Quasar Cannons & Black Hole Tech

Quasar Cannons & Black Hole Tech

Show Video

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 22:04

Show Video

Other news