interactions between events that are too far apart in space and too close together in time for the events to be connected even by signals moving at the speed of light. This theorem was proved in 1964 by John Stewart Bell and has been in recent decades the subject of extensive analysis, discussion, and development by both physicists and philosophers of science. The relevant predictions of quantum theory were first convincingly confirmed by the experiment of Aspect et al. in 1982; they have been even more convincingly reconfirmed many times since. In light of Bell’s theorem, the experiments thus establish that our world is non-local. This conclusion is very surprising, since non-locality is normally taken to be prohibited by the theory of relativity.

  • Dave Moore April 17, 2015, 0:53

    There is the assumption that a galaxy-wide civilization will use all the energy put out by all the stars.

    First off, if you have a civilization using all the resources with no margin, then this is a civilization on the brink of catastrophe and you not expect it to last long.

    The civilization may not use star light. You could have an Oort cloud civilization that uses Hydrogen fusion from the ice of cometary bodies to provide its energy. This would lead to no diminution of starlight but an IR excess in the order of a millionth of the total stellar output.

    There are many more possibilities than just building Dyson Spheres around stars, and a galaxy-wide civilization that produces an IR excess of one-millionth the galaxies output would be impossible to detect with today’s technology. So, a null result at the sort of resolution we currently have won’t really prove anything except take the most Los Vegas of civilizations off the board.

  • BRS April 17, 2015, 2:39

    RobFlores: “Where could a large incorrect assumption lie?
    Biological, Social, or Planetary, Astrophysical Sciences.”

    After no small amount of thinking about the big question of life in the Universe, I tentatively concluded that Biology is the most likely location of an “incorrect assumption.”

    Abiogenesis is a great unknown. We can’t place any good constraint on its likelihood. Beyond that, I think there is a step further along the evolutionary process toward intelligent life where we *can* place a meaningful, if subjective, constraint on the likelihood. That step is the transition from prokaryotic to eukaryotic forms (P-to-E henceforth).

    One might first ask whether or not such a P-to-E transition would be required at all for the continued evolution of biological complexity. If we examine the organisms on Earth, we find many independently evolved multicellular types, but all of the multicellular types wherein cells take on specialized roles in the larger organism are eukaryotic. Some bacterial and archaeal species are multicellular in the simple sense that they remain attached after cell division, but that is all.

    The P-to-E transition gave cells a toolkit for specialization and differentiation in the form of a flexible cytoskeleton and more refined control over gene expression. Critically, this toolkit arose *before* multicellularity. Because evolution is not a directed process, the fact that eukaryotic cells gained the capability to take on vastly different morphologies through simple changes in gene expression, the fact that they were pre-adapted with such an ideal toolkit for multicellularity, was just a coincidence of the development of life on Earth.

    The more one examines the architecture, the sub-cellular organization, the intra-cellular molecular trafficking and the regulatory apparatus of the eukaryotic cell the more extraordinary it seems. How did such gratuitous complexity, and indeed inefficiency, arise in the world of microbes where purifying selection is incredibly strong? There are also relics of many “big leaps” in the evolution of eukaryotic complexity. Endo-symbiotic events are one example.

    If the P-to-E transition was a fluke, then we may find abundant simple lifeforms but few complex lifeforms. There may be many “slime worlds” dominated by microbial mats, for instance.

  • Volucris April 17, 2015, 5:42

    Eric S., no matter how efficient the computations are, you can always do more of them, until you start to dim the stars. Not using all of the power supposes that a) there is some limit beyond which more computation becomes useless (I don’t think there is) b) building more computers is limited by some other factor, for example amount of available matter useful for making those ultra efficient computers.
    Maybe the aliens are just patiently sitting by their stars and waiting them to burn more hydrogen to metals to build more computers with :-)

    Well well, Robert what is it if not yet another http://en.wikipedia.org/wiki/Perpetual_motion#Patents. Looking at the abstract, the “turbine” was very probably delicately balanced, heated to high temperature, in a space where there needs to be some gas. It’s really hard to not set things in motion in those conditions (that is, it’s hard to make the system closed). A bit like the “Cannae drive” tests, if you blast kW’s of power to something balanced on a delicate scale in some atmosphere, it’s really hard to not make it move because of unevenly heating that atmosphere.

    Matthew, if they can’t effectively communicate, then maybe it’s wrong to call it “a” civilization, but it won’t preclude the galaxy being colonized. To me it wouldn’t sound too much of a stretch to creatures able to travel between stars sub-lightspeed to be able to live long enough to converse in ligthspeed communications.

    Ashley, even quantum computers need to erase bits of information, if for nothing else, then at least to to make way for new inputs, or they are bound to repeat computations in endless (albeit possibly very long?) cycles. Erasing bits of information always increases entropy (http://en.wikipedia.org/wiki/Landauer%27s_principle).

    All in all, I can’t quite see why advanced civilization would find capturing energy not useful, if for nothing else then to store it in some form (antimatter?) for future use, if stars are dishing it out at rate they need not to consume it.
    It’s a huge waste to let all of that energy just escape to the void. If there’s a reason for life to not rise to the occasion and make use of all the energy available to it, we sure haven’t seen empirical evidence for it in these backwoods of our galaxy.

  • John April 17, 2015, 7:11

    Having read a bit of the paper, the reasoning goes that if intelligence is rare – as the current lack of detection suggets – then it should be unchallenged in its home galaxy, and quickly spread to control all of it. If we detect no signs of type 3 civilisations, and continue to make no confirmed ETI detections, I see two obvious options: That either intelligence is extremely rare, or that intelligence doesn’t reach the stage 3 point. Does anything in the curent data favour one over the other ?

  • Al Jackson April 17, 2015, 9:34

    Looking for Kardashev civilizations by means of their consumption of energy always seemed like a zeroth-order approximation to me. Any civilization capable harnessing all the energy of a star or it’s galaxy must have mastered an ultra sophisticated instrumentality. Especially one that deploys a massive scale of star faring.
    One would suspect such a civilization would utilize such powers in very subtle and efficient ways.
    Someone rephrased Clarke’s Third Law this way,
    “Any sufficiently advanced civilization may not be indistinguishable from magic, it may just be indistinguishable.”

  • RobFlores April 17, 2015, 12:37

    Actually, there is the other possibility that was not mentioned in
    the original article, because the study type would not be able to spot it
    easily. We are categorizing by Power Use and maybe that is too restrictive.
    Why is it assumed that a very advance CIV would need the power output of
    an entire galaxy to exist? What If a civilization like that consists of only
    a few million entities, what the heck would they need with all that power?

    I think our main hope via this method of detection is for Type II+ Civs expanding into adjacent neighboring suns. After that they may decide
    the far off remote areas of their galaxy are best just explored. And settle into type III maturity. It just question of how long will they be an expanding Type II because I am pretty sure THAT will require a large amount of energy.

  • Erik Landahl April 17, 2015, 12:49

    Disheartening. Dismaying.

    Corporate-induced climate change and the catastrophic consequences it heaps on multicellular life will probably destroy our civilization within 100 years, barring a Manhattan Project to reverse global warming and cleanse the oceans of the cornucopia of pollutants.

    My grandchildren could be the generation that sees Humans extinguished. If the Sole Intelligence hypothesis is true, once Humankind goes dark, so does the universe . A million years of biological evolution and 50 millennia of developing a homo sapiens civilization will come to no purpose. 110 billion-plus intelligent lives will have been lived but rendered meaningless in the end.

    We advanced far from our bacterial infancy, but only far enough to engineer the extinction of the only intelligence in the universe.

    Depressing. Despairing. I hope the Sole Intelligence hypothesis is proven wrong.

  • Robert April 17, 2015, 15:12


    If your comments was responding to the Sheehan paper abstract I encourage you read the whole paper. There is no “turbine” which was only part of a thought experiment. Sheehan et al. implemented the idea with refractory metals and a diatomic gas. The system starts out at equilibrium at a (high temperature in this case but the principle is the same) ambient temperature and after time, one of the refractory metals gets hotter and the other colder than ambient. That is not supposed to happen and the data is not subtle being around 100K difference. Sheehan contends that the Seebeck voltages which where driving the thermocouple currents already challenge the current understanding of the Second law.

    In the following quote DP stands for Duncan’s Paradox after Duncan who originated the thought experiment designed to prove refractory metals could NOT have different rates for adsorption and desorption.

    “It might be argued that non-zero delta Phd [hydrogen dissociation power consumptions (Phd)] and Delta (TH2−He) [stationary temperature differentials such as those reported delta (TH2−He)] do not themselves require extensions to traditional thermodynamics because they have not been expressly harnessed to drive a heat engine (Fig. 1c). This argument fails on at least two counts. First, a standard formulation of the second law, one not requiring heat engines, stipulates that isolated systems (like the blackbody core) must relax to an equilibrium characterized by a single temperature. The experimental DP system did not; rather, it maintained two distinct temperatures that did not—and apparently could not—relax to a single temperature on account of its dual surface-specific reaction rates. Apparently, the DP system constitutes a stationary-state nonequilibrium. Second, the temperature differences in DP experiments generated Seebeck voltages that can drive currents—and did, through their thermocouple gauges—thus, were capable of performing work like a heat engine.
    In summary, Duncan’s temperature difference has been experimentally measured via differential hydrogen dissociation on tungsten and rhenium surfaces under high- temperature blackbody cavity conditions. We know of no credible way to reconcile these results with standard interpretations of the second law.”

  • Matthew Barker April 17, 2015, 16:37


    Even so, how long to live? to communicate one-way from one side of the Milky-Way galaxy, takes 100K years, to wait for a reply another 100k years. Extraordinary long lives as to which may or may not be possible. True, local stars systems would communicate together much easier, but further away from one another the more differences due to time lag of communications, would occur.
    I’m betting if we do find a Type III civilization, it would imply FTL communications is possible, if we do not find any then most likely there is no FTL communications possible. Any civilization that would be capable of colonizing an entire galaxy, I’m hazarding a guess, should have the knowledge and scientific capabilities to discover it.

  • RobFlores April 17, 2015, 16:44

    Humanity, will be fine, look at the Toba Event if you want to see what
    a catastrophe looks like, and there wasn’t a CEO involved that. Humanity is tougher than most believe it’s just that a rebirth of high technology that would take more centuries to recover.

  • Harold Daughety April 17, 2015, 16:48

    Having been somewhat and hopefully temporarily deactivated by the accumulated frailties of age, I have spent excessive time dozing in front of a muted TV. My mind seems to range far and wide in Dreamtime during these slumbers. I had a dream fragment of firing stone tipped arrows from a Uzi-styled weapon.

    I see in many of these discussions a stone age imperative behind yet to be developed advanced technology. Why does a highly advanced civilization need such unimaginable quantities of energy? Is the thinking related to our need for transportation fuel, or perhaps to our distant ancestors shivering by a smoldering fire? Those same ancestors appreciated a high birth rate because it offset an equally large infant death rate. They seemed to have been insecure living in anything larger than a kinship cluster possibly because of limited food sources. They had a drive to disperse perhaps to escape predation by their neighbors.

    If we cannot solve the social problems on earth, humanity will not survive long enough to develop space flight. If we solve these problems there is no survival value in leaving this stellar neighborhood. As to survival, it is significant only in an individual sense. We cannot “feel” the death of our species. I assure you, we will all die, and that is OK. It is also unavoidable.

    So what is a mature civilization? It seems to me that it is one that lives in harmony with the world that created them, and art has far more value than technology.

  • Harry R Ray April 18, 2015, 9:57

    What we may have here with these fifty is a bunch of KII’s, each one a DIFFERENT alien species (or the mechanical offshoots) co-existing BUT NOT CO-OPERATING with each other, and setting an UPPER LIMIT to the percentage of stars available for use to prevent any one KII from getting the upper hand on all of the others. I believe that the KEY statistic is the AVERAGE AGE of the fifty candidates. The reason I say this is, in our own 11 billion year old galaxy, biological evolution may proceed at such a slow pace that WE are among the FIRST species with the POTENTIAL to reach the KI threshold. If ALL of these 50 candidates are JUST SLIGHTLY OLDER (11.5 to 12 billion years old), it may say something about how far civilizations can advance where multiple spiecies ar present, and more ominously, if there are NO 12 billion PLUS year galaxies in the sample, that conflict for resources among multiple KII species will inevitably lead to the destruction of ALL intelegent species in ALL advanced galaxies.

  • Robert April 18, 2015, 14:30

    The very concept of the Alcubierre drive justifies the assumption that a super advanced civilization might have figured out how to at least send messages FTL if not themselves even if we humans can not resolve the issues involved. It is therefore reasonable to think KII and KIII civilizations could be coherent over galactic distances.

    On a related note, there is no end of folks who like to squash new ideas with talk of how hard, how impossible, how unlikely it is to ever amount to anything real. I call these folks Physics Cops and many like to build their reputations doing that. They think they are doing science a service and maybe occasionally they do but more often I fear they steer people away from taking new ideas seriously and thus hinder progress. One example is the recent controversy over the NASA results of the Cannea drive data. After the NASA article there was a spate of “debunking” articles attempting to shame NASA and shut down interest because the results appear to not fit into our well established paradigms. Similarly, Drexler’s work on Molecular Manufacturing was sidelined by those who wanted to redefine “nanotechnology” into whatever they were doing at the moment, Sheehan’s Second Law work is marginalized and Mills’ work on lower levels of the Hydrogen atom (with extraordinary technological applications) at BlackLight Power is consistently attacked by the editors at Wikipedia and several well known Physics Cops in spite of abundant evidence including several independent replications.

  • Alex Tolley April 18, 2015, 15:09

    The assumption of maximal energy harvesting is a very contemporary human thought. It may well be that advanced beings are much more energy frugal and do not need huge amounts of energy for their civs. They may even be transcendant from their material selves, like Clarke’s ancient, god-like aliens.

    KII’s I can see as making sense, but KIII’s.

    Note that on e KIII is achieved, growth stops unless more galaxies can be acquired.

  • ljk April 18, 2015, 17:38

    Alex Tolley said on April 18, 2015 at 15:09:

    “Note that on e KIII is achieved, growth stops unless more galaxies can be acquired.”

    Galaxies do merge. Perhaps some of those events are on purpose.

    And while this is of course fictional, the mere idea does give one pause:


  • Rob Henry April 22, 2015, 5:31

    BRS, do not underrate bacterial multicellularity.

    Firstly many modern cyanobacteria, display one terminally differentiated cell type (the heterocyst). This feature is in advance of even some metazoan lines (the most advanced of all the branches of eukaryote multicellular cell life), especially sponges. Stromatolites had far more special cell types, though we can only guess whether they derive from one species or a community of several.

    Secondly myxobacteria are very similar in all superficial respects to slime moulds and, typically, have larger genomes than them as if they are the more advanced form.

    Thirdly that purifying selection you site may be more a reflection of their typical remaining habitats AFTER they have been outcompeted by eukaryotes for slower growing complex niches (except that of slime mould) and subsequently forced into into places where the higher growth rate always wins.

    Fourthly, have you ever heard those arguments that the eukaryote nucleus has many archaic features not seen in bacteria or archaea? Have you ever asked yourself how primitive features could be retained until the eukaryote origin in the face of a billion years of purifying selection? It is almost as if some ‘slow and complex wins’ niches have always existed isn’t it.

  • ljk August 7, 2015, 13:19

    A Kardashev Type IV here?


    We are but bugs at this scale. Do/can bugs truly recognize artificiality on such a level?

  • ljk September 2, 2015, 15:04



    E. Zackrisson, P. Calissendorff, S. Asadi, A. Nyholm

    (Submitted on 10 Aug 2015 (v1), last revised 20 Aug 2015 (this version, v2))

    If advanced extraterrestrial civilizations choose to construct vast numbers of Dyson spheres to harvest radiation energy, this could affect the characteristics of their host galaxies. Potential signatures of such astroengineering projects include reduced optical luminosity, boosted infrared luminosity and morphological anomalies.

    Here, we apply a technique pioneered by Annis (1999) to search for Kardashev type III civilizations in disk galaxies, based on the predicted offset of these galaxies from the optical Tully-Fisher relation. By analyzing a sample of 1359 disk galaxies, we are able to set a conservative upper limit at 3% on the fraction of local disks subject to Dysonian astroengineering on galaxy-wide scales. However, the available data suggests that a small subset of disk galaxies actually may be underluminous with respect to the Tully-Fisher relation in the way expected for Kardashev type III objects.

    Based on the optical morphologies and infrared-to-optical luminosity ratios of such galaxies in our sample, we conclude that none of them stand out as strong Kardashev type III candidates and that their inferred properties likely have mundane explanations. This allows us to set a tentative upper limit at 0.3% on the fraction of Karashev type III disk galaxies in the local Universe.

    Comments: 13 pages, 3 figures, ApJ, in press. v.2: Typos fixed. Project homepage: this http URL

    Subjects: Astrophysics of Galaxies (astro-ph.GA)

    Cite as: arXiv:1508.02406 [astro-ph.GA]
    (or arXiv:1508.02406v2 [astro-ph.GA] for this version)

    Submission history

    From: Erik Zackrisson [view email]

    [v1] Mon, 10 Aug 2015 20:10:13 GMT (1517kb)
    [v2] Thu, 20 Aug 2015 08:03:31 GMT (1517kb)


  • ljk September 2, 2015, 15:24

    Move over Milky Way, elliptical galaxies are the most habitable in the cosmos

    September 2, 2015 by Pratika Dayal, The Conversation

    The search for extraterrestrial life is surely one of the most important tasks we humans can undertake. However, the cosmos is vast and we don’t really have any idea which bits of it are actually habitable.

    But what if we could target the search? We have built the first-ever “cosmobiological” model mapping the galaxies in our local universe to help us understand which ones are habitable. Surprisingly, we found that our own galaxy was not one of the top candidates.

    Full article here:


    To quote:

    Are we in the wrong galaxy?

    By all accounts, our Milky Way is a typical spiral galaxy of average size that roughly makes one star like our sun every year. Given that ellipticals are much more hospitable to habitable planets raises the interesting question of whether life here in the Milky Way is just a freak of nature.

    Or does the presence of life on at least one planet in the Milky Way imply that these big elliptical galaxies might be absolutely teeming with life?

    One drawback is that the nearest elliptical galaxy to the Milky Way, called Maffei1, is so far away that any radio signals beamed from this cosmic neighbour would take 9m years to reach us. Surveys such as the SETI (Search for Extraterrestrial Intelligence) that continually maps the skies for anomalous signals might one day detect such a signal in the far future, a call to us from our (not so) nearest neighbours.