So far, my previous Black Hole Gun has seen interesting results. However, I also thought back to the Black Hole Launcher, and how to make the Black Hole itself a "projectile".

There are a special kind of Black Holes that have electric charges, Reissner-Nordstrom Black Holes, made when Black Holes absorb electric charge. If they absorb enough charge, they become stable and extremal. Charged Black Holes can also be Micro, like for my previous gun. There are some arguments that they do not exist, but that one can be tossed aside for this question. So, my assumption is that Charged, Micro and Stable Black Holes exist. They have the same variable mass as normal Micro Black Holes, anywhere between a few micrograms and trillions of kilograms (though 1 kg per Micro Black Hole seems to be the safest bet).

Macron Accelerators use electrostatic accelerators to accelerate charged particles to very high speeds. They have appeared here as a solution to Plasma Guns, the question also by me.

Now, I thought that to make the Macron Accelerator more powerful, instead of having Buckyballs laced with deuterium or antimatter, the Charged Black Holes can be the ammunition for the Macron Accelerator instead. I was picturing using electric fields to keep these Black Holes in place in the barrels, before accelerating them as projectiles when needed.

Once again, my question is about the effect. What will be the likely effect of hundreds to thousands of Micro Black Holes slamming at you at high speeds?

  • 1
    $\begingroup$ If their mass was 1 kg they would likely do nothing and pass straight through the person, not interacting with many or any atoms. $\endgroup$ Dec 2, 2020 at 4:02
  • 1
    $\begingroup$ Just to clarify a 1kg blackhole has a Schwarzschild radius of 1.5E-27. This is much smaller than subatomic particles and would have no effect on matter but its a cool idea, give them more mass and the results would be interesting. $\endgroup$ Dec 2, 2020 at 4:23
  • $\begingroup$ By how much? How heavy? Would 10 be enough? 100? $\endgroup$ Dec 2, 2020 at 4:25
  • $\begingroup$ You mentions trillions of kg in the question, this is a start with the blackholes radius being the radius of a proton but even then its hit and miss, I think you may need to add quite a few orders of magnitude and it also depends on the speed of the projectile, their gravitational effect may only affect the person after it passes through them. $\endgroup$ Dec 2, 2020 at 4:35
  • $\begingroup$ The lifetime of a 1 kg BH is 8.3E-17 seconds. It's going to go bang long before it reach the end of the barrel of your gun. See black hole calculator $\endgroup$ Feb 6, 2021 at 0:56

2 Answers 2


The problems with this are legion, but I'll try and make a start.

  1. Making your projectiles requires near-godlike levels of technology. If you can manufacture these things in bulk, you're so far post-human that what you probably won't be doing is shooting them at semi-evolved simians because they'll be about as far beneath your notice as the arthropods that live on human eyelashes are from the humans they inhabit. It is orders of magnitude harder to make a charged extremal black hole than it is to make a regular black hole (because non-extremal black holes will neutralise by injesting opposite-charged no-longer-virtual particles as they evaporate by Hawking radiation) to the point where it isn't obviously possible at all.
  2. The charge of a 1kg extremal black hole is about 3x10-10 coulombs (if I've followed this correctly), and it has a schwarzschild radius of about 1x10-27m. That's the charge of a few billion protons in a space vastly smaller than a single proton... that's a colossal charge-density, which is going to be all sorts of fun to contain and manipulate without it self-neutralising by stealing electrons of all nearby matter (or alternatively, stealing all the nuclei and turning into a tiny blob of nuclear-density matter). This neutralisation won't cause it to collapse (because the hole is too tiny for mere matter to fall into) but it will cause it to generate a lot of heat before turning into something that acts more or less like a stable neutral black hole, from the point of view of macroscopic observers.
  3. Given the projectile's self-neutralising nature, it will ultimately only interact with normal matter by crashing into it, like a dumb, boring bullet. Only it has such a tiny size and enormous density compared to any target that it can only lose a small portion of its energy in collisions before simply whizzing out the other side. Supreme armour penetration, almost no damage potential.
  4. Charged black holes big enough to ingest an electron are likely to neutralise their internal charge, meaning that the inner horizon will shrink and regular black hole evaporation will restart. The hole will then either go foom, or find a new stable smaller size (depending on the rate of mass loss vs the rate of charge neutralisation). This means that your trillion-tonne holes may not be nearly as stable as you might think, and even smaller ones might be iffy.

Given the hideous difficulties of manufacturing, storing and firing such a thing, not to mention the colossal amount of energy that would have to be invested in the manufacture of each, it seems difficult to think of a less efficient way to kill a person. Just take all those petajoules of energy and do something useful with them like making antimatter or a kugelblitz or just driving a plain old railgun instead.

(also, not gonna lie, I saw "macron cannon" and through of these. i am now disappointed)

  • $\begingroup$ Eh, isnt a kugelblitz a BH made out of energy like light or heat? $\endgroup$
    – Demigan
    Feb 5, 2021 at 21:05
  • $\begingroup$ @Demigan sure, but you can conceivably make a little black hole gun using them which would be vastly more destructive than the device the OP is thinking of, and probably orders of magnitude easier to build too. $\endgroup$ Feb 5, 2021 at 21:25

An interesting question but a lot will either need to be tweaked or hand-waved, like how could extremely high mass BH's be stored and loaded, how would they not affect anything near them, at what range will they be fired and at what speeds? The earlier mass issues and their gravitation effect will be the biggest issues and if these are hand-waved then the result on the target may as well be the most visually impressive result.

At any range if their mass is enough the target will be pulled towards them but this also would affect the shooter, unless you have ways around this. If you decide to hand-wave all the problems with this idea (as cool as it its) you could use simple physics to and all matter is drawn into individual vortexes towards each micro BH, or any BH's that are closest will have a stronger pull but as the matter draws close it will shred and warp into a rotation to the multiple BH's.

  • $\begingroup$ If its a 1kg BH, it has a 1kg gravitational pull. While you do get a spike in gravity as it gets closer you'll not be experiencing a lot. Best case scenario you have enough mass to rip a few mm of matter out of your target $\endgroup$
    – Demigan
    Feb 5, 2021 at 21:09

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .