Black holes are objects of mystery and dread from which nothing can escape… but could they also be the foundations of future civilizations of unimaginable might and size. Black holes are interesting objects that have fascinated us both in science and science fiction, but their portrayal in science fiction and even often in science has tended to be flawed and included a lot of misconceptions. We’ll be clearing those up today as we discuss technological applications we might have with black holes and seeing how they might be the centers of future civilizations – metaphorically and even physically – not their destroyers. Though we will also be examining weapons based around black holes, including the
Quasar Cannon, Obhof Gun and black hole bomb. We need to start with the key misconception though, and that’s the idea that black holes are these invisible monsters that sneak up on you and from which you can’t escape. In reality it's very difficult to get sucked into one especially before you notice it's there. Your typical black hole is the leftover remnant of a star so big that it stretched millions of miles across and would be lethal to be anywhere within hundreds of million miles of it. The kind of stars that put out tens or even hundreds of thousands of times
more light than our own sun does. And yet a black hole of, say, three solar masses, is 11 miles or 18 kilometers wide, very tiny compared to planets or even moons, let alone the star that made them, with a volume quadrillions of times higher. That monster may be tiny but it still has mass and its gravity acts normally, so that the force of gravity would be huge and stronger than Earth’s surface once you got about 4 million miles or 6 million kilometers away. Indeed this is one of our coolest features of a black hole, we could build a shellworld around it of that radius and terraform that and have an Earth-like planet with that black hole at its core that had one million times the surface area as Earth. A Mega-Earth, as we discussed in our episode of that name.
And black holes of other sizes can exist with these structures around them, and these might range from black holes even bigger than the one in our galactic center – what we call a Birch Planet, down to one’s small enough to make a modest asteroid have regular surface gravity, a micro-planet. We’ll discuss those more later but two quick notes. First, as long as you want the same gravity, the surface area of any sphere is going to be proportional to its mass. Ten times the mass, ten times the living area, a thousandth the mass, a thousandth the living area. Your density varies linearly if you do this though, and is why point-like or near point-like objects such as black holes are thought to be so handy in this regard, forming the literal center of your civilization. In the absence of them,
your shell worlds can only have Earth Like gravity at roughly Earth Radius out to the mass of a brown dwarf, which admittedly is still a very big range offering some very big artificial planets. Second, while this would be the literal center of a very big civilization if built around a natural black hole, we also mean this more metaphorically, because they are essentially the epitome of power generation. You get a high fraction of mass energy conversion from them, and you can use any fuel at all. Indeed you get better results than by fusion, but it’s also something you can do with leftover fusion byproducts like helium that don’t have a lot of chemical uses. In theory you could even use dark matter to bulk up a black hole, and get power from it, but this is a good place to discuss the difference in how you get power from a black hole, as they control how you can use one, how big of one you want to use, and what you can use it for. This
episode isn’t meant to be focused on generating power off of black holes but it’s fairly critical to other applications and technologies so we’ll go over them in modest detail. Now there’s 5 techniques but essentially they all work around two basic approaches: gather energy from things ramming into each other or heating up while falling in, and gather energy from black holes directly. That last can cause some head-scratching since a black hole is best known for nothing being able to leave it, though this is a misunderstanding. For instance, photons,
being particles of light, can’t escape from any region of the black hole where its escape velocity is equal to the speed of light or higher – the event horizon is that boundary. On the other hand, gravitons, the particle of gravity, also move along at light speed and don’t have this issue, since if they did there wouldn’t be any gravity escaping it. Now that’s a bit of over-simplification of how gravity and general relativity work but that same sort of over-simplification is how black holes get ascribed their better-known misconceptions. Right until the moment you hit that event horizon, you are not trapped, and indeed you would simply enter a normal orbit around one from which you could easily break away. The thing is, lots of other items will do this over time. And the gravity the nearer you get to it is
increasingly harsh and tidal, so that an object of any size might feel a stronger pull on the part closer to the black hole and get shredded by that. Your feet experience slightly more gravity when you’re standing than your head does, but it’s trivial. However, if gravity was ten times higher at your feet than your head you would definitely get injured badly by that tidal force difference, and black holes are even worse about this, indeed they can be so sharp in force change near their boundaries they can rip molecules or even atoms apart, and this is sharper with smaller black holes. But even without that, this accumulating cloud
of objects will tend to collide occasionally and generate a collision cascade like we consider with orbital debris around Earth in Kessler Syndrome, only far worse. This ends up being the accretion disk around the black hole and it emits radiation, which being above the event horizon can leave and can be absorbed by us for power. By dumping matter down toward a black hole, especially by having it slightly offset so it wants to orbit, not fall straight in, you’re feeding this process and emitting radiation every time there’s a collision, often at energies that would cause fusion too. And this gives us one type of black hole power generation, Accretion Disk Utilization, and a very easy one to tap, indeed easier than most modern power generation, and as we’ll see today, while reaching a black hole or creating one artificially might be technological difficult, generating power off them mostly is not. In this case, the accretion disk of a black hole, consisting of material spiraling into it, heats up due to friction and gravitational forces, emitting radiation. Keep in mind that hot gas around 6000 kelvin is what gives us sunlight, so it’s not hard to tap, though most accretion disk radiation is going to be vastly hotter, tending to X-rays or Gamma-Rays. This radiation could potentially
be used as an energy source, though as it would be in dangerous spectrums, you would either want to surround it with more gas to absorb and emit cooler wavelengths, much as the gas around our sun’s fusing core does, or wrap it in something like a big lead or Tungsten shell. Something that can absorb gamma and get hot, and then you can run a heat engine or a thermocouple off of it. A ship in a higher orbit around a black hole would probably want to extend a large thin sail perpendicular to the pull of the black hole to gain power this way. And there’s no need for total enclosure of the black hole, any more than hanging a solar panel over the Sun, you just might keep scaling up till you got to that point. There’s nothing low-powered about this method but it’s not your highest efficiency path either. It’s simple and controllable. And often you would use
this method in tandem with others – and for that matter the power harnessing aspect is often going to be similar, which is to say, absorb high-energy radiation and convert it into electricity. We use this same approach with Magnetic Field Exploitation. Black Holes spin incredibly fast, and generate insanely powerful magnetic fields assuming they have charge. So Black holes with strong magnetic fields, particularly those around some supermassive black holes, could theoretically be used to generate power. Similarly, ionized Gas and dust spiraling into
the black hole from that magnetic field at high speeds can heat up and emit intense radiation, which could potentially be harnessed. Again we’re fundamentally talking about either a dynamo or perhaps a stream of ionized particles flowing down into that monster and power production isn’t too difficult to explain as a concept. The Penrose Process is conceptually less simple though a bit parallel, and since we’re not going to touch on general relativity or frame-dragging today beyond the basics, it can be summarized as stealing spin energy from a black hole. Proposed by Roger Penrose in the 1960s, this method involves extracting energy from the rotational energy of a rotating black hole. Black holes usually have a large
percentage of their total energy as rotational energy, often around 20%, and this rotation, to put it in simple terms, gives you a region around the black hole just outside the event horizon that’s wider at the spinning equator than the polar region. We call this the ergosphere. The idea is to drop an object into the black hole's ergosphere, the region outside the event horizon where objects cannot remain in place. The object would split into two, with one part falling into the black hole and the other escaping at a higher energy level than the original, thus extracting energy from the black hole. Ergo means ‘work’, and the erg is the lesser-known unit
of energy beside the joule, and this name was chosen because you can dip things into it to extract work from it, in a process that slows the black hole's rotation just a little bit. Generally, that’s a good thing, as for other applications a non-spinning or slow-spinning black hole is easier to work with, but if you wanted to you could always do controlled drops of matter to add more angular momentum. Akin to this would be wrapping a black hole in mirrors at a distance and sending beams down through the ergosphere, where they can get amplified during passage by stealing some of that rotational energy. This is basically how a black hole bomb works which will touch on more later. Our next one is Blandford-Znajek Process,
or BZ Process, which is another method of getting at that buried rotational energy in a black hole using similar physics to our last two and tapping that ergosphere. The black hole’s magnetic field lines passing through the ergosphere become twisted due to the black hole's rotation. This twisting is due to frame-dragging, where the rotation of the black hole drags space-time around with it, but again we’re not going to dip into that in depth today. Extraction of Rotational Energy is achieved as the magnetic field lines twist, they can tap into the rotational energy of the black hole. This energy is then transferred along the magnetic field lines away from the black hole. Which essentially means it spits out high-energy particles and radiation, and you capture those. The same will be true of our fifth process,
Hawking radiation, which we’ll get to in a moment, but again the theme is that you send matter down into the black hole and extract a percentage of its energy in the process, usually a fraction of what you dropped in there in terms of mass energy but getting 20% of your mass energy back is pretty good, given that stars usually convert much less than 1%, and take very long times to do it. Now the BZ Process is how we think quasars get their energy and these are objects so bright they outshine entire galaxies and by a heavy margin. It’s a leading suspect for the process behind gamma-ray bursts and importantly it is not omni-directional, it blows out the poles in a bit of beam. We don’t know for sure if this is the mechanism for any of them, but it is considered
to be the most plausible explanation for the immense energy output observed in quasars and other active galactic nuclei. These are some of the most luminous and energetic objects in the universe, and it's believed that they are powered by accreting supermassive black holes. We know what’s happening but aren’t sure of the mechanism, alternatively for our fifth and final one, Hawking Radiation, we understand the process very well but have essentially no way to confirm it. This method is named after Stephen Hawking and is, incidentally, what he’s originally famous in physics circles for before he got famous with everyone else, along with him and Penrose’s work on black holes in general. Our inability to get experimental proof of Hawking radiation is why he never got the Nobel Prize, but the math and reasoning fits so perfectly that it tends to be taken for granted that it's correct, same as we don’t have experimental proof of what's in the Sun’s core or Earth’s for that matter. It’s also appropriate for our last type to discuss as it is not expected to naturally occur in any significant quantities for quintillions of years after the last star burns out. As a quick caveat, I say ‘last’ but that’s
not including some stranger or more obscure singularity methods allowed under various theories and cosmologies. If you start throwing in string theory, naked singularities, wormholes, or extra dimensions, other options can arise. We’ve done entire episodes on explaining Hawking Radiation and from different angles of attack, and we’ll be examining the method more in a month, so we’ll summarize here. All of space and time is constantly frothing with new virtual particles popping in and out of existence – see our episode on Vacuum Energy & Zero Point Energy for discussion of those mechanisms. Normally this is as two opposite particles that almost
inevitably run into each other and annihilate. Indeed, it’s been suggested that it's really the same particle moving forward than backward for a tiny instant of time, since a particle moving backward in time looks and acts identical to its antimatter twin in this interaction. The black hole itself is not generating this energy, rather it’s the extreme tidal force. Two particles pop
up near an event horizon, as they do everywhere else all of the time, but here one of them is just a bit closer to it and experiences a bit more gravity, and gets pulled in while its partner does not. It flies off, un-annihilated, and we absorb it for power just like any other radiation. Now the problem is that even a black hole doesn’t have that much tidal difference nears its surface, it might be so immense that as you fall into it feet first your feet are experiencing millions of g’s more force than your head and you get shredded down to you atoms, spaghettified as it’s called, but the math tells us this should still be very rare. So rare that even a single electron-positron pair having this break happen on a 3 Solar Mass black hole’s event horizon should occur only a few times in a billion years. Alternatively, the tidal forces on a black hole a thousandth that mass are so high that even though that event horizon is a thousandth the diameter and millionth the surface area, it will kick particles out a trillion times faster per unit of area and at a total rate million times more than its big brother. It is not that the smaller one is somehow making more virtual particles, we expect this rate to be the same everywhere in the universe, including inside you or I, it’s that it’s much better at tearing them apart to make one become real and permanent and the other to fall into the black hole and reduce its mass… the two have net zero energy so the escaping one has to have positive energy while the other must then be negative. These are ‘virtual’
particles so it is fair to think of them unreal if you like, though ‘real’ is a pretty ambiguous and head-ache causing concept in theoretical physics. In any event, this means the smaller a black hole is, the faster it loses mass. Natural black holes are utterly useless for generating power off of by Hawking Radiation and will be for next trillion-trillion-trillion-trillion-trillion years, when the smallest natural black holes created by supernovae or dead star mergers will finally have trimmed down enough to be emitting enough power to run a light bulb. The bigger ones will take even longer. Now somewhere around the trillion-trillion-trillion year mark, they
would be generating enough power we could actually measure it with modern lab equipment and for that reason you might be able to run post-biological civilizations on them at that point as we examined way back in our civilizations at the end of time series in its first episode, black hole farming. But Hawking Radiation Black Holes don’t get interesting to us till they at least hit the one watt range. Which they do at 1.89 x 10^16 kilograms, or just under 2000 gigatons, the mass of a modest asteroid and about double the mass of the larger Martian Moon, Phobos. And it would keep emitting that one watt, slowly rising with time, for around 10 Trillion-Trillion years, a lot longer than the time in which stars will exist. A 10 watt black hole, which is parallel
to the power requirements of a human brain, would live 313 billion-trillion years and mass just 6 gigatons. Every time you raise the power output by a factor of a hundred, lower the mass by a factor of 10 and lifetime by a factor of a thousand. If you can make a black hole that’s less massive than these, you’ve got yourself a serious power plant, and the very nice spots are options like a gigawatt, which masses just 5.97 x 10^11 kilograms, 597 megatons or less than a single kilometer wide asteroid, or its mass equivalent in hydrogen, and would keep pumping this power out for 313 billion years, as long as all but the most long-lived of stars. This only keeps rising, and those in the 100 kiloton to one megaton range start looking like awesome spaceship drives, or power plants for entire civilizations. As a reminder though, while a 1 megaton black hole would live 1500 years, and easily power our whole modern civilization, a 100 kiloton black hole would live just a year and half, and growing steadily brighter, so is probably something you would only use on a spaceship as a booster to get up to speed for an interstellar journey.
My friend Bob Fowler worked out a nice chart of all the interesting sizes that I’ve got up on the screen that I recently started using a personal cheat sheet, and Viktor Toth’s Hawking Radiation Calculator is available online for anyone wanting to look up values on their own. They are kind of safe as they can’t be made to explode unexpectedly – unlike antimatter – but they all presumably do explode in the end as they get so low in mass. They’d make interesting weapons since they would carry huge amounts of energy in the space of something smaller than an atomic nucleus, but we looked at that more in weaponizing black holes.
I also have to admit that I am more than a bit skeptical of any black hole functioning like this under the subatomic size scale. We have no proper theory of quantum gravity, which really matters at this scale, and we have some heavy disagreement in theory versus experimental data about how much energy is sitting around in a given chunk of space in the quantum foam or if it could reach or exceed a Planck Temperature – 10^32 Kelvin, and all of these objects radiate like a black body of a given temperature, which indeed is essentially the alternative conceptual approach over virtual particles. We do have a possibility that black holes were formed in the Big Bang and which would not need to be of stellar mass, they’d have a minimum lifetime of 13.8 billion years then since they would have otherwise expired by now,
thus would have to be at least 200 megatons, though since even these would still be bright enough to radiate 8 gigawatts of power it would seem likely they were either pretty rare or more massive than that, otherwise we should be able to detect them. They also would be able to absorb more mass and energy from the area around them which changes lifetime profiles a bit too. But there could be some natural sources for black holes in a useful mass for Hawking Radiation, and ‘useful’ varies. If your goal is power a personal space habitat with around a square mile or kilometer of internal living area, then anything in the gigawatt range works perfectly, and you could do with a lot less, or simply several of them supplying power instead of one. To wrap up on Hawking Radiation black holes though, they’re essentially not useful unless you can make them and even options like kugelblitz creation – which is focusing huge amounts of photons into one place and moment – get rather iffy. Bigger is easier,
and avoids feeding problems too. No black hole useful for Hawking Radiation is bigger than an atomic nuclei which makes stuffing matter into them rather tricky. Again black holes aren’t magic vacuum cleaners and one of these would fly right through our planet without absorbing anything, being slowed by anything, or damaging anything except by radiation. That’s quite a smorgasbord
to bypass, so trying to carefully feed a matter stream in as fuel is even harder. Can we make a black hole? Yes, absolutely, unless we’re just flat out wrong about their physics. Can we make one smaller than stellar mass? Probably, and probably a lot smaller. But my own hunch is that a hawking radiation scale one, especially the sub-megaton power leviathans, is a much harder lift and maybe impossible. There’s a lot of ways you might do this. Shooting two massive iron balls or skinny rods at each other out of huge relativistic accelerators to slam into each other is probably the simplest and basically equivalent to how we did the old basic gun-style nuclear devices, though scaled up. And by that same reasoning, the trick of using explosives to implode a device that we use for other nukes would be a good approach. You surround a big
sphere of iron with nukes all set to detonate in the same instant and this implosion is basically replicating the effect inside a supernova. The kugelblitz approach of pouring energy beams into one spot all at the same time works too, its just that you probably need to be at a bigger scale. Black holes, in terms of that critical event horizon, grow much less dense as they get more massive or bigger. Ten times the mass, one hundred times less density, and that density – or the density of stuff right next to it as you try to cram it into form – is the bottleneck for making one. You need to beat a supernova. I expect this can be done and at many orders of magnitude less for the total mass, but how much less is probably impossible to say right now. Or a very good topic for a paper or thesis, so long as it is by someone other than me, Einstein Field equations make my head hurt. In any event, I think it does open the door
to larger but sub-stellar artificial black holes being a thing in the future. Which opens a lot of doors for us too. If you can make one that you can then feed up bigger on hydrogen and helium, then you can stop feeding it when it gets to your preferred mass. Or slow the feeding to keep it there if there was any significant Hawking Radiation leakage. Or you might keep feeding it to generate power, and as quick note, if you just want to add mass, you aim your beam right on target, you try to miss by a hair for power generation. In terms of why you might want
to do this, if you manufacture black holes, by dumping mass in, then generating power slows how fast you can make them since you need to otherwise dissipate that energy as fast as you make it which again is a small but decent fraction of that thing’s total mass energy. And again we’ll be looking more at Kugelblitz Black Holes next month. Beyond the power implications it's your gold-standard for decent gravity when terraforming as an alternative to spin-gravity. You can pop
a micro-black hole into the center of some asteroid and call it home, indeed an artificial gravity generator on an asteroid was the situation in the short story, Collision Orbit by Jack Williamson, that coined the term terraforming. As we’ve already discussed black holes are not monstrous planet eaters – with the exception of the Obhof Gun which we’ll get to later - and you could keep one inside a sturdy metal shell, contained by magnets to keep it from drifting – you can move a black hole with magnets too, obviously touching one with anything made of matter is not a great plan. That shell has to be able to handle the pressure of whatever mass is sitting on top of fit and now experiencing higher gravity but normal earth gravity dragging a hundred meters of asteroid regolith down is not hard to engineer around. For bigger cases, like trying to give Mars or the Moon Earth-like gravity – you would need to use active support, orbital rings or atlas pillars – see the Megastructure Compendium for details on how those work but they do take power and conveniently you have a handy power supply right there. Incidentally, no, that would not make the Moon or Mars the same Mass as Earth, it scales with surface area, so Mars would need about 38% of Earth’s mass for Earth-like gravity, and the Moon 7.4%, and in both cases minus they’re existing mass. The cool thing is that it can be any available matter, so hydrogen or helium from Jupiter would work.
We discussed this in more detail in the episode Moon: Mega City, but one parallel tech we discussed there was using lots of smaller black holes in something like 2D hexagonal layout, again anchored magnetically, to create a flat surface with gravity. I can’t ever imagine using this on a spaceship, but for space stations, or even for an inhabited spaceport on a smaller body, where you just wanted higher gravity in that area, it is an option. In theory you can expand this flat plane trick in scale to create something like a stasis field or slow time region, as black holes do slow time but only the truly enormous ones do so to any useful degree in a way that wouldn’t utterly shred anything bigger than a particle left inside it. Two even and
flat planes could allow a uniform region inside. I don’t view black holes as particularly useful for their time-distortion effects though, any more than their potential usage as a heat dump to get around some cooling issues mega-civilization have. Breaking thermodynamics with a black hole is dubious, we don’t understand the physics of that well enough to say no for sure but that’s basically the situation, we don’t think so but can’t utterly rule it out. Same for hiding your civilization by dumping your waste heat into a black hole, even if you could get 99% of your waste heat down into the thing, that’s not making you invisible, just dimmer, visible to the same instruments at a tenth the previous distance. As usual for Fermi Paradox scenarios, since you presumably only hide from bigger and older civilizations who could plausibly threaten you, you are trying to hide from someone who already knows you exist and knows the trick you’re trying to use. Plus, fundamentally, these objects are not stealthy even when truly dark because they generate tons of gravity, and more importantly, they represent some of the most valuable real estate in all the cosmos so it’s not exactly a good hiding place as everyone should want to visit it all of the time, and use it to power their civilizations. It’s like hiding your empire in a fertile river delta.
You can absolutely use a natural black hole as a power supply by those other 4 methods we discussed earlier. You can use them as gravitational slingshots, especially in pairs, to speed ships up to a decent fraction of light speed or slow them down too. This means they can be hubs for interstellar travel at a galactic scale. But there’s only around 100 million of them in this galaxy, possibly much less from mergers and ejections, which means each would be servicing a region of space on an order of 10,000 star systems, even assuming they were evenly distributed galaxy wide which they are not likely to be.
Black holes are probably ejected at high speed from the galaxy a lot and incidentally even stellar sized ones make good intergalactic spaceships, and we explored some of those starship drives, the kind used for moving actual stars, in our episode Fleet of Stars. In this way you can dump matter into them as fuel and propellant and push them toward a new galaxy to colonize and use them to sustain you till you arrive, and tow other stars with you too if you want. But they also would make for some awesome galactic sector hubs. And as we’ve discussed before,
if you’re using them to help add or subtract a ton of speed beyond what your other spaceship drives allow, they’re likely to be where the first colony ship for a given piece of the galaxy arrives. So they are in a position to become a de facto first settlement and sector capital. And thousands of star systems is quite the interstellar empire and a plausible one to maintain. That’s likely to be no more than a century or two of light lag for communication and that at least puts a unified civilization on the table as believable. Especially since that black hole represents a massive asset, no pun intended, and that system would be in a good position to keep its neighbors in its proverbial orbit. Given that it could build a spherical shell with
more living area than a Dyson Swarm, and possibly with multiple levels, it definitely has the population density aspect suitable for a galactic metropolis or capital. For a true galactic capital, or a place to collapse a galaxy into so as to avoid light lag, we have Birch planets, the bigger version of these that might being millions to even hundreds of billions of solar masses, and which one of these days I need to give its own episode, but let’s stick to assuming natural black holes in the ‘small’ stellar mass range or at most intermediate hundreds to thousands of stellar masses range for today. Black holes at this scale can be used as power supplies, the centers of shell worlds or huge habitation rings, and industrial titans, including possibly the ability to take matter streams and send them in like a supercollider to make heavier elements out of hydrogen or helium. I think a lot of these might be
possible on paper and harder or even impossible in real engineering but they will represent huge strategic and logistical advantages, and if they were the first place settled in a region, likely a historical and traditional ones too. But they also represent huge weapon platforms. You’ve probably heard of the black hole bomb, and you can get more details on that in the video by Kurzegesagt that introduced it but the key aspect is superradiant scattering. You put mirrors up around the black hole and start bouncing light beams through that ergosphere, and they pick up energy every time they go through. Since we do not have any materials able to reflect gamma rays, that’s as far as this amplification can go, but I can see this being used as both a power supply and a beam enhancement method. Obviously blowing up your black hole, or rather the area around it, is not something you want to do and would not be something done by simple sabotage, so this specific approach, if you had gamma reflective mirrors, would probably be limited to a deadman switch. If you invade us and win too well we’ll set this off…
which I can see being used as a strategy in truly ancient post-stellar civilizations to discourage attempts to steal their resources in an era where there is none left to find anywhere else. We shouldn’t rule out gamma reflective mirrors being possible, and their existence would make any number of technologies, including artificial black hole creation and usage, way easier. The same applies for anything that lets us reflect or contain dark matter, and that’s your ideal feedstock for black holes if you manipulate it since it has no other interactions but gravity and no obvious purpose but producing it. However, it won’t fall into black holes as easily as it
doesn’t interact with other matter and won’t slam into other things in an accretion disk. But getting back to dominating an interstellar empire, your big weapon you can do and which makes a natural black hole a military powerhouse is the quasar cannon. This thing makes the death star or a Nicoll-Dyson Beam look weak and I don’t think you’d ever use a full powered version on a black hole that was your civilization center. You are setting off an artificial quasar,
at some scale or another, and these emerge along poles so you can aim it like a cannon and also probably focus that beam further with magnets. You might use this as a very powerful pushing beam to accelerate immense ships to ultra-relativistic speeds. Used in a strictly weaponized form, this is an apocalyptic device that you could use for taking out whole galaxies. The Obhof Gun is a particular variation of this and actually the inspiration for the Quasar Cannon and the short video I did on it last year. A friend of mine, Larry Obhof, had inquired about planets getting eaten by black holes and it got my brain chugging along on the concept and initially I was thinking of this one graphic I often use where it show a planet falling into some huge black hole – in practice black holes are much smaller than planets, except the really big ones at galactic cores, and the Obhof Gun in my head is the scenario where you’re feeding planets into one of these monsters like shotgun shells. Each blast coming out is somewhere on an order of 10^41 joules to thousands of times that for big gas giants, and that’s a directed supernova coming out of your metaphorical shotgun. Even the low yield version is pumping out a
billion times the energy needed to vaporize Earth. I’m not sure what you would aim that weapon at, Cthulhu’s big brother maybe, and it’s the power range of gamma ray bursts and quasar bursts so it is something that naturally occurs… and of course there might be civilizations out there needing to build these things too. The extreme version of this would be chucking in not planets but white dwarfs or neutron stars, which are far more massive and compact and might make better bullets.
As terrifying a weapon as that sounds, it is fundamentally a big energy blast, so you might be using it power something or move something – like a galaxy – and I don’t know what sort of thing might be needed for drilling into other dimensions or alternate universes if they exist, or firing up new big bangs to make pocket universes, but this might be the kind of scale of device needed, something able to machinegun out hypernova blasts. And that’s a good one to end on for today, because for all the talk about power and destruction, we have seen a lot of constructive and creative uses of black holes in our discussion. And yet, one of their most popular applications in theoretical discussion is the possibility of creating new Universes, with some theories suggesting a new big bang is set off in some unreachable place every time a black hole forms. It might be
that black holes aren't made in order to create great civilizations here, but to create whole new universes somewhere else. But as I said at the beginning, for all that they're seen as the embodiment of ruin and destruction, and can indeed be unleashed to that end, the true value of black holes is to empower civilizations and function as engines of creation. We discussed some very big megastructures today that we might be able to build with certain advanced technologies, but there’s one megastructure that’s among the very largest that could be built with simple modern materials and technology, called the Topopolis, a rotating habitat that’s no wider than an O’Neill Cylinder but can be any length you desire. In this month’s Nebula Exclusive Topopolis: The Eternal River, we explored these
megastructures whose interior landscape might stretch out like some enormous river valley the entire distance of thousands or even millions of miles. Join us in journey down a river so long it traces out a thousand worlds as we explore a megastructure buildable with known science and materials but of unbelievable proportions. And again, that’s out now exclusively on Nebula, our streaming service, where you can also see every regular episode of SFIA a few days early and ad free, as well as our other bonus content, including extended editions of many episodes, and more Nebula Exclusives like last month’s look at Giant Space Monsters, December’s episode The Fermi Paradox: Hermit Shoplifter Hypothesis, Ultra-Relativistic Spaceships, Dark Stars at the Beginning of Time, Life As An Asteroid Miner, Nomadic Miners on the Moon, Space Freighters, Retrocausality, Orch Or & Free Will, Colonizing Binary Stars, and more. Nebula has tons of great content from an ever-growing community of creators. Using my link and discount it’s available now for just over $2.50 a month, less than the price of the drink or snack you might have been enjoying during the episode. When you sign up at my
link, https://go.nebula.tv/isaacarthur and use my code, isaacarthur, you not only get access to all of the great stuff Nebula offers, like Topopolis: The Eternal River, you’ll also be directly supporting this show. Again, to see SFIA early, ad free, and with all the exclusive bonus content, go to https://go.nebula.tv/isaacarthur As we explored today, with artificial gravity
provided by a black hole we could potentially settle planets which were much smaller than Earth, and that would include our own Moon, but you might not need that technology to terraform our moon. Next week, on February 22nd we’ll ask if it is possible to terraform the moon to have green lands, blues seas, and white clouds, just like Earth, and then visit the topic of Vacuum Trains and other hyperfast transit systems on Sunday February 25th, before finishing the month on February 29th, as we leap into the topic of life on colony ark ship carrying people to new worlds that will carry us ahead into this leap year and into March, where we’ll head back to the dawn of time for a look at Primordial Planets. If you’d like to get alerts when those and other episodes come out, make sure to hit the like, subscribe, and notification buttons. You can also help support the show on Patreon, and if you’d like to donate or help in other ways, you can see those options by visiting our website, IsaacArthur.net. You can also catch all of SFIA’s episodes early and ad free on our streaming service, Nebula, along with hours of bonus content like Topopolis: The Eternal River, at go.nebula.tv/isaacarthur.
As always, thanks for watching, and have a Great Week!
2024-02-20