The idea of moving stars as a way of concentrating mass for use by an advanced civilization – the topic of recent posts here – forces the question of whether such an effort wouldn’t be observable even by our far less advanced astronomy. In his paper on life’s response to dark energy and the need to offset the accelerating expansion of the cosmos, Dan Hooper analyzed the possibilities, pointing out that cultures billions of years older than our own may already be engaged in such activities. Can we see them?
I like Centauri Dreams reader Andrew Palfreyman’s comment that what astronomers know as the ‘Great Attractor’ is conceivably a technosignature, “albeit on a scale somewhat more grand than that cited.” An interesting thought! And sure, as some have pointed out, nudging these concepts around on a mental chess board is wildly speculative, but in the spirit of good science fiction, I say why not? We have a universe far older than our own planet with possibilities we might as well imagine.
If we turn our attention in the general direction of the constellation Centaurus and then look not at the paltry 4.3 light year distance of Alpha Centauri but 150–250 million light years from Earth, we encounter a region of mass concentration that folds within the Laniakea Supercluster. The latter is galactic structure at an extraordinary level, as it takes in some 100,000 galaxies including the Virgo Supercluster, and that means it takes in the Local Group and the Milky Way as well.
What’s happening is that this hard to observe region (it’s blocked by our own galaxy’s gas and dust) is evidently drawing many galaxies including the Milky Way towards itself. The speed of this motion is about 600 kilometers per second. Bear in mind that the Shapley Supercluster lies beyond the Great Attractor and is also implicated in the motion of galaxies and galaxy clusters in this direction. So the science fictional scenario has a civilization clustering matter at the largest scale to avoid the effects of the accelerating expansion that will eventually cut off anything that is not gravitationally bound. Cluster enough stars and you maintain your energy sources.
Image: Located on the border of Triangulum Australe (The Southern Triangle) and Norma (The Carpenter’s Square), this field covers part of the Norma Cluster (Abell 3627) as well as a dense area of our own galaxy, the Milky Way. The Norma Cluster is the closest massive galaxy cluster to the Milky Way, and lies about 220 million light-years away. The enormous mass concentrated here, and the consequent gravitational attraction, mean that this region of space is known to astronomers as the Great Attractor, and it dominates our region of the Universe. The largest galaxy visible in this image is ESO 137-002, a spiral galaxy seen edge on. In this image from Hubble, we see large regions of dust across the galaxy’s bulge. What we do not see here is the tail of glowing X-rays that has been observed extending out of the galaxy — but which is invisible to an optical telescope like Hubble. Credit: ESA/Hubble & NASA.
Recall the parameters of Dan Hooper’s paper, which posits the collection of stars in the range of 0.2 to 1 solar mass as the most attractive targets. The constraint is needed because high-mass stars will have lifetimes too short to make the journey (Hooper posits 0.1 c as the highest velocity available) to the collection zone. The idea is that the civilization will enclose lower-mass stars in something like Dyson Spheres, using these to collect the energy needed for propulsion of the stars themselves. Not your standard Dyson Sphere, but astronomical objects using propulsion that may be detectable.
Hooper doesn’t wade too deep into these waters, but here’s his thought on technosignatures:
From our vantage point, such a civilization would appear as a extended region, tens of Mpc in radius, with few or no perceivable stars lighter than approximately ∼2M☉ (as such stars will be surrounded by Dyson Spheres). Furthermore, unlike traditional Dyson Spheres, those stars that are currently en route to the central civilization could be visible as a result of the propulsion that they are currently undergoing. The propellant could plausibly take a wide range of forms, and we do not speculate here about its spectral or other signatures. That being said, such acceleration would necessarily require large amounts of energy and likely produce significant fluxes of electromagnetic radiation.
This is a different take on searching for Dyson Spheres than has been employed in the past, for in the ‘star harvesting’ scenario of Hooper, the spectrum of starlight from a galaxy that has already been harvested would be dominated by massive stars, with the lower mass stars being already enclosed. On this score, it’s also interesting to consider the continuing work of Jason Wright at Penn State, where an analysis of Dyson Spheres as potential energy extractors and computational engines is changing our previous conception of these objects, resulting in smaller, hotter observational signatures.
In the near future we’ll dig into the Wright paper, but for today it’s useful indeed, because it points to why we speculate on such a grand scale. Let me quote from its conclusion:
Real technological development around a star will be subject to many constraints and practical considerations that we probably cannot guess. While we have outlined the ultimate physical limits of Dyson spheres, consistent with Dyson’s philosophy and subject only to weak assumptions that there is a cost to acquiring mass, if real Dyson spheres exist, they might be quite different than we have imagined here.
And the key point:
Nonetheless, these conclusions can guide speculation into the nature of what sorts of Dyson spheres might exist, help interpret upper limits set by search programs, and potentially guide future searches.
But back to Hooper and the subject of Deep Time. For Hooper’s calculation is that all stars that are not gravitationally bound to the Local Group (which includes the Milky Way and Andromeda, among other things) will move beyond the cosmic horizon due to accelerating expansion on a timescale of 100 billion years. It will be autumn among the galaxy clusters, meaning that their energies will need to be harvested or rendered forever inaccessible. Our hypothetical advanced civilization will need to begin moving stars back toward their culture’s central hub. Hooper sees a civilization conducting such activities out to a range of several tens of Mpc, which boosts the total amount of energy available in the culture’s future by a factor of several thousand.
This is an application of Dyson Spheres far different from what Freeman Dyson worked with, and I agree with Jason Wright that technologies of this order are probably far beyond our current imaginings. But as Dyson himself said in a 1966 tribute to Hans Bethe: “My rule is, there is nothing so big nor so crazy that one out of a million technological societies may not feel itself driven to do, provided it is physically possible.”
The paper is Hooper, “Life versus dark energy: How an advanced civilization could resist the accelerating expansion of the universe,” Physics of the Dark Universe Volume 22 (December 2018), pp. 74-79. Abstract / Preprint. The Wright paper is “Application of the Thermodynamics of Radiation to Dyson Spheres as Work Extractors and Computational Engines, and their Observational Consequences,” The Astrophysical Journal Volume 956, No. 1 (5 October 2023), 34 (full text). I drew the Dyson quote from Wright’s paper, but its source is Dyson, Perspectives in modern physics: Essays in Honor of Hans A. Bethe on the Occasion of his 60th birthday, ed R. Marshak, J. Blaker and H. Bethe (New York: Interscience Publishers) July, 1966, p. 641.
Collecting 100 000 galaxies together is a dangerous game to be played by a civilization. It will be increasingly difficult to counteract the constantly growing gravitational attraction, leading to a gigantic black hole. I would consider an artificial formation to be one where the gravitational force exactly or almost exactly counteracts the dark energy expansion. Such a formation could outlive the universe expansion, not one that contracts gravitationally.
My naive understanding of DE is that it is a fundamental property of space and therefore expands everything, eventually leading to the “Big Rip” that would expand even BHs. Yes, increasing the local gravitational attraction will probably temporarily slow down the expansion between galaxies (that should be observable even now), but it will not overcome the fundamental expansion of space over time (assuming that DE continues the expansion rate increase indefinitely).
I would have thought that simply creating a large BH like the ones at the center of many galaxies was the best holding action, keeping the civilization close to the event horizon to resist the expansion as long as possible. Why go to the trouble of harvesting stars for energy if the 2ndry purpose is to increase the mass of the home galaxy to resist the expansion? Just use up the stars in the home galaxy first.
This logic implies that creating huge BHs in the center of galaxies is the strategy, and therefore their presence in so many galaxies is evidence for ETI, whether a single species spreading throughout the universe or many species, each in their home galaxy, executing the same local strategy.
Nobody knows what DE is, but when it was first suggested by Einstein (his “biggest mistake”) it was to counteract gravity and make the Universe static, or metastable (it cannot be stable even with DE). So, a mass distribution that counteracts DE is allowed by Genral Relativity.
Just 100 years ago this month, Edwin Hubble announced the existence of other galaxies beyond the Milky Way. In other words, it has been less than a century since we learned that we live in a universe filled with galaxies beyond our own.
At one time, it was believed that Mars had aliens living on it, with seasonal changes that turned the planet green and canals built to irrigate its dry regions.
I doubt that dark energy or dark matter is necessary, as we have a very limited understanding of the universe and how it works. I think we may find tecnosignatures much closer to our home world than we think.
Superluminal soliton warp bubbles need immense amounts of energy to warp and to stop warping, and we have a possible source for that. The perfect place to find these energy levels is right in front of us every day.
Every other solar system has that energy source available, and soliton warp bubbles could potentially pass through a star like our Sun. We often assume it’s impossible, but this concept may not be as far-fetched as it seems. These crafts operate outside the realm of what we normally perceive and would likely have no problem navigating such environments.
There was a video showing the Sun experiencing a huge explosive flare and a coronal mass ejection (CME) on one side, followed instantly by another massive flare and CME on the opposite side. Is this just a coincidence, or could it be a technosignature?
What do we have every year or two in our heavens that astounds us, the very rare coincidence of a black hole in our skies…
On a sufficiently large scale (in terms of the observer) the artificiality of phenomena might be missed.
Yes. If we use the ant near the freeway analogy, the “ant scientist” might wonder why the air tastes different during the day, why strange compounds seep into the nest, are the large objects passing by somehow the taste of the air, etc, etc. The ant does not know about the beings who create the smooth surface and navigate the huge objects upon it.
We may be in a similar situation, albeit with bigger brains, imaginations, and means to test ideas and speculations. We do assume that the universe is not artificial and operates under natural laws. It takes almost unassailable evidence to counter that narrative. I don’t know what would be convincing evidence that hypervelocity stars are being controlled by intelligence and not by random natural forces, or that whole galaxies moving contrary to the general expansion are similarly controlled. And of course, if the universe itself is a simulation…
We only have one example, our own, to draw on, but it seems reasonable to assume technological change is relatively slow to get started, but does speed up eventually. Check out Britannica to get some idea:
https://www.britannica.com/story/history-of-technology-timeline
But as technology accumulates, it provides tools useful to generate additional and unexpected technology. It took millions of years to go from flint tools to fire. Today, the whole world can change technologically in just one lifetime. I know, I retired ten years ago and after four decades in high tech all my job skills are now obsolete! I can operate a slide rule, drive a manual transmission, navigate with a sextant and code in Fortran, but I can’t program my smart TV. I believe we are now very close to the point where the technological environment is changing faster than we can adapt to it individuals, or our social institutions can keep up with it.
It is not unreasonable to assume that this state of affairs is not peculiar to genus Homo, but is a characteristic of all technical species everywhere. Can technology become more and more capable indefinitely if its users are incapable of learning how to use it? We are now realizing it has the capability to even destroy us.
I find it difficult to believe there are mega-civilizations out there capable of carrying out the extravagant engineering feats we have been discussing here in the last few articles. I don’t doubt its possible to harness the energy resources of an entire planet (or star, or galaxy), I just doubt any social system can change fast enough to exploit those accomplishments, or any organism (biological or mechanical) to accommodate them. We must not fall into the trap of thinking technological change can continue to expand indefinitely without eventually tearing apart the civilization it inhabits. Nothing in nature undergoes exponential growth forever.
What I believe is much more likely is that a truly advanced (wise) culture would learn how to manage this process in such a way that is orderly and controlled and does not shake itself to pieces; “Do we really need so much computational capability (or transportation requirements) that we have to harness entire stars to power them?”
I feel truly intelligent species will instead concentrate on ways of avoiding these singularity traps by simply organizing their societies so they don’t need suicidal machines and processes. (“Hey, internal combustion is neat, but can we really handle the pollution, the infrastructure requirements, and the resource depletion it will inevitably lead to?” Remember, a truly advanced culture would have anticipated the costs as well as the benefits.
Folks, I know its tempting to believe that other civilizations will require massive energy-consuming technologies (so we’ll be able to detect their technosignatures over long distances with our meager tech). Even if they could, wouldn’t they be afraid their by-products might attract the attention of other, perhaps hostile, neighbors with even stronger capabilities.
There is another consideration as well. Perhaps tech CANNOT expand exponentially forever. Maybe an up-and-coming civilization will eventually pick up all the low-hanging fruit and then technological progress will stop or slowdown. The derivative of the acceleration is the jerk. Or perhaps the rate of increase of technological process will level off. I suspect there are natural laws which can be twisted to provide benefits like faster than light travel, or beam-me-up transporters or replicator technologies–but the engineering challenges are simply to great. For example, nature shows us thermonuclear fusion works, the stars do it, and we can make bombs and tokomaks, but the requirements to harness this tech for practical propulsion or power generation may simply be limited to temperatures and pressures which we cannot duplicate in power plants or space ships with any practicality. There is no way of knowing if fusion powered ships or fusion generated electricity will be commonplace ten years from now, or if they will never be available because materials do not exist in nature that can adapt it to industrial uses, but I think you catch my point. Just because something doesn’t violate the laws of nature doesn’t necessarily men we can eventually build one. Perhaps the only way we can duplicate the pressure-temperature conditions in stellar cores is with a fission trigger. Or maybe there are human limits. I know exactly how an internal combustion engine works, but I don’t know how to build one. Perhaps entire civilizations are prone to comparable limitations.
Maybe Kardashev I is likely. Perhaps Kardashev II is possible. But K III? I doubt it.
We can be pretty certain that if extra terrestrials exists, some of them will have mastered technologies far superior to ours, but we have no reason to believe that technology is guaranteed to expand forever, inevitably. Even Nature has built-in limits. So do critters.
@Henry
I don’t believe that is true. I agree as we get older it seems to get harder to learn new things. But some of this is inflicted upon us. Take online grocery shopping. Unlike autos, there are no standard interfaces. Every company has its own interface with its ordering quirks. There are obvious solutions. Firstly, as with autos, enforce industrywide standards. [Not going to happen.] Secondly, the complexity can be reduced with 3rd-party control of the interface. This is the Amazon approach. lastly is to have the smart computer assistant handle the complexities of the task “order my usual pickles from store [X].”
We are all products of the tools we use. You know Fortran, but presumably you don’t code in binary or assembly. Fortran is not useful for web page design, so other languages are used for that. This has created yet more complexity, which is periodically reduced with new tools, and currently with AI like MSoft’s Copilot to write the code. 20 years ago, there was a brief[?] period of designing what you wanted, and the code was generated automatically.
My guess is that skills will be subsumed by layers of “helpers”. I don’t code in Fortran, but ChatGPT can manage some basic/simple Fortran coding. We’ve all seen those amusing videos of children trying to work out how a rotary dial telephone works to make a call or a cassette player to play music. Had they been allowed to use YouTube, no doubt there is a video on how to do these things.
On to the question of slowing the pace of technology change to be more deliberate, something like the Amish do with new technology. I think simple social Darwinism prevents this from happening. Evolution doesn’t balance the short and long-term benefits, it just selects the short-term advantages that increase reproductive success. The same applies to business and economic systems. We can see that operating today the world is unable to effectively deal with the obvious long-term problems of climate change. We should be able to do the right thing, by those who gain by continuing to cause more CO2 emissions continue to disrupt any effective behavior change. The recent Cop29 meeting demonstrated this in spades.
The Europeans colonized the Americas and changed the continent. We enjoy a high standard of living compared to the indigenous peoples we displaced. But our behavior has potentially wrecked the sustainability of our civilization which might have been better served over the long term if we hadn’t. As our technologies increase in power, the existential risks to humanity (not to mention the biosphere) increase. A few hundred years of industrial civilization might give way to a reversion to savagery. A “golden age” of civilization come and gone in a cosmic eyeblink.
We have no idea what are the limits of technology, nor indeed what sort of domains technologies will operate in. Arthur C. Clarke’s “Profiles of the Future: An Inquiry into the Limits of the Possible” first published in 1962, was very limited in the areas of technology he looked at. He couldn’t even have conceived of the advances in molecular biology and what the ensuing emerging technologies could achieve (nor even in the updated 1999 edition as the Human Genome Project was close to finishing).
Our civilization is still trapped in an earlier age of thinking, with “growth” in all its aspects as paramount. One might even argue that technological growth and all these effects is not dissimilar to Dawkins’ “selfish gene”, an algorithmic impetus to increase its presence and impact, resistant to containment. It may, as others have suggested, account for the Fermi Paradox, with our civilization in the process of snuffing itself out. Or it may lead us to such Olympian heights of far greater power than any Gods we have ever dreamed about.
@Alex
The issue isn’t whether or not technology can continue expanding forever, it’s whether it SHOULD–or even whether it is necessary or desirable for it to do so. And as our capabilities increase and improve, the tempo of change increases, making all our past planning irrelevant.
The execution of mega projects will involve long time scales, and the acceleration of technological change make even short term projects vulnerable to obsolescence. Why plan a migration to another star system to avoid a solar catastrophe when it may be
possible to repair an unstable sun long before the fleets are ready.
Or why bother with terraforming Mars once FTL is discovered and New Earths (or orbital communities) are found in abundance just a few AU or light years away?
Big, expensive long term projects can become pointless boondoggles when a cheaper, faster alternative is discovered long before the big project is finished. And this is bound to happen as the speed of technological change increases along with the appearance of multiple cheaper and faster alternatives. Its the “Far Centaurus” effect. Why bother sinking vast resources into a big project when chances are you may not even need it, or even want it, long before it comes on line?
I once owned 33 1/3 LPs, but soon replaced my music collection with cassettes. Long before they wore out, 8-track cartridges became available. Before you know it, the CD came along. Now people don’t buy recorded music media at all, they rent and download instead. I know, the LP is making a comeback, but I’m sticking with CDs.
The point I’m trying to make is that the speed at which new technology will become available in the future makes it extremely problematic to initiate any new. long term, complex, technological enterprises. This will only get worse as our science improves..
Technology, especially that which is promoted by starry-eyed enthusiasts (space groupies?), paranoid militarists and voracious and irresponsible commercial interests is not likely to be well integrated with the long term interests of the society. And nobody knows what our ‘long-term interests’ in deep time are even going to be. Billion Year Plans strike me as the ultimate in hubris. And what makes us think the Hive Entity in the Magellanic Clouds even has space groupies, paranoid militarists or voracious capitalists?
Ancient and highly advanced civilizations will know better than to plan in detail for emergencies that will not materialize for billions of years.
@Henry
You are assuming that an ETI could act like the Amish – decide on new technologies to accept and go even further to control their [lack of] development. I don’t think that is possible, because as I stated, technology development is like evolution, an ever-exploding frontier of possibilities that provide short-term gains for the developer.
To halt technology development would require an extremely authoritarian, global [as in across the stellar polity], government. What sort of stagnant civilization would that be? They would always be wary that another civilization was not so restrictive and wipe them out with superior technology.
The terrestrial history of technology suggests that even when new technologies are available, they are not used for other reasons. For example, commercial air travel should be at least supersonic by now, if not hypersonic. But economics made that speed almost stillborn. If a plateauing technology stymies further profitable development, technology develops in another direction – e.g. microelectronics, biotech, etc. We have gone through waves of different technology areas, driven by opportunities to profit in our capitalistic system. While each poses existential risks, usually not appreciated until after the development has run its course, rarely has a technology been halted or delayed. Direct genetic manipulation in humans was prevented by a voluntary code of ethics (1975 Asilomar conference on genetic recombination), but not entirely obeyed globally.
Regarding our ability to handle change. We do what every culture has done as complexity increases – atomize the functions each individual needs to be competent at and create methods of interchange so that competent people can be called on to handle a specific problem. We have trades, and specialists for all sorts of technology and issues that an individual cannot hope to handle or learn. Fortunately, even older technologies are rarely lost, whether maintained as hobbies, or niche work opportunities. You recall that the Y2K issue pulled a lot of retired Cobol programmers to fix legacy code that would have failed as the century turned. Somebody has to make buggy whips for the current use of horse-drawn carriages.
So while we do try to control further technological development of some technologies – e.g. nuclear weapons, poison gases, lethal microbes, that cannot stop less lethal development in these domains, would we really want to halt our knowledge of molecular biology because someone could develop lethal plagues targeted at a population, even the global population for some ideological reason?
Bottom line, I find the idea of a “wise civilization” halting or at least severely controlling the development of, and possible use of, technologies that could pose existential risks, as unlikely. I know I would not like to live in such a civilization however comfortable it might be. It might be like the human civilization after the overlords arrived in Clarke’s “Childhood’s End”. How long could that last with little change? Thousands of years? Even a million years? Surely not a billion years or more.
At some point in the future it is logical to assume we can make propulsion which uses nuclear fusion when the technology becomes more efficient and advanced. We’ve covered that topic before on Centauri Dreams. We can carry our own stars with us. Consequently, the idea of seeing alien superstructures, Dyson spheres, etc. is obsolete today since it is trapped in our past technological limitations and knowledge. We have never had to harvest any energy due to technology which can manipulate the four forces of nature. Solar power is so easy and cheap since we don’t have to pay for solar radiation from the Sun.
If we learn how to make our own gravity and antigravity or space warp propulsion technology we won’t need to harvest it from empty space which may not have any energy capable of being harvested, so the cosmological expansion could be an illusion. The big freeze and dark end to our universe could be a subjective, jaded view of the cosmos which does not expand at all on the large scales, but only our pessimistic, unconscious projections onto it. It could be a living cosmos that is infinite, eternal and never dies.
Hi Paul
If anyone wants a copy of Dyson’s essay from the Bethe book you reference, I have it squirreled away somewhere. Discusses building an actual Dyson Sphere in some detail, so it’s not quite a truism that Dyson imagined a solid spherical habitat, rather than a Swarm.
Adam, the depth of your library on matters interstellar never ceases to amaze me!
Here is a paper by the late great Robert Bradbury who changed the paradigm on Dyson Spheres and Swarms into a Dyson Shell, also known as Matrioshka or Jupiter Brains:
https://gwern.net/doc/ai/scaling/hardware/1999-bradbury-matrioshkabrains.pdf
A popular news item on the subject from 2024 may be read here:
https://www.scienceabc.com/nature/universe/matrioshka-brain.html
To quote from the above piece:
“Billionaire entrepreneur Peter Diamandis recently created a company called Planetary Resources with the goal of mining asteroids to make the infrastructure for building a Dyson sphere. Another company with the name Made in Space is researching and working on designing 3D printing technology that would work in space with the ultimate motive of setting up factories that could replicate themselves in outer space.”
Instead of Dyson constructs as just habitats for intelligent species, these Dyson Shells would BE intelligent beings – Artilects on a vast scale able to think and do things way beyond anything we can do.
As for moving stars, how about if we move to where there are already a whole bunch of stars in a big group, namely open and globular star clusters? Bradbury thought of this plan too:
https://www.centauri-dreams.org/2016/01/06/globular-clusters-home-to-intelligent-life/
Here is a video of Freeman J. Dyson paying tribute to Hans Bethe at Cornell University in 2005:
https://ecommons.cornell.edu/items/da627dec-35ae-4904-bf4a-9f9b2dd3022e
Freeman Dyson’s Letters Offer Another Glimpse of Genius
By David Kaiser
March 5, 2020
“Here is a scientist who can really write,” the physicist Hans Bethe observed in his review of Freeman Dyson’s first book, “Disturbing the Universe,” in 1979.
https://www.newyorker.com/tech/annals-of-technology/freeman-dysons-letters-offer-another-glimpse-of-genius
Yes, we don’t know the first thing about DM, DE, fusion drives, whether any other civilization is even possible or how to detect them, what tech we’ll have even 100 years from now, etc. Yet we ponder these mighty things, throwing terms like trillions of trillions of years, and megaparsecs, and KIII civilizations around like candy wrappers.
We do this precisely because we don’t know. We have one miserable K0.7 data point to work with. But we do have a whole universe available for us to study. So we use our limited knowledge and our tiny intellects and make our imperfect assumptions to try to think how we might detect a second data point. Because we want to know. We need to know.
Just think, if we do find evidence of that second data point, boy how voracious our appetite for even more knowledge would become. How much more informed, and even more outrageous, our speculations, how frenzied we’d be looking for a third data point, and a fourth.
For now, all we know is that one K0.7 civilization exists. We have to work with that. Will technology just keep advancing ad infinitum by itself? No it will not. It takes the Musks and the Bezos’s, the Henry Fords and the Enzo Ferraris, the Teslas and the Edisons, to keep pushing the kart forward. And they need a reason to do so.
For Musk, he wants to solve humanity’s existential problems. That’s why he goes after electric cars. After making our species multiplanetary. That’s why he started Neuralink and why he bought Twitter, to try and improve our chances of a runaway AI not becoming hostile to us. Etc.
For most business people, there is probably a lot of the same motivations, but they wouldn’t be able or willing to do anything if it didn’t make business sense. Even for Musk. If he does build a city on Mars eventually, it will be because NASA contracted SpaceX to help put people on the Moon again. If we ever have companies mining asteroids, it will be because of Nasa enabling SpaceX to develop a cheaper way to get things into orbit.
But before there can be any sense for businesses to start developing space technologies, the big risks must first be taken by governments. They must fund the first long term bases on the Moon. And NASA only did the Apollo program because they were afraid of what the Soviets might do if they got there first. And now they do Artemis because they are afraid of what the Chinese might do if they industrialized the Moon first.
In the end this works to our advantage, as the new cheaper more powerful rockets, for which propellants can conceivably eventually be produced on the Moon or on Mars or on an asteroid, will enable the likes of NASA to take the risks to fund some big science missions to the outer planets again. But don’t be deceived, if it wasn’t for some kind of perceived threat, that wouldn’t happen, or it would take decades before we got one mission.
So will we get past K0.7? If the world suddenly went peaceful and we solved all our environmental issues, the answer is a firm no. If there is some kind of threat, then we might achieve multiplanetary status, we might build space habitats with material mined from asteroids, we might develop some kind of nuclear or beamed propulsion.
Will we reach Alpha Centauri? Not if there isn’t some big impending threat which will force the big governments to take the risk. Probably the only thing that will be sufficiently threatening is if we managed to detect an aggressively expanding K1.x civilization somewhere nearby.
But OK, say we do reach the point where we can send our machines to other stars, and do some large scale construction. And say we set our sights on building some sort of spider stellar engine.
Will we now travel 500 lightyears to the nearest neutron star, do you think? Or would it make more sense to travel 8 lightyears Sirius B, and construct some sort of engine there to push it closer to Sirius A so that it can steal material from it? Increase Sirius A’s lifespan and get Sirius B to the point where it will go SN, then we have a neutron star in our own backyard to work with.
It makes a lot more sense to me that, if we can manage to push stars around at all, we will start pushing our local group of stars into a tighter cluster to speed up communications and logistics. And then as we add more stars to the cluster, move gradually inwards to the central BH’s vicinity.
If we ever managed intergalactic travel, does it make more sense to go and harvest stars from other galaxies? Or will we build similar star clusters there and spiral them in towards the central BH there as well? And then later when we are K3.x if such a thing is even within the realms of possibility, push these BH’s in the direction of the great attractor?
And the galaxies which are on their way to disappear over the horizon? Which won’t make it however hard you pushed them towards us? Will we send our self replicating star harvesters there, to the billions of galaxies on the fringe, to crash all stars we can lay our hands on into the central BH’s, and beam all that energy towards our cluster?
Will we have to fight other K3.x’s who wants to beam energy to their own cluster beyond the horizon, to do so?
The potential technosignatures are legion. We need more telescopes, eyes and ears of every variety, so that we can look and hopefully, see.
I have a hard time picturing the ‘Great Attractor’ as a technosignature. My impression is that there is much work such as Sawala, 2021 that simulates how galaxies come together by ordinary applications of the Standard Model, including in the linked case differences in the distributions of spiral, elliptical, and disk galaxies relative to the supergalactic plane. We could get into the question of whether larger-scale features like the supergalactic plane are a technosignature, but if we go much further that way we’re back into the very old question of whether the Universe itself is a technosignature.
Customs, traditions, myths & narratives, laws and edicts all help to structure society and constitute culture. Technology tends to make an end-run around all of this.
The control of fire brought cooking, smaller teeth, altered oral cavities/vocal tracts contributing to speech, and the smelting of ores leading to iron and steel, Cryptocurrencies, while totally dependent on the grid, are able to swerve around and slip past financial regulation.
Technology moves faster than societal structures and culture, compelling their change. But it has reached a level where it is so energy and resource intensive that sustaining it is becoming problematic. As are its waste products. From the days of the first unicellular life the biosphere was a nearly closed cycle, with a notable exception of the Oxygen Catastrophe. We now produce waste in such quantities that the waste often exceeds what is utilized.
To reach a KI, KII or KIII civilization technology will have to be set upon itself – to fix the shortcomings.
Since we’re projecting civilizations of lifespan 10^8 or 10^9 years, we might speculate such a civilization learning to use dark energy, perhaps to such a degree that over time they consume enough dark energy to halt the expansion. Where does THAT level of engineering fall on the Kardashev scale??
https://astrobiology.com/2024/12/in-search-of-extraterrestrial-artificial-intelligence-through-the-dyson-sphere-like-structures-around-the-primordial-black-holes.html
In Search of Extraterrestrial Artificial Intelligence through the Dyson Sphere-like structures around the Primordial Black Holes
By Keith Cowing
Status Report
astro-ph.GA
December 5, 2024
Are we alone? It is a compelling question that human beings have confronted for centuries. The search for extraterrestrial life is a broad range of quests for finding the simple forms of life up to intelligent beings in the Universe.
The plausible assumption is that there is a chance that intelligent life will be followed by advanced civilization equipped or even dominated by artificial intelligence (AI). In this work, we categorize the advanced civilizations (on an equal footing, an AI-dominated civilization) on the Kardashev scale.
We propose a new scale known as space exploration distance to measure civilization advancement. We propose a relation between this length and the Kardashev scale. Then, we suggest the idea that advanced civilizations will use primordial black holes as sources of harvesting energy. We calculate the energy harvested by calculating the space exploration distance.
Finally, we propose an observational method to detect the possibility of extraterrestrial AI using Dyson spheres-like structures around primordial black holes in the Milky Way and other galaxies.
Shant Baghram
Comments: 9 pages, 2 figures. This paper has been accepted for publication in the Astrophysical Journal (ApJ)
Subjects: Astrophysics of Galaxies (astro-ph.GA); Instrumentation and Methods for Astrophysics (astro-ph.IM); Popular Physics (physics.pop-ph)
Cite as: arXiv:2412.02671 [astro-ph.GA] (or arXiv:2412.02671v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2412.02671
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Submission history
From: Shant Baghram
[v1] Tue, 3 Dec 2024 18:45:18 UTC (87 KB)
https://arxiv.org/abs/2412.02671
Astrobiology, SETI, Technosignature
https://astrobiology.com/2024/11/potential-technosignature-from-anomalously-low-deuterium-hydrogen-d-h-in-planetary-water-depleted-by-nuclear-fusion-technology.html
Potential Technosignature From Anomalously Low Deuterium/Hydrogen (D/H) In Planetary Water Depleted by Nuclear Fusion Technology
By Keith Cowing
Status Report
astro-ph.EP
November 28, 2024
Deuterium-deuterium (DD) fusion is viewed as an ideal energy source for humanity in the far future, given a vast seawater supply of D. Here, we consider long-lived, extraterrestrial, technological societies that develop DD fusion.
If such a society persists over geologic timescales, oceanic deuterium would diminish. For an ocean mass and initial D/H that are Earth-like, fusion power use of only ∼10 times that projected for humankind next century would deplete the deuterium-hydrogen ratio (D/H) in ∼(a few)×108 years to values below that of the local Interstellar Medium (ISM). Ocean masses of a few percent Earth’s would reach anomalously low D/H in ∼106 to 107 years. The timescale shortens with greater energy consumption, smaller oceans, or lower initial D/H.
Here, we suggest that anomalous D/H in planetary water below local ISM values of ∼16×10−6 (set by Big Bang nucleosynthesis plus deuterium loss onto dust or small admixtures of deuterium-poor stellar material) may be a technosignature. Unlike SETI from radio signals, anomalous D/H would persist for eons, even if civilizations perish or relocate.
We discuss wavelengths of strong absorption features for detecting D/H anomalies in atmospheric water vapor. These are vibrational O-D stretching at 3.7 μm in transmission spectroscopy of Earth-like worlds, ∼1.5 μm (in the wings of the 1.4 μm water band) in the shorter near-infrared for direct imaging by Habitable Worlds Observatory, and 3.7 μm or ∼7.5 μm (in the wings of the broad 6.3 μm bending vibration of water) for concepts like the Large Interferometer for Exoplanets (LIFE).
David C. Catling, Joshua Krissansen-Totton, Tyler D. Robinson
Comments: Submitted to Astrophys. J. on March 12, 2024. Accepted for publication on November 27, 2024
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2411.18595 [astro-ph.EP] (or arXiv:2411.18595v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2411.18595
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Submission history
From: David Catling
[v1] Wed, 27 Nov 2024 18:40:46 UTC (1,853 KB)
https://arxiv.org/abs/2411.18595
Astrobiology, Astrochemistry