≡ Menu

SETI: The Black Hole Alternative

Our speculations about advanced civilizations invariably invoke Nikolai Kardashev’s scale, on which a Type III civilization is the most advanced, using the energy output of its entire galaxy. Given the age of our universe, a Type III has seemingly had time to emerge somewhere, yet a recent extensive survey shows no signs of them. All of this leads Keith Cooper to consider possible reasons for the lack, including societies that use their energies in ways other than we are imagining and cultures whose greatest interest is less in stars than in their galaxy’s black holes. Keith is an old friend of Centauri Dreams, with whom I’ve conducted published dialogues on interstellar issues in the past (look for these to begin again). A freelance science journalist and contributing editor to Astronomy Now, Keith’s ideas in the essay below help to illuminate the new forms of SETI now emerging as we try to puzzle out the enigma of Kardashev Type III.

By Keith Cooper

keith2

It’s not often that SETI turns up with a result that can be considered far-reaching, but the initial results from the Glimpsing Heat from Alien Technologies (G-HAT, or ‘Ĝ’ for short) survey, which Paul wrote about in April (see G-HAT: Searching for Kardashev Type III), fit the bill. Using publicly-available data from NASA’s Wide-field Infrared Survey Explorer (WISE), astronomers have searched 100,000 galaxies for anomalous infrared emission that could be an indication of heat emitted from vast energy collectors and their consumers encircling myriad stars.

The idea is that as a civilisation grows more technologically advanced, its hunger for energy increases. Civilisations could build Dyson spheres to capture all the energy from their star; as they spread to other stars, they may build Dyson spheres around them too. After perhaps a few million years, they spread amongst all the stars in their galaxy, building Dyson spheres around every one of them. The Dyson spheres grow hot and re-radiate some of that thermal energy away as mid-infrared radiation. Consequently, a galaxy that has been completely filled with intelligent, technological life should completely alter the light coming from that galaxy, pushing it more towards the infrared.

Yet the search of 100,000 galaxies has not turned up even one single galaxy that has the signature of a civilisation harvesting the energy of an entire galaxy of stars. This would be analogous to a Kardashev Type III civilisation, referring to the scale developed by Soviet astrophysicist Nikolai Kardashev to measure a civilisation’s energy usage. He based his scale on the Milky Way, so a Type III civilisation resident in our own Galaxy would have a total output of 1036 watts; an analogous civilisation in another galaxy may have a higher or lesser energy output as a consequence of the differences in the number of stars between galaxies, but for the purpose of this article we’ll describe them as Type III too.

Going down the scale, there are Type II civilisations, which harness the energy of a single star, which in the case of the Sun would be 1026 watts; again, for other stars, this will vary. Meanwhile a Type I civilisation is able to collect all the energy available to it on its home planet, which for the case of Earth is about 1016 watts. Carl Sagan further developed the scale, adding graduations between the types. Human civilisation comes in at just 0.7 on the Kardashev–Sagan scale.

Kardashev_civilization_type_III

Image: A Kardashev Type III civilization would be able to exploit the energy of all the stars in its galaxy.

The point of all this is that the G-HAT result throws a spanner in the works, by finding no Type III civilisations anywhere. It demands that we look again at the Kardashev scale and the assumptions that it makes.

Indeed, at first glance it may seem like bad news for SETI. After all, the Universe is very old, as are the galaxies that inhabit it. There should have been plenty of time for a civilisation, or more than one civilisation, to colonise and collect the energy from every star they come across in their galaxy, so why haven’t they?

There are a couple of reasons why the apparent absence of Type III civilisations might not be bad news for SETI. First, although there may be no Type III civilisations out there, Jason Wright of Penn State University, who founded the G-HAT project, says we shouldn’t yet discount civilisations below that level.

“This search would have only found the most extreme case of advanced civilisation, one that had spread throughout its entire galaxy and was capturing and harnessing one hundred percent of the starlight for its own purpose,” he told me when asked about G-HAT’s findings. “Kardashev 3.0 is the most extreme possible case, but there could still be a Kardashev 2.9, where only ten percent of the starlight is being used, or 2.8 where only one percent of the starlight is being used. So we’ve ruled out 3.0, but we’ve not even gotten down to 2.9 percent yet, much less something smaller like 2.5, that could be very hard [to detect].”

So far, the G-HAT analysis has found no galaxies with an infrared emission signature suggesting more than 85 percent of the starlight is being converted into thermal radiation. Fifty galaxies in the survey did stand out as having greater than 50 percent of the starlight being transformed into infrared emission, and follow up work on these is the next step, but to confuse matters there are also natural phenomena that can mimic this infrared emission, chiefly interstellar dust. Starburst galaxies, which are experiencing a severe bout of star formation, produce substantial amounts of dust. This dust absorbs starlight, heats up, and re-emits at mid-infrared wavelengths. The fifty galaxies with high infrared emission are quite possibly starburst galaxies (one of them, Arp 220, certainly is).

starburst2

Image: Messier 82 (top of image), seen here with the spiral Messier 81, is a starburst galaxy, meaning it is currently forming stars at an exceptionally high rate. This huge burst of activity was caused by its close encounter with Messier 81, whose gravitational influence caused gas near the center of Messier 82 to rapidly compress. This compression triggered an explosion of star formation, concentrated near the core. The intense radiation from all of the newly formed massive stars creates a galactic “superwind” that is blowing massive amounts of gas and dust out perpendicular to the plane of the galaxy. This ejected material (seen as the orange/yellow areas extending up and down) is made mostly of polycyclic aromatic hydrocarbons, which are common products of combustion here on Earth. It can literally be thought of as the smoke from the cigar. Credit: NASA/JPL-Caltech/UCLA.

However, the analysis has not yet looked at galaxy type. “That would be an excellent next step, to separate out the galaxies that have a lot of dust and which we would expect to be giving out a lot of heat, from the ones that have hardly any dust and shouldn’t be giving out any mid-infrared radiation at all,” says Wright. He is referring here in particular to dust-free elliptical galaxies; if one was found to have infrared emission that might be relatively low compared to a starburst galaxy, but was high for an elliptical galaxy, it might signal something unusual.

It would seem then that there could still be life in these galaxies, life that could be technological, star-faring and energy consuming – we’ve barely scratched the surface. And yet, one pertinent question still remains unanswered: where are all the Type III civilisations?

The G-HAT results tell us that Type III civilisations do not exist (or, at best, have a frequency of less than one Type III civilisation per 100,000 galaxies). This is why I suggested at the top of this article that this result is far-reaching – we now know something that we didn’t know before, namely that civilisations do not seem to reach Type III status. This, though, is the second reason why the result is not necessarily bad for SETI. Think of it this way: the Kardashev scale has become part of the SETI furniture since it was first proposed in 1964. The G-HAT result forces us to question our assumptions about the Kardashev scale and broaden our thinking about extraterrestrial civilisations to encompass other ideas.

Of course, any model has assumptions inherent in it. So let’s assume that technological extraterrestrial civilisations do exist in the Universe and that they are far older than we are (dictated by the fact that the Universe is very old, and there has been plenty of time for civilisations to have gotten well ahead of us before there was even life on Earth); these seem fairly safe assumptions for this kind of discussion. Somewhere along the line they are falling off the Kardashev trajectory. Why?

I want to flag up three possibilities. They may not be the only possibilities. We’ll discount for now the notion that civilisations could destroy themselves – once they become interstellar the task of destroying themselves becomes inordinately more difficult, so for our purposes we’ll assume they at least reach the stage of interstellar flight. On what alternate trajectories away from the Type III destination could their evolution take them?

1. They fail to colonise all the stars

This hypothesis would to an extent fit with the G-HAT observations – extraterrestrial civilisations haven’t built Dyson spheres around 100 percent of the stars in any of 100,000 galaxies, but the result leaves room for them to have done so around a smaller percentage of stars. Perhaps the best reasoning as to why an advanced civilisation possessing the ability for interstellar travel would fail to colonise an entire galaxy is Geoffrey Landis’ percolation theory.

Landis makes the assumption that interstellar travel is short haul only. We might be able to make direct flights to alpha Centauri or epsilon Eridani, but anything much beyond that, moving at just a small fraction of the speed of light – let’s say between 5 and 10 percent – is going to take far too long. So instead, civilisations will hop across the cosmos via the stepping stones of the colonies they set up along the way. For example, imagine three worldships leaving the Solar System for pastures new: let’s say alpha Centauri, epsilon Eridani and Barnard’s Star, all of which are relatively nearby. They set up colonies there, begin building Dyson spheres and perhaps, after a few centuries, those colonies are ready to send out their own pilgrims to new stars further afield, which then found new colonies and, after a few centuries, they too head out on voyages of colonisation, and so on. Over the millennia, humankind’s reach gradually telescopes outwards.

What Landis realised was that not all colonies will seed daughter colonies. The drive to go further will not exist in every colony; cut-off from their mother-world, Earth, by time and space, they build their own cultures, their own histories, and face their own, perhaps unique, challenges. Some will be content to not explore further. Others may destroy themselves, or exhaust their resources before they can build a Dyson sphere. In some cases, there may be no worlds in nearby systems suitable for colonisation. The consequence of any of these possibilities is that some colonies will become dead ends and will fail to colonise further.

To model this, Landis assigns a probability of being colonised to a given planetary system. If that probability is above a critical threshold, then it will be colonised. If it is below the threshold, colonisation of that system will not take place. Eventually, all colonies may result in dead ends, ultimately limiting the extent to which that species colonises the galaxy it exists in. Even if there is one line of colonisation that does continue for a time, there will be voids all around it, left empty by the dead end colonies. A civilisation would struggle to reach Type III status in this fashion.

Landis’ percolation theory is not without its critics. Robin Hanson of the University of California, Berkeley, points to economics and argues that the only way to survive would be to keep up with a colonising wave because the wave would consume all the resources, leaving little of value behind it, a kind of ‘burning of the cosmic commons’ as Hanson describes it. Jason Wright is also critical, arguing that the proper motion of stars would eventually allow active colonies to spread to other stars. For what it’s worth, Landis agrees that the percolation model is not without its problems.

Landis counters that the motion of stars is slow, at least compared to the lifetimes of civilisations in human history, although Wright points out that all a colony then has to do is wait for one of its neighbours to die off before moving in. Landis is unperturbed by the critics, however.

“A lot of people have commented saying they don’t think it is a sophisticated enough model and that they think it needs more work, and that’s fair,” he told me during an interview in 2013. “I just worry that a model that has too much sophistication into which you are putting data that has no validation is hard to really justify.”

Perhaps percolation theory as it stands isn’t therefore the best solution, but instead maybe it’s a good starting point for considering alternatives to how civilisations could migrate through a galaxy.

2. Their energy requirements are low

Another alternative may be that they never really begin to climb the Kardashev ladder at all, which could lead to two outcomes.

Serbian astrophysicist Milan Ćircović has described civilisations that are driven by optimisation, rather than expansion. The optimisation is focused primarily on computation (Jason Wright suspects that Type II and Type III civilisations would use large amounts of their energy for computing, which produces heat). An optimised society would not need to colonise other stars and capture their energy because they would lack the population or computing power that would otherwise soak up vast amounts of energy.

“An optimised society is intrinsically less likely to be observed because most of the things that we tend to associate with advanced technology and advanced societies actually consist of waste energy and the waste of resources,” Ćircović, referring to the Kardashev scale, told me in an interview around five years ago.

An optimised society need not be limited to one planetary system – they may still wish to explore, sending out probes to all corners of their galaxy, but colonising star systems to harvest their energy and resources is not on their list of ‘to do’ things. Rather than building galactic empires, optimised civilisations could be like the ancient Greek city states, which would send out scouts just to explore, says Ćircović.

Jason Wright acknowledges that a galaxy-spanning civilisation need not be a Type III civilisation; it could still be possible to colonise a galaxy without having to build Dyson spheres around every star. Such galaxy-spanning civilisations could be very hard to detect. However, if an advanced civilisation has had time to colonise a galaxy, why would they not build all those Dyson spheres? The distances involved would mean that colonies, or clusters of close colonies, would develop their own societies relatively independently of the others. Some may chose to become optimised, others may be expansionist and energy-hungry, but the result would be a galaxy-spanning civilisation that does not use all the energy of that galaxy.

3. Black holes are more interesting

I confess, I’m rather taken with this idea. It could still be wrong, but it strikes me as being more purposeful than percolating slowly and somewhat randomly through a galaxy, and more ambitious than an optimised city state.

Suppose Kardashev is right, and Milan Ćircović is wrong, and that civilisations actively seek energy. So let’s imagine that a civilisation reaches Type II status, after which it heads for the stars, perhaps even building Dyson spheres around some of them. Estimates suggest that there could be as many as 100 million stellar mass black holes in our Galaxy. Some of them remain dark, while a few are lit up in X-ray binary systems, feeding off a companion star. Sooner or later a star-faring civilisation is going to bump into a black hole. What then?

black_hole2

Image: Simulated view of a black hole in front of the Large Magellanic Cloud. The ratio between the black hole Schwarzschild radius and the observer distance to it is 1:9. Of note is the gravitational lensing effect known as an Einstein ring, which produces a set of two fairly bright and large but highly distorted images of the Cloud as compared to its actual angular size. Credit: Alain r (Own work) [CC BY-SA 2.5], via Wikimedia Commons.

Black holes seem to hold a special fascination for physicists: they create the most extreme gravitational conditions in the Universe, making them a great place for thought experiments. Numerous physicists including John Wheeler, Roger Penrose, George Unruh and Princeton’s Adam Brown have all speculated on methods by which, in principle, it might be possible to draw energy from a black hole. And my, so much energy! Paul Davies in his book The Eerie Silence suggests that a spinning black hole could power our present human levels of energy consumption for at least a trillion trillion years, long after the stars have gone out.

There are numerous options for deriving energy from black holes. Hawking radiation is not the best option, because it leaks out at a trickle, is very low temperature and is difficult to bottle. Small black holes that evaporate relatively quickly would be more efficient for this, but they would not last long. Hawking radiation would make the perfect waste disposal system though – drop your rubbish into the black hole, wait a little while and get energy from Hawking radiation back out.

Then there is the energy radiated by the hot plasma in an accretion disc around a black hole, which is often funneled away in a magnetically collimated jet. This could be created artificially – perhaps by sending a steady stream of asteroids and comets, perhaps even planets and stars themselves using Shkadov thrusters (giant mirrors larger than a star, which act as immense solar sails, the mirror’s huge gravity pulling the star along with it) to nudge the star towards the black hole. Alternatively, there are instances in nature whereby a star naturally exists next to a black hole – the aforementioned X-ray binaries (though in many X-ray binaries the black hole is substituted for a neutron star). Jason Wright suggests that the energy efficiency of such a system would be 10 percent, making it the most efficient sustainable method of converting mass to energy.

Then there is the rotational energy of a spinning black hole. To illustrate the concept, in their book Gravitation, Charles Misner, Kip Thorne and John Wheeler imagined some form of cosmic dump truck swooping down through a black hole’s ergosphere – a region just outside a rotating black hole where an observer is forced to rotate with the black hole, but at the same time can also extract energy from the black hole. The dump trucks, each packing a million tonnes of rubbish, take a particular trajectory through the ergosphere and are able to tip out their industrial waste into the black hole. The dump trucks recoil from the ejection of the rubbish and are catapulted back the way they came, stealing away some of the black hole’s rotational energy in the process. Because the mass of the black hole has increased by the mass of the garbage dumped into it, the mass-energy of the black hole is higher than before the dump truck entered it, allowing the truck to leave with more energy than it started with. To put this in terms of the amount of energy available, up to 29 percent of the mass of the black hole is expressed in terms of its rotational energy, according to Paul Davies – this is leagues above the one percent of a star’s mass that is radiated away over a stellar lifetime.

accretion_disk2

Image: Artist”s impression of a black hole and a normal star separated by a few million kilometres. That’s less than 10 percent of the distance between Mercury and our Sun. Because the two objects are so close to each other, a stream of matter spills from the normal star toward the black hole and forms a disc of hot gas around it. As matter collides in this so-called accretion disc, it heats up to millions of degrees. Near the black hole, intense magnetic fields in the disc accelerate some of this hot gas into tight jets that flow in opposite directions away from the black hole. Credit: ESO/L. Calçada.

The difference between collecting energy from stars and latching onto black holes is that you can do more with black holes than simply generating power, and it is these extra factors that could make them more attractive than colonising the stars. For one, black holes could potentially make the most powerful computers in the Universe. A computer’s computational power is a function of both its computational efficiency and its mass. Black holes have great mass, but computational efficiency? That would take a bit of organising. The trick is to use Hawking radiation, which is formed of pairs of virtual particles that appear close to the black hole’s event horizon.

For each pair, one particle heads inwards towards the black hole’s singularity, while the other quantum tunnels its way through the event horizon and escapes. However, both particles are forever connected via quantum entanglement. Now, send matter into the black hole – perhaps the waste on the dump trucks – in a specific fashion to ‘program’ the black hole, and it will interact with the infalling Hawking radiation particles. This interaction, specifically fine tuned, will then change the state of the outgoing Hawking radiation particle via entanglement, hence producing an ‘output’. Of course, all the Hawking radiation would have to be gathered, sorted through for the relevant bits of data and processed using knowledge of quantum gravity, a theory that remains stubbornly beyond our limits for the time being.

Then there is the possibility proposed by Sir Roger Penrose that black holes are the birth-sites of new universes; an advanced civilisation may choose to somehow enter one of these universes in a black hole, therefore disappearing from our Universe.

Pressing black holes into service could possibly be within reach of an advanced civilisation; black holes provide astoundingly attractive destinations for intelligence. Clément Vidal, in his book The Beginning and the End, points out that there is a surprising over-abundance of X-ray binaries within three or four light years of the galactic centre – maybe advanced civilisations around their stellar-mass black holes migrating towards the supermassive black hole at the centre of our Milky Way galaxy?

Perhaps. The stars still have their attraction, but as the G-HAT result shows, we need to start looking for alternatives to Type III civilisations. These are just three ideas – your own ideas may well be better!

tzf_img_post

Comments on this entry are closed.

  • Peter May 8, 2015, 10:18

    Type 3 should be so advanced, they would like gods to us. Why should they waste energy in form of infrared radiation?
    -I doubt there would be the problem of hot dyson spheres for them, most likely they wouldn’t have a need for dyson spheres, because they have other means of generating energy. Neanderthals didn’t know anything about nuclear energy, we most likely have no idea about the means of type 3 energy generation.

  • John May 8, 2015, 11:45

    I was lucky enough to get a Q and A session with professor Wright a couple of weeks ago (here: http://ancientsolarsystem.blogspot.co.uk/2015/05/q-and-with-professor-wright-of-g-hat.html) and one of the things he mentioned was that there are objects that look like obscured active galactic nuclei. The main reason he wasn’t as interested in these as a first target for a search was that it would be hardser to distinguish an natural obscured-by-dust central black hole from one that was being obscured as ameans to collect energy from it. He also mentions a number of strange objects G-HAT has discovered which I personally wonder if modification by an ETI might be on the list of possible explanations.

  • Eric Wargo May 8, 2015, 12:09

    Really fascinating article–so much food for thought here.

    As an anthropologist (former), I come at the problem of “where are the Type III civilizations?” a bit differently: I think it is worthwhile considering that a lot of the problem may be in the assumptions latent in the concept of “civilization”; civilization as we understand it (i.e., ever-expanding communities of people, having families, etc.) may not at all reflect the future trajectory of a technological species beyond a certain point in its development (e.g., the “Singularity,” however you want to define that). As beings become effectively or literally immortal through technological advancement, it could put an end to the family as well as colonization/exploration “in the flesh” in search of Lebensraum; with the ability to ‘inhabit’ the universe virtually via drone science platforms serving as extensions of themselves (the distributed self), our descendents (and by extension the descendents of other technological civilizations) could become immortal, insular, stay-at-home types (I develop this theory here: http://thenightshirt.com/?p=1456). Energy requirements as a resource for computing, though, is another matter, I suppose. Your black hole model is very, very interesting.

  • Dmitri May 8, 2015, 12:49

    I can’t help myself than shout “Hold your horses!”. The question is not in quantity of galaxy explored rather than the l.y. distance the explored galaxies lie. Recent data per Statistical Drake Equation by Claudio Maccone show with 75% probability the closest civilization lies within 1361-3979 l.y. distance. There are no intelligent civilization within 500 l.y. region from Earth. Per SDE in Milkyway alone there should be 4590 civilizations but it does not answer in which class on Kardasahev scale. If calculated SDE civilizations would be equally distributed then each civilization would be 30 000 l.y. apart.

    http://phys.org/news/2012-12-alien-civilizations.html

    What I’m most intrigued by the survey is the information what distance in light years it covered. As far I searched I didn’t see any on that. AFAIK we lack capability to detect civilizations beyond 500 l.y. and not detecting hopeful IR signal in galaxies studied does not make things more conclusive.

  • Mark Zambelli May 8, 2015, 13:24

    Nice to see you here Keith (Astrofest, Cardif Astro. Soc. and here, cool).
    The first I heard of the concept that ETIs might find black holes enticing was from Paul Davies, as you mentioned above, although I think he was referring to artifacts rather than waste heat. Exciting avenue nonetheless.

    I have a question about any sample of elliptical galaxies. Yes the signal/noise ratio will be better due to their low gas/dust environments but does the fact that they are low in gas and dust impede the prospects of finding life in these types? If their metal content is as high as a typical spiral then I guess not and we should indeed expect just as much chance for life to arise. If the precursors to modern, local ellipticals experienced starbursts (or, if the elliptical is the result of spiral-mergers) then the environment billions of years ago should’ve favoured complex chemistry on planetary surfaces that will’ve needed the several billion year evolution that we had that eventually throws up a K2.n civ. So gas/dust poor ellipticals today could be harbouring complex life/advanced civs afterall. Any thoughts anyone?

    Also, the more we see our own technology becoming optimised in our efforts to curb waste energy, the more I find it highly likely that an advanced ETI society would know how to really do it (maybe it’s even a ‘great-filter’). It’s been making me frown a lot lately when considering the SETI implications… but the future remains rosy (with more than a hint of Infra-Red) and I’m looking forward to future searches.

  • Alex Tolley May 8, 2015, 13:34

    I think the Black Hole concept falls into the same assumption trap as the KII/KIII of assuming the need for massive energy.

    On Earth civilization is currently dominated by teh need for growth. This is in part due to our model of required returns needing growth, and part our ability to expand. As we have discussed before, this growth cannot continue on Earth for many centuries. Even if we become a KII there isn’t a lot of time before growth would have to stop. Galactic expansion is even worse. For example, assuming 100bn stars to use round numbers, KII-KIII at just 1% growth is finished in ~2500 years, a mere blink in cosmic time. Another 2500 years and you would fill the universe. Because of light speed constraints, growth would de facto have to be much less than 1%. Effectively static after KII status. Therefore we cannot have our model of economic growth after KII.

    To me this means that once KII is achieved, economic stasis is the result. This doesn’t preclude incremental expansion, but it would preclude our current Terrestrial approach. I don’t quite know what that means in terms of our type of civilization or any other that would use a similar economic model. Perhaps this restricts the technological level of civs and their likely expansion.

    It seems to me therefore that advanced civs must transcend in some way, and quite possibly well before they even reach KII, as that is almost a hard stop for material expansion, whether they use stars or black holes for energy.

  • Harold May 8, 2015, 13:47

    Thank you for the article.

    I think Kardashev’s assumptions about the energy consumption of TIs is analogous to the assumptions made about human population growth decades ago. The mechanics governing human population growth are more complex than could be predicted and instead of the predicted run-away growth, population levels are plateauing. Even if we assume the consumption mentality of a Type II civilization (perhaps civilizations of clones of Donald Trump), it may be impossible for it to become a Type III civilization. Could every star support Type II colonization? The system would need enough material to build collectors, habitats, the technology using the energy, and the material to sustain an ecosystem whether it be biological or virtual.

  • tchernik May 8, 2015, 13:55

    If we can’t see any signature of a classical Kardashev type III civilization in such a big sample of galaxies, it logically follows they simply don’t exist in the observable universe, with a very high degree of confidence.

    One can think that the observable universe is a small fraction of what there is. We are simply seeing the state of this sample of galaxies as they were at the time their light started coming towards us. This means that nearby galaxies are seen as they were relatively recently (a couple million years ago for M31, for example) and it goes back further in time as we see farther and farther galaxies.

    It is also good to notice that, even taking this into account, these times are not really that long in terms of astronomic times, as stars and galaxies live for much longer than that, and even the Earth itself has a history going for billions of years as a living planet. This means that even taking into account the age of the light of the galaxies we are seeing, we should expect for some Type III civilizations to emerge in the sample, if they existed.

    But they apparently don’t. Therefore there are not many options left: either type III civilizations don’t exist or they develop in very different ways to those we currently foresee.

    This option of them staying close to big energy sources (and possible massive computers) looks as a very promising candidate for explaining the lack of visible Type III civilizations. Civilizations may simply expand a little until ensuring their own energy and computation safety, and then they remain in just a few star systems with the right conditions for giving them just that.

    I think there are other potential concomitant explanations, mostly because our own civilizations is trending to become more efficient in energy consumption as technology improves rather than profligate, even if we are still growing materially and energetically now.

    It is very possible we find out that really advanced civilizations are very low power consumers, especially once the need or drive to grow ceases to be there (that is, we could reach a point where things are “good enough” in technology and living conditions, and the drive to search for more space and energy simply ceases).

    Basically, the drive for expansion may be a temporary phase in the life of a civilization, one that unavoidably ends way before any civilization consumes the galaxy they live in.

  • Harold May 8, 2015, 14:31

    If I were the entirety of a young intelligent civilization, I would be terrified of a Type 2.x or 3 civilization. The existence of a Type 2.x or 3 would preclude a galaxy partially filled will other complex life forms, some of them intelligent but perhaps not technical or star-faring. Could a type 2.x or 3 civilization afford to preserve the biodiversity of a galaxy?

    Or could the existence of life be another impediment to a civilization reaching Type III? With humanity, the consumption of information is beginning to keep pace with the consumption of energy. Perhaps a solar system that supports life is more valuable as an information resource than as a material resource.

  • Michael May 8, 2015, 14:41

    A possible reason why type iii civilisations don’t exist or find it difficult to approach in energy consumption is in-fighting or stagnation caused by even small changes or mutations. If you look at our ‘intelligent’ species there are footnotes in history in which ‘sections’ of a supposedly common ancestral race view themselves as superior to another.

    As an example say we had a space faring species that starts off in Star ships in all directions, there is bound to be changes in each, changes that when they are brought back together just don’t like each other or have different views.

    Small scale changes can have huge implications even on the atomic DNA level, in essence a genetic butterfly effect.

  • Lord May 8, 2015, 15:22

    Civilization moves away from 18th century technology towards new forms of energy, like dark energy.

  • Larry Kennedy May 8, 2015, 15:56

    I agree with the possibility of the various efficiency arguments. Many would be bothered by the extreme convergence implied. To me the black hole idea requires a far less likely convergence.
    It seems to me that percolation is just a less likely subset of Sagan’s near universal self extermination.

  • Black Sci-Fi May 8, 2015, 16:03

    Nice thought experiment article. Great comments. The scales of distance and power reduce the desire for ever reaching the levels of energy generation and consumption necessary to accomplish the ends denoted by meta-consumption. Ergo: “The Ends don’t justify the Means”….if you have the tools available to meet those ends.

    We here on earth are already reaching the point wherein, via Musk, Inc, we are rethinking our generation and consumption of power and reducing it to a personal need generation (battery driven homes/electric cars) rather than a large scale generation for civic/military purposes. ATC, the civic/military needs seem to always lead the way to inovation. And, based on the criteria for reaching Type 2 status (ie: don’t blow yourselves up as you attain new levels of power generation) it is illogical to think that population control and the economics therein wouldn’t have reached a similar level of enlightenment.

    Solar and other eco-energy generation will become more useful and less wasteful in the future. This trend will only continue into infinity. Personal transportation will require only the power an individual can generate by using more and more efficient means. Individual homes may give way to a more hive type multi-unit dwellings for more efficient generation and consumption of power. Keep in mind that all these things can be done without even evolving (?) into a Type 1.5 society. Add to that the efficiency of personal power generation and you arrive at a planet that generates power on an individual use basis and not for standby consumption and waste.

    While the idea of immortality seems to be behind all of these ideas, who will be worth saving if we put all our resources into leaving the planet? Certainly not those who propose destroying Earth to…uh…save humanity.

  • DCM May 8, 2015, 18:45

    It would be interesting to find evidence of such a civilization but what do you intend to do if you find one? We wouldn’t be able to engage in any quick exchange of information with them and I don’t think we should try.
    Our main goal should be to occupy our solar system and any nearby so, as I may have mentioned before, we need to start building and improving biosphere habitats in space and methodically making use of the planets we can. The way to do that is to create wealthy organizations and persuade governments to help in the enterprise.
    That doesn’t mean to stop looking, but that’s a minor priority since we don’t know anything of the nature of any civilizations or equivalent lifeways.

  • Al Jackson May 8, 2015, 21:34

    A spinning ~solar mass black hole rotating at the maximum can be used to extract 10^53 ergs/sec using the Blandford-­Znajek process. The whole galaxy produces 10^44 erg/sec in electromagnetic radiation. A civilization living near a spinning black hole already has about 10^9 galaxies to use! That’s Type IV!

    https://en.wikipedia.org/wiki/Blandford%E2%80%93Znajek_process

  • Brian May 8, 2015, 22:04

    First off I want to say in my opinion this has been the most interesting to happen in SETI in a long time. To me the results make sense, on Earth we have seen that with an increase in wealth and education population growth tends to stabilize or decline so why would an advanced civilization need to expand to dominate the entire galaxy? I mean I can see a few stars but why the whole galaxy, is there some kind of alien manifest destiny? it always seemed like an arbitrary limit to me especially since a 2+ could survive any conceivable natural disaster. Sagan proposed scaling a civilization on how much information it accumulated rather than power consumption which makes sense to me, after all Iraq uses power electricity than Ireland but which would you rather live in? can a similar study be done in our galaxy to see if type ii civilizations exist?

    Someone had posted something similar about black holes within the last month. I find the idea of a civilization living inside a black hole interesting. I have to ask though as a laymen who has only a popular understanding of black holes, isn’t something that passes the event horizon of a black hole causally cut off from the rest Universe? I mean its fascinating but how could we ever test that? would a black hole with a civilization inside of it emit hawking radiation differently or something? I ask because while its interesting speculation if there is no way to ever test it then its sort of a dead end.

  • llanitedave May 8, 2015, 23:11

    A typeIII civilization would imply that all of its inhabitants have a single shared culture and technology, that allows them to build Dyson spheres and move about seamlessly between the polar and equatorial regions of the star system. That movement, even without the associated manufacturing and industrial transport, requires huge amounts of concerted energy and cooperation.

    The obstacle here is that, unless you assume that warp drive is an option, even a very advanced civilization is subject to speed limits. Communication between distant parts of a system would be slow, and physical transportation would be slower still. There is plenty of time and opportunity for divisive forces to dominate in such a situation, creating political chaos that works against the formation of a single monolithic civilization surrounding a star.

    An insight that’s been valuable to me is the realization that most of the accessible material resources of a star system are found not in its rocky planets, if they even exist, but in the small icy bodies distantly orbiting — the Oort Cloud and Kuiper belt equivalents. If a civilization expands from a home planet to live near and mine these bodies, then there’s likely to be some extreme cultural diversification as different populations develop different individual histories and traditions that adapt them to the particular region and group of bodies they are exploiting. The energy requirements for such a lifestyle are low, the diversity is high, and it seems to me a real obstacle to the evolution of focused cooperation among the denizens of a single star system, much less those of a stellar neighborhood or an entire galaxy.

    A single species may be the first to leave its home planet, and its descendents may indeed colonize the galaxy, but in doing so it is no longer a single species or single culture — particularly since cultural evolution and biotechnology can proceed in their own directions even faster than can biological evolution. These changes are very unlikely to be coordinated across populations.

  • Kolja May 8, 2015, 23:40

    I think that if it doesn’t destroy itself first any civ between type1 and type2 should be able to attain a stable state which could sustain it within its solar system indefinitely (as long as its star is alive). Also, that same civ should be able to reach a technological level which allows it to colonize the nearby stars at about the same time. It follows that as long as the civ is capable of colonizing the nearby stars, the civilization, now occupying multiple stars, doesn’t need to limit it’s growth (at least at the edges).

    If that’s true, one could indeed speculate that the curiosity is the only force that could drive a civ to became the type2 civ. While it can limit its growth and consumption of energy by entering the “stable state” it can’t limit its imagination and curiosity. For satisfying that need the civ needs calculating power and energy to do the calculations, so Dyson sphere would be constructed eventually.

    But there’s a limit in energy output of a star or even of the black hole. So, because any goal that a type2 civ could undertake is requiring energy for the calculations, the goal itself could only be as large as the energy output of a local star. And stars (or black holes) come in finite sizes. That fact limits the scope of the calculation goal.

    Therefore, once you build the largest mega-giga-tera… Large Hadron Collider around the largest black hole in the galaxy, what then? You do not need to construct a Dyson sphere around each and every star you colonize because you don’t need to repeat the old experiments all over again, and it would be impossible to replicate the energy output of the most unique and energetic objects in the galaxy anyway. Moreover, you need more time to construct the Dyson sphere around the star you colonized for doing your own calculations then to receive the results from somewhere else, where the calculation you require was already done.

    You don’t have plans for constructing the same LHC elsewhere on Earth as it would be wasteful. You only have the drive to construct another LHC if it’s a magnitude or two more capable compared to the existing one, and once you hit some absolute limit (a Dyson sphere energy output) you’re done.

    And you are done even before that if there’s a real limit to the knowledge you can attain. Who knows, when the Grand unifying theory is postulated and confirmed, maybe there will be nothing else to pursue scientifically. And I doubt you need a Dyson sphere to power the food production and pleasure seeking of a civilization that stopped being curious cause there’s nothing to be curious about.

    So, If I’m just half right, maybe there’s no real need for type3 civ at all.

  • Moran May 9, 2015, 1:23

    Great article. Black holes have always interested me, as it seems that a civilisation that mastered them would have an advantage in energy production if small Kerr-Newman black holes were used to convert mass to energy. It might turn out that the only energy source powerful enough to enable a truly interstellar civilisation is a artificial black hole.

    On the subject of a TypeIII civilisation I have always wondered why they would bother? Even for such a civilisation, esp. a young one, a Dyson sphere would be a crowning achievement of their culture – comparable perhaps to the building of the pyramids by the Egyptians, or the Great Wall by the Chinese. But what could motivate them? Transcendence aside I find it hard to imagine any reason that a society or culture could gain the impetus to achieve such a feat. The pyramids were, after all, built somewhat unwillingly at the command of a god-king.

    Just my two cents worth, and time will tell…pity we won’t be around to see it.

  • Ed May 9, 2015, 7:21

    Could it be that our expectations of what a Type 3 civilization would look like are wrong? What if a lot of what we think of as energy going to waste is really taking part in some advanced form of computation, so efficiently encoded as to appear like noise?

    How do we know that a lot of what we see as natural has not been influenced by life far in the past? What if the Milky Way is a Type 3 civilization, that looks natural to us, but is full of, say, entangled quantum states correlated in very sophisticated, subtle ways, thinking about…something…that is so far beyond us as to appear meaningless. Could it be that they’re more interested in dust clouds and stars than planets and asteroids?

    What if we’re beneath their notice (and would still be even if we build a Dyson sphere and colonize a few thousand stars)?

    What would a Type 3 civilization think about? What would its goals be? What if these would appear to be indistinguishable from nature to us?

  • Mark Zambelli May 9, 2015, 7:25

    @Alex Tolley

    “To me this means that once KII is achieved, economic stasis is the result. This doesn’t preclude incremental expansion, but it would preclude our current Terrestrial approach. I don’t quite know what that means in terms of our type of civilization or any other that would use a similar economic model. Perhaps this restricts the technological level of civs and their likely expansion.

    It seems to me therefore that advanced civs must transcend in some way, and quite possibly well before they even reach KII…”

    I couldn’t agree more. The more I think about our current civilization and where it will soon be, the more I’m convinced that what we have in store for us over just the next century or so will be so changing that we either go extinct or we become what is referred to as ‘trans-human’. As Nick Bostrom has explored ( http://www.nickbostrom.com/ ), the current human condition is unique and always tempory as we strive to change our lot and provided we minimize the associated existential risks so as not to become extinct then what we might become will be as good as alien to our current view.

    If we are destined for any form of singularity that is (probably) on our horizon then how things unfold afterward is up for grabs. Although I am hopelessly unsure as to what we may come-up with as replacements, I can imagine a future for us that doesn’t have an economy as we would recognize it or indeed even a familiar notion of society as we would understand it. What we will then do I have no idea.

    With these musings I also am starting to doubt whether the logical and succinct scale that Kardashev came up with has any basis in reality. Maybe there are countless reasons why a KII civ doesn’t progress to a KIII and we’ve already explored a few (optimised civs and the requisite for low power consumption may be all one needs). With the vast amount of change in thoughts on this matter since Kardashev’s 1960’s worldview, maybe the Kardashev Scale isn’t the logical framework for any civs development, although it should still be useful as a guide for our searches… searches that we would be remiss in not conducting BTW.

  • Mark Zambelli May 9, 2015, 7:45

    @Al Jackson

    Thanks for the link to the Blandford-Znajek process. That process sounds so good that maybe a near-KII civ with a handful of local colonies could aquire that knowhow and leapfrog to KIV overnight!… all without needing to build even a single Dyson Sphere and all the while leaving their galaxy pretty much untouched. Fascinating.

  • Tom Mazanec May 9, 2015, 9:04

    For a collaborative, hard science fiction depiction of a Kardashev-Sagan 2.8 Earth derived civilization in the year 12,569 AD, see the Orion’s Arm Universe Project http://www.orionsarm.com

  • Harry R Ray May 9, 2015, 9:55

    Three thoughts on this: FIRST THOUGHT: “1. They fail to colonise all the stars.” The BEST was to colonise the entire galaxy* in 10 million years does not even INVOLVE near light-speed travel. Just inhabit ALL of a star’s oort cloud objects, and CROSS OVER when ANOTHER star passes very close by ( and, as a result, the two Oort clouds pass through each other; then, REPEAT ad infinitum. After a very SLOW start, the colonisation proceeds GEOMETRICALLY! BUT: 15% of stars nay NOT have Oort cloud analogs, so; having colonised 85% would they EVEN BOTHER to colonise the remaining 15%? THOUGHT NUMBER TWO: If Dmitri is right, there will be NO TIME where ANY galaxy is “ASIMOVIAN” (i.e. where ONLY ONE INTELLIGENT CIVILIZATION HAS AN ENTIRE GALAXY TO THEMSELVES). Could MULTIPLE ET’s EVER CO-OPERATE WELL ENOUGH to colonise every star? My guess is: BIOLOGICAL et’s;NO, MECHANICAL et’s;MAYBE. THOUGHT NUMBER THREE: I assume the black holes mentioned in the post are stellar mass black holes. WHY NOT SUPERMASSIVE BLACK HOLES? A KIII civilization may not be up to the task of taming such a beast. It may take a KIV civilization to do THAT!

  • Michael May 9, 2015, 9:59

    Black holes would make great communication points as they have gravitational focus points that are quite close and would have a low noise emission provided they were not feeding.

  • Alex Tolley May 9, 2015, 12:10

    @llanitedave
    A typeIII civilization would imply that all of its inhabitants have a single shared culture and technology

    Even on Earth our western civilization isn’t homogenous in terms of culture and technology. It has been the same looking at all the imperial civilizations in history. I see no reason why a KIII couldn’t be a multi-species civ with widely varying cultures and technology as long as there was some cohesiveness between them in different stellar systems. This might be an issue of definition, and it is quite possible that any particular civ is represented by a small part of teh total, but that doesn’t mean that in aggregate they could fill the galaxy and harness all its energy if desired.

  • Alex Tolley May 9, 2015, 12:18

    @Al Jackson

    10^53 ergs/sec using the Blandford-­Znajek process. The whole galaxy produces 10^44 erg/sec in electromagnetic radiation.

    Given conservation of energy, that would imply that fusion energy radiation emissions are just a billionth of the energy in matter. I find that hard to believe, as that would imply that almost all of the energy is in the ejected matter. Yet matter-anti-matter annihilation isn’t a billion fold better than fusion AFAIK. It it was, we could build star ships quite easily once we could manage the technology. We might even be able to propel those black holes around quite easily!

  • Agb May 9, 2015, 16:11

    I have always had a hard time buying off on Dyson Spheres as a realistic means of energy collection. Would the raw materials of creating such a sphere outweigh all of the raw materials found in a typical system? If we reached Kardashev levels enabling us to do so, it would take far more raw material than we have in our Sol system, for example, for us to build a true DS around Sol. Even a Dyson Ring (a solar energy cell in the form of a belt) would consume planetary resources.

    I feel it’s time to rethink all models, especially those created in the mid 20th century. Our plain observations of space today alone call for it.

  • Michael May 9, 2015, 17:24

    @Al Jackson May 8, 2015 at 21:34

    ‘A spinning ~solar mass black hole rotating at the maximum can be used to extract 10^53 ergs/sec using the Blandford-­Znajek process.’

    Since slowing down the black hole involves energy loss you would need to specify a total energy as eventually the black hole stops spinning. But the power generated over short time spans could easily out shine a galaxy or many thousands.

    SDSS J0100+2802 (SDSS J010013.02+280225.8) is a hyper-luminous quasar. It unleashes an immense amount of power equivalent to ~40,000 times the luminous of all of the 400 billion stars of the Milky Way galaxy combined.

    Just thinking if material send around one side and some the other side of the black to collide would be helpful in generating more energy or generate a powerful radiation beam as the energy is focused by the powerful gravitational lensing effect. As for communication and information storage entangled electrons could also be used, not sure if they could be used to probe the interior of the black hole as what happens to one happens to the other.

  • Adam May 9, 2015, 19:00

    Here’s a thought. The Eddington limit means an accreting body produces a specific power generation level of ~6.4 W/kg. The Sun averages 0.0002 W/kg. Therefore collapsed objects are ~33,000 times more compact power sources than the stars, thus that much more attractive to power-intensive Civilizations. Red dwarfs are even more miserly – the lowest mass Main Sequence star puts out 1/8,000 the Sun’s luminosity from ~0.075 Solar masses. That’s a miserable 4E-7 W/kg.

    SO are the Super-Civilizations choosing to Live Fast?

  • Adam May 9, 2015, 20:07

    OTOH the tireless efforts of Claudio Maccone drawing attention to the *huge* band-width that gravitational lensing enables, tells us that the whole Galaxy can be networked, in High Definition, for very low power requirements. A Galaxy-spanning Civilization, ultra-long-lived, doesn’t have to shroud the stars in solar-collectors and computronium Jupiter-Brains.

  • Larry Kennedy May 9, 2015, 20:39

    @ Agb
    A sphere at the radius of the Earth is in the neighborhood of 300 thousand trillion sq. kilometers . Give 100,000 kilograms per sq. kilometer of orbital solar collector and another factor of ten to provide a good overlap. That works out to about the mass of Mercury. These are very conservative numbers and of course it is very unlikely that most would be at one AU.

  • Larry Kennedy May 9, 2015, 20:50

    Many people have pointed out the certain huge divergence in an out spreading wave from one solar system. We have traditionally applied the term civilization for this. Obviously without ultra FTL the term civilization doesn’t apply well. It also creates confusion in these matters because things that are virtual truisms in the usual meaning of civilization, like universal limited lifetime, have little application here.
    The problem of course is what other convenient term could we use. I don’t at all follow why any coherent civilization would be necessary to spread throughout the galaxy. People managed to spread throughout the Earth without it. Indeed the opposite was often more operational.

  • Mark Zambelli May 10, 2015, 7:20

    @Agb

    Also, I would like to point out, the concept of a ‘solid’ shell is not true to Dyson’s original idea but has been born from Sci Fi. Dyson proposed an innumerable swarm of orbiters acting as collectors arranged spherically. The solid shell spheres have so many more problems than just mass requirements, as discussed on this site previously.

    The true Dyson Sphere then is a lot more managable and will grow incrementally with the potential for a stacked Matrioshka-like arrangement in the extreme.

  • Jer May 10, 2015, 11:41

    Interesting, but I have to side with a Civilization value system (approx. #2) veering away from Ray-Bradbury-esque type families, growth, colonization, and community-building to a more ‘immortal, retired seniors/tourists in small to medium groupings with near-limitless range RVs’ system, touring outward and onward each in an optimized, self-contained living environment, perhaps occasionally meeting up with others – maybe at a technological tail-gater in the vicinity of a Black Hole. We may detect these agglomerations, however. But the essence of my thinking is rare and small population groupings only, widely distributed, with small increases in population only, perhaps augmented by probes or small outposts/labs. The key question is what the energy/supply demands would be for a craft containing a small grouping of long-lived/near-immortal human beings to live full and rich lives with as minimal physical contact with others and hostile space body surfaces. Is there any reason that such a ship could not be created with near-infinite resource recycling? ..and how far would such a widely spread ‘civilization’ go if each small grouping insisting on being isolated within a large portion of a l.y. away from each other based on an increasing population/ship size at a few % per year/decade/century (at least maintaining ‘civilization’ population size)?

  • Al Jackson May 10, 2015, 12:39

    @Alex Tolley
    It’s amazing there is that much energy in the space time that swirls about a black hole’s ‘event horizon’ that is moving with a speed almost the speed of light.
    That is a ‘max’ spinner.
    What was discovered is that ~30% of the rotational energy in the ‘dragged’ spacetime around a Kerr Black Hole is available to be extracted. For a 10 solar mass black hole this is 10^55 ergs.*
    I should say that I don’t expect all that energy to be extracted in one second!
    One can see that only a tiny fraction of that is extracted is an enormous about of power.

    *Introduction to Black Hole Physics
    By Valeri P. Frolov, Andrei Zelnikov
    page 291.

    See also Black Holes and Time Warps: Einstein’s Outrageous Legacy
    By Kip S. Thorne

  • Michael May 10, 2015, 15:11

    Here is an interesting simulated merger of blacks holes.

    http://www.nature.com/news/black-hole-mergers-cast-kaleidoscope-of-shadows-1.16283

    I am perplexed as to why advanced aliens would need so much energy in the first place. But having said that if a techalien race had access to a black hole nearby they would control an incredible volume of space. Not only would they be able to see incredible details at great distances with the gravitational lensing effect in all directions they could also concentrate a huge amount of energy in any direction in a small volume of space, a truly ultimate weapon.

    Note to Dept. of defence…We need one.

  • Ron S May 10, 2015, 15:19

    Al: “What was discovered is that ~30% of the rotational energy in the ‘dragged’ spacetime around a Kerr Black Hole is available to be extracted.”

    That’s the maximum percentage of the BH’s total energy that can be in its angular momentum. It can be much less, though I don’t offhand know what is theoretically estimated for a typical collapsing star.

  • Alex Tolley May 10, 2015, 17:35

    @Al Jackson
    I should say that I don’t expect all that energy to be extracted in one second!

    My mistake. I was thinking that the figures referred to total energy released in the BH and the galaxy over their lifetimes. Now I understand what you mean.

    Alternatively, if the civ knew when a supernova was to detonate (or create a supernova), they could collect the energy using a Dyson sphere/swarm around the star. Assuming that was so, it might be worth counting IR pulses in time as a remnant of these harvested supernovae and seeing whether their rate increased in time as civs appeared (or even if such “IR transients” even exist at all).

    We tend to think of energy harvesting as long term stable systems, but storage of a short term energy event might be an alternative. For example there was the idea of collecting the heat of nuclear bomb detonations in rock for artificial geothermal power. Today the focus is shifting towards battery storage for variable renewable energy. So rather than think in terms of long term stellar energy harvesting, just capture a very energetic event and then subsequently dole out the stored energy. This offers another avenue to observe the universe for ETs.

  • Daniel de França May 10, 2015, 19:29

    Maybe warp drive exists and it is done pretty much “straight forwardly”. But to save energy, just small probes visit other planets, and send information back where in a kind of virtual reality, people explore the planet without having to actually going there disturbing it. So, it’s also a type of galaxy zoo.

  • Eniac May 11, 2015, 0:56

    The idea of a energy-frugal transcended galactic population is interesting, until you realize that a “frugal per person” population will still require unlimited amounts of material and energy as the population grows. If we assume the individuals to be “transcended” in the sense that their minds run like computer programs on commodity hardware, there can really only be three things limiting population expansion: 1) material resources required to build and maintain the hardware, 2) power required to maintain computation on the hardware, or 3) a conscious and perfectly dictatorial (or perfect consensus) decision that any production or reproduction of new individuals never exceeds the replacement rate. Such replacement rate would probably be quite low, as long as everyone remembers to make their regular, remotely sited backups.

    Point number 3) is rendered unlikely by a number of considerations, prominent amongst them the ease with which transcended individuals could replicate themselves and, for example, send copies of themselves on explorative journeys while simultaneously staying safely at home. Another strike against point 3) is that the perfect dictatorial enforcement (or perfect consensus) would tend to break down due to communication delays as the population spreads far enough.

  • Keith Cooper May 11, 2015, 7:34

    Thanks to everyone for their comments and ideas on the subject. It has also occurred to me since writing the article that building Dyson spheres probably isn’t going to involve heavy labour. They’ll be built by robots, maybe self-replicating machines that will be sent out into the cosmos to prepare star systems for colonisation. Once they’re out there, why would they stop in their task? So it just makes the lack of Type III civilisations even more puzzling to me.

    @ Al Jackson
    How likely is it that we’d find a black hole rotating at almost the speed of light? Kip Thorne had to invoke a rapidly rotating black hole to solve some of the scientific challenges in ‘Interstellar’, but I got the impression that such fast rotators are fairly unlikely – unless a black hole can be built artificially and designed to spin fast?

    @ Mark Zambelli
    Some elliptical galaxies have more dust than others. It depends on how they were formed, whether they formed directly in the early Universe or coalesced from two merging and dusty spiral galaxies. Even if they lack lots of dust though, recent results have shown that the likes of carbon and water can form in large quantities even in the early Universe, and planets seem to have been able to form early too. Whether elliptical galaxies would have had all the materials they need for life, I don’t know, but they would definitely be worth looking at just in case.

  • swage May 11, 2015, 8:03

    The main pitfall here is that the Kardashev Scale is an energy scale. I know this goes back to Sagan and lately Hawking (ultimately to Freeman Dyson, of course), but considering energy need is different from considering cosmic expansion of a civilization, if the civilization category is correctly applied here in any case.

    Its like making a claim that you need at least steam engines to cross the pacific, quite possibly without being aware of nuclear power.

    So we are not utilizing the entire power of the planet, but our reach extends through our solar system already. We don’t need to utilize all the energy resources on the planet to do that, nor should we. Is that even possible? There is a problem here.

    Efficiency makes things easier. That is why there are Robots on Mars and not humans. If you can shave off mass, either by going robotics or nano or leaving your engine at home or by using some kind of ingenious system fusion things become incredibly easier. But your energy footprint is reduced, which is a desirable effect after all, isn’t it?

    What we are really looking for is a scale for galactic colonization and spatial expansion, not so much energy. It is intertwined to energy need, of course, but it isn’t necessarily the prime determining factor. This could be, and after all, if we look at our own progress, IS most likely an mistake.

    There is another pitfall regarding detecting radio signals from another civilization and the inverse square law. I don’t want to roll it up again in its entirety, but it comes down to being extremely difficult to detect a mirror civilization (to ours) at roughly a light year and beyond.

    The third one is taking the Drake Equation to infer any kind of statistical argument about space faring species and their technology. We have arguably one data point (us). You can not do a meaningful statistic from one data point. But we made some progress regarding (potentially) habitable planet density through Kepler and the tendency for high values, based on our current impressions, largely dependent on our models, is quite interesting.

    The question if it is widely inhabited (it is obviously inhabited by at least us) and if so, by what exactly, that’s something we will explore further and not something we need an excuse for to turn away from.

    Dr. Zubrin is talking about a snowday in a quite similar context (manned Mars missions, actually). Reported with all the sincerity of a nine year old, telling the parents children shouldn’t go to school because it is too dangerous. The same thing is happening here.

    Someone or something might still utilize all galaxies in some unknown way, in which case it might be really difficult to spot the difference because we have no “normalized” ones to compare to. Even if that isn’t the case, which is pretty reasonable, we still do not know what exactly we are looking for.

    No Kardashev type III in our visible horizon does just mean exactly that. It doesn’t say a thing about anything else. We don’t exactly know that awfully much about galaxy cores or the universe itself for that matter. Lets not jump to conclusions that rashly.

  • RobFlores May 11, 2015, 11:19

    There is one more Impetus that has not been mentioned.

    I was rereading Ian Banks Novel Consider Phlebas
    and one race did expand as matter of RELIGIOUS proselytizing policy
    This type of expansion, would continue until it encounters a more powerful
    civilization is encountered. By natural selection it would not be absolute
    in nature and would curb itself when aggression is met with threat of
    utter annihilation by greatly superior civs that could wipe them out with
    a mere swish of it’s tail.

  • Alex Tolley May 11, 2015, 11:57

    If the holographic universe theory is true, and the aliens reside in the hologram space, rather than we do within the projection, is there any way that we could detect that? I appreciate that this means we could be alone in the universe, unless all ETIs eventually discover how they can “transcend” (or are “transcended”) to the hologram space.

    There are a lot of ways that advanced ETI might “disappear from view”, so energy harvesting KIIIs becomes an idea that is searchable, rather than one that necessarily makes sense, except from our somewhat primitive developmental stage. That doesn’t mean we shouldn’t look, just that that we are looking under the proverbial lamp post at night.

  • James Stilwell May 11, 2015, 12:05

    It seems oddly confusing to picture a cohesive galactic civilization requiring 100,000 years to pass before the western rim people know what is happening in the eastern rim…will someone please step forward and put the Bell Theorem to work…faster than light communication would be a start.

  • Mark Zambelli May 11, 2015, 12:17

    Keith Cooper says…
    “…such fast rotators are fairly unlikely – unless a black hole can be built artificially and designed to spin fast.”

    While it seems possible to collapse even a 10kg lump of anything by pumping enough energy into a small enough volume (maybe using a solar collector inside Mercury’s orbit for example; spin rate could probably be engineered to taste) this will only produce a microscopic BH that may be suitable for a propulsion system only, due to the Hawking Radiation.

    Finding a natural stellar-mass BH would obviously be what’s needed. Nature does a good job spinning-up accreting rotators so an accretion-disc would be needed. Maybe an X-ray binary like Cygnus X1 migh spin up a BH to give more return. Have no idea though how you would spin one up for less energy than you want to eventually harvest, or even the mechanism for that. If any KII sentients know the answer, please drop us a line ;)

  • swage May 11, 2015, 13:49

    Uhm… well, depends on what kind of BH we are talking about. Kerr BHs are rotating, so you don’t need an artificial one, in any case. It comes with the accreditation of matter, i guess. I’d say, and i lean a bit out of the window here, most of them spin at relativistic speeds, and probably only because they simply can not go faster than light speed (Lorenz Factor). Active and inactive galactic nuclei are an active field of research and i’s suggest if you want a really up to date assessment you ask Hawking directly.

  • Al Jackson May 11, 2015, 18:16

    @ Keith Cooper
    As a general rule the formation of stars, neutron stars and black holes involves matter that has angular momentum. The more compact they become the faster they spin. In the case of black holes (and neutron stars) they can also be spun-up by the accretion of matter. The ability to measure the spins of black hole has only become reliable in the last 10 or so years. There are about 20 black holes which have been measured and they range from .3 to .95 of the max spin rate. Famous Cygnus X-1 has a spin of .97, GRS 1915+105 has a spin of .98 and GRO J1655−40 spin at .98. Remember the spin rate at maximum implies the ‘swirl’ space around that kind of a black is traveling ~ the speed of light.

    The Masses and Spins of Neutron Stars and Stellar-Mass Black Holes
    http://arxiv.org/pdf/1408.4145v1.pdf

  • Eniac May 12, 2015, 0:03

    James Stillwell:

    It seems oddly confusing to picture a cohesive galactic civilization requiring 100,000 years to pass before the western rim people know what is happening in the eastern rim

    Confusing, indeed. Obviously, there cannot be such a thing. Cohesive civilizations will remain constrained to single star systems, most likely.

    That, however, will not keep them from spreading to eventually become 300 billion independent civilizations, one (or more) for each star system in the galaxy. Keith’s argument is valid if you assume that a large percentage of these would eventually max out their available energy, after a sufficiently long time. Not a bad assumption at all, in my opinion.

    As to black holes, most of these civilizations would have to make do without one. Even if they wanted to move (move an entire civilization? With nobody staying behind? I don’t think so) to where a stellar mass black hole is, they would likely find it already in use.