Brad Templeton on Dark Aliens

For more than fifty years, radio astronomers have scanned the sky in a quest to detect signals from alien technological civilisations, an effort called the Search for Extra-Terrestrial Intelligence (SETI). More recently, searches have expanded to include optical signals, signs of construction of alien “megastructures” and other “technosignatures”. So far, all of these searches have come up empty: have we simply not searched widely enough (you wouldn’t be surprised, for example, if you sampled one litre of the ocean at random and failed to find a fish in it), are we naïve to think advanced aliens would use primitive communication technologies like those we’ve just recently invented, or are we truly alone in the galaxy or the universe?

Brad Templeton suggests we may be looking in the wrong places. Human history on Earth suggests that as civilisations develop, they do so by exploiting energy sources at their disposal, are constrained by available energy, and seek new sources of energy. All human (and terrestrial) life is made of, and powered by, matter and energy composed of “baryonic matter” which, astronomers have discovered, makes up only about 5% of the mass of the universe. “Dark matter”, much of whose composition remains a mystery, accounts for 25% of the universe’s mass—five times as much. Once a civilisation understands dark matter, they’re immediately going to ask “What is it good for?” (and then, the moment they figure out, their “leaders” will ask “How can we tax it?”). Anyway, if there’s a way to extract energy from dark matter (and several speculative schemes have been suggested), there is five times as much of it as in all of the stars, planets, asteroids, and interstellar and intergalactic gas in the visible universe.

Once aliens become sufficiently advanced to exploit dark matter, mightn’t they (in all probability, machine intelligences) go where the energy is, far from profligate stars, and harvest the true wealth of the universe—energy from dark matter. This is not to suggest the aliens are made of dark matter, although that is also a possibility.

(What about the other 70% of the mass of the universe? That’s called “dark energy”, and we don’t know enough about it to guess how it might be exploited. If the most popular theory about it [“a cosmological constant”], it does not appear to be usable as an energy source since it would be absolutely evenly distributed throughout the universe.)


Is dark energy related to energy posited to exist in the zero point field? I think Bernard Haisch has suggested this might be an exploitable kind of energy.


I know this is one of those topics on which I understand I differ from out host, whose opinions & assessments on most other topics I respect deeply.

When the current consensus tells us that the majority of the mass of the Universe is invisible, and that that invisible matter is itself dwarfed by the amount of mysterious repulsive gravity energy – I can’t help but think of phlogiston, or the aether, or any of the other ideas which were once accepted thinking by serious people.

Carnot developed the equation for the efficiency of a heat engine which we still use today – but he based this on an entirely incorrect understanding of the nature of heat. Newton developed his action-at-a-distance theory of gravity which reigned supreme for centuries based on an incomplete understanding of the phenomenon. The fact that a theory fits certain observations does not guarantee that the theory is correct. It would hardly be surprising if future developments relegate dark matter & dark energy to the position in the history of science now occupied by the aether.


The most common hypothesis for the nature of dark matter is an Einstein-style cosmological constant, which is an energy of empty space independent of its contents, that acts as a gravitationally repulsive field. Because its energy is constant in all volumes of space, as the universe expands, the repulsive force becomes larger with respect to the gravitational attraction among baryonic and dark matter, and eventually tips the universe over into accelerating expansion, as is observed.

A cosmological constant is the simplest known explanation for the accelerating expansion of the universe. There are any number of other mechanisms consistent with the observations (for example, an energy field that evolves with the age/size of the universe, a repulsive force generated by some unknown particle, round-off in the computer running the simulation, etc.), but until and unless they make predictions which observation shows are distinguishable and more accurate from those of the simple cosmological constant, Occam’s razor argues for the simplest explanation as the working model.

A cosmological constant is deeply related to the energy of the quantum vacuum described by quantum field theory. However, a straightforward calculation of the vacuum energy density based upon the particles and forces known to physics yields a result which differs from the observed apparent cosmological constant by around 120 orders of magnitude (a factor of 10^{120}). This is called the “cosmological constant problem”, and is the most egregious example of apparent fine-tuning in cosmology.


One of the factors which makes me wonder about invisible dark matter – its distribution.

There is an apparent anomaly in the movement of stars around a galaxy. In a simple system like the solar system, the planets further from the center of mass (ie the Sun) move more slowly than the planets closer to the center of mass, in perfect accordance with the laws of gravity. Since we can see that the bulk of the (visible) mass of a galaxy is concentrated in its center, it would thus be intuitively reasonable to expect that stars further from the center of a galaxy would move more slowly. However, subtle measurements show this is not the case. Apparently, stars close to the center of a galaxy and at the edge of that galaxy rotate at the same speed. Strange!

The postulate of invisible dark matter is invoked to explain this anomaly. Supposedly, each galaxy is surrounded by a massive (but invisible) halo. The gravitational effect of this massive invisible halo would result in the anomalous movement of visible stars at the edge of galaxies. OK, it is a theory!

Invisible dark matter is postulated to have no interaction with electromagnetic vibrations, such as light. However, it is postulated to have normal interaction with visible matter via the force of gravity. OK, that is a postulate. The obvious question then is – Why does invisible dark matter end up as a halo outside the galaxy, instead of being concentrated by the force of gravity into the center of the galaxy in the same way as actual visible matter? The distribution of invisible dark matter in galaxies seems to be convenient, but inexplicable.

Recall the planet Vulcan, which (back in the days before Einstein) was postulated to explain the anomalous movements of the planet Mercury. Sometimes incomplete theories can lead to erroneous explanations.


Sure, but so what? The way science is done is by making observations, inventing models that attempt to explain them, making predictions from the models, then testing those predictions against future observations and new observations against the reigning model(s). This is how competing models (such as the steady state and big bang cosmologies) are winnowed down, how existing models are refined to accommodate new observations, or how long-accepted models are shown to be inadequate and motivate the search for a replacement (which, of course, by the principle of correspondence, must be consistent with all previous observations).

Newton’s theories of mechanics and gravitation perfectly explained all of the observations in existence at the time they were proposed. It took centuries until the precision of instruments and the patience of observers showed small discrepancies that required corrections. This doesn’t mean that Newton’s theories were wrong, or that people were foolish to believe them correct, or that other theories (such as the kinetic theory of gases) should not have been built on top of them. We now call Newton’s work effective theories, which means they accurately describe observations in a defined set of conditions (velocities not close to the speed of light and masses smaller than the Sun). Most physicists assume that all of our theories are effective theories and that when you look at energies, masses, etc. larger than explored, new phenomena will be observed that require new theories. That’s why they spend billions on things like the Large Hadron Collider.

We use the theories we have to explore the universe we inhabit, always on the lookout for places the theories break. To insist that we must discard the best theories we’ve found over the centuries as the foundation for experimentation in favour of some unknown idea yet to be invented would put an end to the scientific enterprise just as surely as discarding test by observation in favour of reliance upon divine scripture.

For example, consider dark matter. It was first proposed in the 1920s and 1930s to explain how the velocities of stars within the galaxy and galaxies within clusters were consistent with those structures being gravitationally bound. In successive decades, observations of the rotation curves of galaxies, gravitational lensing by massive galaxies, and the distribution of anisotropies in the cosmic background radiation all indicated the presence of invisible matter around five times that of all conventional baryonic matter. These values were consistent with one another. Since then, numerous other theories have been proposed to explain the observations without invoking dark matter, for instance modified Newtonian dynamics (MOND). To date, none of these theories reproduces the observed results which are consistent with the presence of dark matter. This, not a vast conspiracy of establishment cosmologists, is why dark matter is the current best explanation for the observations in hand.


This has been modeled in detail for decades by massive computer simulations of the evolution of the universe from small density perturbations in the big bang to the formation of galaxies, clusters of galaxies, and superclusters strong along a cosmic web, with dark matter playing the central part in the formation of the large-scale structure. All of the simulations have shown that if you take out the dark matter and simulate only baryonic matter, you get results that don’t look anything like the universe we observe. Put in the dark matter, in the fraction suggested by other completely unrelated observations, and the simulation comes out with something close to what we see.

The obvious answer to the question as to why dark matter remains in a halo is the very same answer as to why it’s “dark” (actually, transparent). It doesn’t interact, either with regular matter or with itself. With no way to interact, it doesn’t “clump”, as it has no way to shed its angular momentum. Gravity, to which it responds, will pull it together into the cosmic web and around galaxies and clusters, but it doesn’t clump further due to lack of interaction. Regular matter, however, is subject to clumping due to electromagnetic (chemical) forces, friction, collision, etc., and this causes it to condense into structures such as galaxies, stars, and protoplanetary discs.


I’m pretty confident the empty space energy is actually a hypothesis for dark energy, not dark matter.

Of course the whole reason we call them ‘dark’ is because we don’t know what they are, but we can see their influence.


One of the factors which makes me wonder about invisible dark matter – its distribution.

Indeed, I did some back of the envelope calculations that based on the estimated distribution of dark matter in the galaxy, the sphere that fits our solar system would have less dark matter than the mass of Ceres. Spread out over an enormous volume. Please feel free to check me and correct me if I’m wrong on that.

The obvious question then is – Why does invisible dark matter end up as a halo outside the galaxy, instead of being concentrated by the force of gravity into the center of the galaxy in the same way as actual visible matter? The distribution of invisible dark matter in galaxies seems to be convenient, but inexplicable.

Gravity only concentrates things because of collisions, which tend to cancel out most motion other than the dominant angular momentum. Dark matter is hypothesized to have very small cross section, so even collisions are quite rare. My understanding of the current hypothesis is that it is more concentrated toward the center of the galaxy, but the halo extends about 30% outside what we consider the normal edge of the galaxy.

However, that’s based on curve fitting and models, what properties would be needed to explain galactic rotating under our current theory of gravity. It’s why there are efforts to directly detect dark matter to confirm something is really there, etc. If those experiments make it less and less likely that dark matter can be detected, we’ll eventually have to discard it like string theory.


Just so! It is possible to develop an explanation of an observed phenomenon by making the appropriate assumptions in a theoretical model. Hence the (non-existent) planet Vulcan orbiting between Mercury and the Sun. Hence also the Catastrophic Anthropogenic Global Warming predicted by massive computer models. Caveat emptor!

The basic consequence of gravity is that bodies with mass are attracted towards each other. Hence we are standing on the surface of Planet Earth. Undoubtedly, it is possible to set up giant computer models which somehow show invisible dark matter being sufficiently attractive to organize itself into a huge Saturn’s rings type of halo around galaxies of visible matter rather than getting attracted into the center of visible mass. We can ascribe any properties we want to invisible dark matter to make the theory fit the observations. That kind of computer model prediction is in the same class as the General Circulation Model predictions of Catastrophic Anthropogenic Global Warming – it may be correct, but then again, maybe not.

All I am really suggesting is that a certain amount of healthy “Show Me” skepticism is in order when looking at a postulated phenomenon such as invisible dark matter.


There is some evidence for something out there causing gravitational lensing that exceeds the visible matter, which Dark Matter would explain and would also support the small cross section (the Bullet Cluster being the primary example) where it seems to have a smaller cross section than interstellar dust.


Absolutely! We know that our current theories/models are incomplete at best. Hence our host’s reminder about the 120 orders of magnitude difference between theory & observation for the apparent cosmological constant. All I am suggesting is – Let’s not say “Dark Matter”, case closed. Because the case is obviously not closed. Open minds! It is what science is all about!

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Joining late … and I will later release a more detailed article on this … I note a fair bit of discussion on whether dark matter is real or not. This is of course still debated, though the presence of a small number of galaxies that do not appear to have missing mass does strongly suggest it’s real. However, some other core points remain true. Stars are only a fraction (around 1/5th to 1/2) of the hydrogen in the universe, and hydrogen fusion which powers all light and everything else we see extracts only 1/150th of the usable mc^2 energy in that hydrogen.

So while we focus all our attention on where the literal light is, that light represents a tiny fraction of the available energy out there, and as such it is very likely that advanced ETI, which would seek to be efficient and thus dark (in the classical sense of not emitting waste energy) might be mostly likely to found where the light isn’t, but we search only where it is.

As I discuss, that does leave open the question of why they are not also exploiting the 1/300th of the energy which is found in the light we can see, and I offer a variety of possible explanations though no clearly evident one.


If you are correct and the advanced ETI would seek to be efficient, wouldn’t one expect a gradient of intelligence such that the slightly less advanced ETI would not yet make it to the dark?


Our ability to observe these intermediately advanced ETIs would depend upon how long they stay in that state. If their history includes an “intelligence explosion” in which the computational resources at their disposal rapidly approaches the physical limits of computation, and in this process they discover how to exploit the energy from dark matter, the period between their acquiring the capability to expand outward and going dark to our SETI observations may be sufficiently short that the chance of catching them in that state is very low.

Something like this has happened with terrestrial technology. The Earth was radio-loud only for about a century, with terrestrial fibre optics supplanting high-power broadcasting and satellite communications using only modest power and encodings which, being very efficient, are almost indistinguishable from noise. An alien SETI search looking for “leakage” from our FM and television broadcasts of the 20th century would have only a very short window in which to catch them.

One of the things I found fascinating (if a bit creepy) in Brad Templeton’s presentation was the suggestion that the rare galaxies we find that seem to have no dark matter (research paper) may have been “mined out” by the dark aliens, who have moved on to greener pastures.


I do propose that physics is finite and takes a relatively short time to understand nearly completely. We’ve only be at it for a few centuries and do not understand it fully but seem to have gotten a fair bit of it – or so we hope. Expanding a civilization out into your galaxy is limited by the speed of light. You need advanced tech for thousands of years to colonize a sphere thousands of LY across. If you are less advanced by then you will lose out to more advanced competitors you intersect, or you allow to grow within your sphere.

If there are “less advanced” beings what makes them dark is if they are too efficient for us to see with our current techniques. They might be visible to others of their own level, or greater. They might even be visible to us in 100 years as we get better at observing. Very efficient civilizations would emit waste radiation at high entropy that’s hard to tell from the cosmic background. At least hard for us to tell.


You have all been deceived from the first principles. The idea of “curved spacetime” is illogical, an outrageous attack on the human psyche. Anyone who believes in such nonsense is seen by the deceivers as fair game for more deceptions that follow. You can no more unite the measurement of space with the measurement of time than you can unite taste with sound or voltage with weight or any other pair of unrelated measures.

Those of us who retain a healthy “show me” skepticism about the hypothesis of invisible dark matter – the few, the proud – might alternatively suggest that perhaps the presence of galaxies inconsistent with invisible dark matter indicates that the theory of invisible dark matter leading to the concentration of visible real matter into galaxies is … incomplete.

But let’s assume that a super-advanced alien civilization “mined out” the invisible dark matter in the hypothesized halo thousands of light years across which originally surrounded a galaxy, and used the annihilation of such matter (several times the mass of the observable galaxy) to generate a truly cosmic amount of energy: then surely the release of such an incomprehensible amount of energy would have generated observable effects, such as e.g. temperature anomalies, even allowing for the aliens’ process having taken millions of years?


The observability of an energy release would depend upon how efficiently the energy was extracted. If the aliens value efficiency—converting as close as possible to 100% of the energy available into useful work—highly, they they will try to extract the energy while using the photon sea of the cosmic background radiation as the cold sink of their heat engine. That would mean that their activities would not produce a heat signature we might be able to detect in our present-day surveys of the cosmic background radiation.

This is, of course, piling speculation upon speculation: that dark matter is something from which energy can be extracted, that aliens exist and have mastered the trick, and that the aliens have achieved almost perfect efficiency in extracting the energy. Note that they would not need to be motivated by stealth in reducing the temperature of their waste heat. To the extent they improve efficiency, they automatically reduce their thermal signature.

Detecting advanced civilisations by their waste heat emissions is not a new idea. In 2015, a paper, “The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies”, reported an infrared survey of around 100,000 galaxies looking for sources with signatures indicative of reprocessing sunlight into mid-infrared. Here is the abstract:

Nearby Type III (galaxy-spanning) Kardashev supercivilizations would have high mid-infrared (MIR) luminosities. We have used the Wide-field Infrared Survey Explorer (WISE) to survey \sim 1\times 10^5 galaxies for extreme MIR emission, 10^3 times more galaxies than the only previous such search. We have calibrated the WISE All-sky Catalog pipeline products to improve its photometry for extended sources. We present 563 extended sources with |b|≥10 and red MIR colors, having visually vetted them to remove artifacts. No galaxies in our sample host an alien civilization reprocessing more than 85% of its starlight into the MIR, and only 50 galaxies, including Arp 220, have MIR luminosities consistent with >50% reprocessing. Ninety of these (likely) extragalactic sources have little literature presence; in most cases they are likely barely resolved galaxies or pairs of galaxies undergoing large amounts of star formation. Five are new to science and deserve further study. The Be star 48 Librae sits within a MIR nebula, and we suggest that it may be creating dust. WISE, 2MASS, and Spitzer imagery shows that IRAS 04287+6444 is consistent with a previously unnoticed, heavily extinguished cluster of young stellar objects. We identify five “passive” (i.e. red) spiral galaxies with unusually high MIR and low NUV luminosity. We search a set of optically “dark” HI galaxies for MIR emission, and find none. These 90 poorly understood sources and five anomalous passive spirals deserve follow-up via both SETI and conventional astrophysics.

This search assumed the civilisation would reject heat at something like the temperature of liquid water. If waste heat was near the temperature of the cosmic background radiation, it would not be detected.


This is stupid, boring, and not even funny. People do not come here to be bored. I have silenced this account.