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This would be something mass produced by a secret organization that has learned how to mass produce antimatter. Since antimatter particles colliding with the particles of its corresponding regular matter form results in them both annihilating, is it possible that shooting antimatter at someone would just vaporize them? As well as most other materials struck? And if so, is there a way to fire antimatter through the air without it annihilating as soon as it touches the air?

Basically, the end results would be energy cannons that are handheld rifles, guns on tanks and planes, and starships too, that fire orange beams that are composed of a mixture of most types of antimatter so they'd annihilate anything they hit except for what the air is composed of. A good comparison of functionality are the Tesseract-powered guns from Captain America: The First Avenger. If I wanted a series of guns that function in that way but are more powerful, would antimatter be able to accomplish that?

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    $\begingroup$ If they can mass produce anti matter, then they can contain it? probably trapping it between magnets, bullets may work in a semi fictional setting but not lasers. $\endgroup$ – user69935 Feb 29 at 17:06
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    $\begingroup$ For shooting it through the air: you need to have some kind of containment anyway and a single gram of antimatter-matter annihilation is like an atombomb going off so you dont need much. You have antimatter containment capsule that only has to hold out for seconds at most when fired. When it hits the target the capsule breaks and the air/target get hit by the antimatter. Results should be interesting. A question I've had actually: what if antimatter touches a molecule that isnt its matter-opposite? Say anti-hydrogen touching carbon? $\endgroup$ – Demigan Feb 29 at 17:07
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    $\begingroup$ @Demigan I don't think they have to be exact opposites. An antiproton of hydrogen can still hit a proton of carbon. $\endgroup$ – Zxyrra Mar 1 at 0:31
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    $\begingroup$ @Demigan: conservation of charge, quantum spin, etc... kicks in, then you draw as many Feyman diagrams (those that are highly probable) to see which annihilate into energy or other particle etc. ;D $\endgroup$ – user6760 Mar 1 at 4:37
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    $\begingroup$ @Demigan the underlying reaction is a quark-antiquark one, and as such all that matters is that an antibaryon (which may be an antiproton or an antineutron, for example) contacts a baryon, and foom. An antiproton hitting a carbon nucleus will produce a bunch of daughter pions which will interact with spectator baryons in the carbon nucleus, and probably deliver enough energy to fission it. $\endgroup$ – Starfish Prime Mar 1 at 9:52
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Antimatter particles would have limited destructive power, because of the Leidenfrost effect.

I had not thought of the Leidenfrost effect in this context but it makes good sense and is very cool.

First: the Leidenfrost effect.

https://helix.northwestern.edu/blog/2015/02/stovetop-science-exploring-leidenfrost-effectleidenfronst effect

https://en.wikipedia.org/wiki/Leidenfrost_effect

The Leidenfrost effect is a physical phenomenon in which a liquid, close to a surface that is significantly hotter than the liquid's boiling point, produces an insulating vapor layer that keeps the liquid from boiling rapidly. Because of this 'repulsive force', a droplet hovers over the surface rather than making physical contact with the hot surface.

Backyard scientist really brings this home with his video of pouring molten alumimum on a steak.

One would think that with such heat energy as is in the molten aluminum, the steak would burst into flames, or at least be cooked. But the steak stays raw - at the interaction between metal and meat, the products of that interaction prohibit a greater interaction, and so the metal slides off the steak of a cushion of steam.

Exactly this would happen with your antimatter projectile.

Matter-antimatter Cosmology: the Radiative period

When annihilating, nucleons and antinucleons produce a relatively large number of high energy photons, positrons and electrons. These particles, and having a small or zero mass, carry a large momentum. As a result they exert a strong annihilation pressure (also called Leidenfrost pressure) upon matter and antimatter brother energy also heats the medium… Because of the short annihilation mean free path, matter and antimatter penetrate each other only in the region along the boundary with the depth small compared to the emulsion typical size.

When matter and antimatter come into first contact - the atoms on the outermost edge - those atoms change into energy. As a result there is an absolutely enormous radiation pressure suddenly between antimatter and matter. It pushes them apart and also probably turns some of the adjoining unreacted particles and antiparticles into plasma. The hot plasma expands, also pushing the two surfaces apart.

The result: your antimatter projectile would produce a flash of light and bounce energetically away from whatever it hit, in large part intact. You might be distracted by the extremely bright, continuing and even more energetic matter and antimatter plasma clouds in the area where your projectile hit. These expand rapidly and react with each other, producing a spectacular light show.

You should not be distracted because the large remaining portion of your antimatter projectile has bounced energetically away from your target and is coming back in your direction. Although even if it hits you, it will probably not hurt you that badly either.


I should clarify - I was thinking strictly of space and an antimatter particle fired thru a vacuum. In an atmosphere the antimatter will react with atmosphere and produce a plasma cloud which will produce an even larger but less hot cloud of gas.


Addendum 2 - More on Leidenfrost pressure which is probably a bad name. It should be called annihilation pressure. I was worried Starfish (see comments) was right. Horrors! But I am reassured. Annihilation pressure is caused by the products of annihilation. Described here:

Gamma Ray Asgtrophysics

The basic idea of the model is the following. Along the matter-antimatter boundary, annihilation produces high energy particles: photons, electrons, and positrons. These particles together with secondary particles percent put into motion by collisions, carry their momentum to the fluid which is made of matter (or antimatter)and radiation over some distance gamma. Because as many particles generated by annihilation are going towards my has’s are going towards antimatter depression nature on both sides of the boundary is inversely proportional to the area of the effective surface where there stopped. These areas are proportional to [formula describing boundary shape] where pa is the annihilation pressure carried by the high energy particles.

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    $\begingroup$ I mean, that intense burst of radiation is going to be intense, the remaining plasmas will diffuse out and into each other (resulting in further annihilations) and if your containment system was originally made of matter then it’ll act to prevent this anyway (by exploding too). Definitely worth bearing in mind though! $\endgroup$ – Joe Bloggs Feb 29 at 18:47
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    $\begingroup$ Not to say it won’t reduce the destructive effect, mind you. Just that ‘reduced’ might not mean a whole lot in the context of ‘I just released enough energy to turn around a non-negligible mass of antimatter with nothing but radiation pressure $\endgroup$ – Joe Bloggs Feb 29 at 19:03
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    $\begingroup$ @JoeBloggs - I recommend welding goggles for this endeavor. $\endgroup$ – Willk Feb 29 at 19:29
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    $\begingroup$ @Willk Your answers never cease to surprise me. $\endgroup$ – Jedediah Mar 1 at 3:17
  • $\begingroup$ Wait, so are you saying that a gram of antimatter wouldn't go boom or produce actual devastation? Surely it would completely annihilate over some period of time, produce enormous energy which has to go somewhere... $\endgroup$ – Michael Mar 1 at 5:18
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TL;DR: this is a dangerous and wasteful way to make a gun. Probably not worth it, as almost any other kind of weapon will be better.


is it possible that shooting antimatter at someone would just vaporize them?

Well, yes. They may indeed be vapourised. The problem is that the "vapour" that results will be a cloud of very hot, very dense plasma, which will expand rapidly until it reaches equilibrium with the surrounding atmosphere. Also commonly known as an explosion. Delivering enough energy to vapourise a human body will create a very large explosion.

Whilst some people are of the opinion that there's no such thing as overkill, there is such a thing as efficiency... you can kill a person, or disable a vehicle, by poking a hole through it, which requires a lot less power than reducing them to plasma and causes a lot less collateral damage.

Speaking of collateral damage, the ultimate end result of annihilation is the production of a lot of gamma rays. These have a short free path in meat and metal, but can travel quite a long way in air. They're a serious risk to bystanders and indeed the wielder of an antimatter gun who is stupid enough to use it at short range. The annihilation flash will also be extremely, blindingly bright.

(also note that if you shoot enough antimatter, everyone and everything will be annihilated... effective yield is 43 kilotonnes of TNT equivalent per gram of antimatter. Use sparingly)

And if so, is there a way to fire antimatter through the air without it annihilating as soon as it touches the air?

You need to confine it in something... electromagnetic confinement in a Penning trap is what people try and do currently. You might be able to miniaturise the traps so that they're merely grenade or bullet sized in stead of bomb or vehicle sized. Other people have handwaved antiparticle confinement inside fullerene molecules... if this involved some kind of confinement other than electrostatic then it might work, but I can't find any serious analysis of this sort of thing so it probably won't work.

Remember that if your antimatter becomes deconfined before it hits the target, you'll end up having a really bad day. If your confinement systems run out of power, or they're badly damaged, or burnt, they'll go boom. If you're subject to highly penetrating radiation, that could give some of your antimatter enough energy to escape confinement which might then damage it enough to deconfine the rest, too. If people are throwing around antimatter weapons, then there will be a lot of gamma rays flying around, and these are indeed highly penetrating radiation.

Basically, the end results would be energy cannons... that fire orange beams that are composed of a mixture of most types of antimatter so they'd annihilate anything they hit except for what the air is composed of.

No orange beams for you, sadly. In an atmosphere, you wouldn't be able to make a pure enough vacuum over a long enough distance and maintain it for sufficient time to throw antiparticles down the middle of the beam to zap the target, and if you could you could use the beam-generation system as a weapon all by itself without all that dangerous mucking about with antimatter.

In a vacuum you could fire an antiparticle beam, but particle beams suffer from thermal blooming that strongly limit their range compared to pretty much any other weapon system. You can increase particle speed to improve range, but once you get over beam energies of about 1 GeV per nucleon you may as well just use regular matter instead (because the kinetic energy of the particle starts significantly exceeding the energy released by its annihilation).

You'd be better off putting your antimatter in a missile warhead or cannon round, or using it in your own generators or rocket engines.


Do note that there's a common canard that if you bash a blob of antimatter and a blob of matter together, they'll just blast themselves apart. This is somewhat unlikely: annihilation releases a spray of highly energetic and fairly penetrating radiation. Both blobs will be thoroughly toasted by this radiation to quite a depth, and that means they'll explode from the inside, not just at the contact point. You'll get two more-or-less spherically expanding clouds of plasma which will interpenetrate and annihilate as they expand. A small quantity of antimatter may escape in a vacuum, from the back face of the antimatter blob. There's no danger of getting hemispherically expanding clouds that won't contact; physics doesn't work that way.

You can of course trivially fix this by having the mass of the confinement and delivery system exceed the mass of the antimatter warhead, and having a decent amount of that mass being behind the warhead. For really big lumps of antimatter, break them down into smaller, separate confinement devices. There's little danger any antiparticles will escape.

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Nope.

Antimatter annihilation is 265 times more efficient than a Fusion reaction. An antimatter bullet or beam is like an H-bomb. The energy released will blow your target to bits like a regular explosive as soon as a tiny amount of matter/antimatter annihilation occurs - so you won't get the disintegration effect like you want.

You could use bio/nano tech to rapidly disassemble organic matter. Have the nanites be chemically powered (or any power source that can scale down), they get hot, chop everything to bits super fast on a tiny scale, then run out of gas and die after about a persons worth of disassembly. The heat released from the rapid movement causes the person to vaporize instead of just melting into a puddle of goo.

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As you say, antimatter interact with matter leading to reciprocal annihilation.

Because of this you have to look at all the possible interactions between your bullet and the environment.

First of all, in a traditional gun the bullet interact with the barrel by friction: this would result in a nice gamma ray burst as soon as you fire. Not a good idea if you want to destroy your target and survive.

While you can think of some sort of magnetically suspended barrel to prevent the above, you cannot do much when it comes with the interaction with air, unless you ask your target to pretty please hold a vacuum tube going from your gun to him.

So, all in all, antimatter guns might be feasible only in space.

Unless you can come up wit an exceptionally good confinement system, allowing you to contain a few grams of antimatter inside a conventional bullet. Once the bullet destroys on impact, the antimatter will annihilate. (thanks at Demigan for the hint)

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  • $\begingroup$ An entire BULLET of antimatter? Even 40K would find that excessive for a small-arms weapon. Wouldnt a vacuum pellet surrounding the antimatter and fired at the same velocity work to get it to the target before it detonates work? $\endgroup$ – Demigan Feb 29 at 17:37
  • $\begingroup$ @Demigan, good point and thanks $\endgroup$ – L.Dutch - Reinstate Monica Feb 29 at 17:41
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    $\begingroup$ "to contain a few grams of antimatter inside a conventional bullet" Good God, mate, what armor is wearing that soldier you want to kill with a few grams of antimatter? A nuclear bunker? $\endgroup$ – Adrian Colomitchi Mar 1 at 10:56
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So, oddly enough, I had a similar idea to this a while back. Now keep in mind, my version is more WMD than “personal weapon,” but you may be able to scale it down.

So, generally speaking, if your civilization can make antimatter in large enough quantities to weaponize, you probably have excellent containment that’s way beyond anything we have. Going on this assumption the weapon works fairly simply. It takes an antimatter “slug” and puts it in a stable magnetic field. We have quite a bit of research going on right now with plasmas generating their own magnetic fields that can serve to contain them, so this shouldn’t be too far fetched. The weapon then uses railgun or coil-gun action to accelerate the slug at Ridiculous Speed (Insert dramatic echo). Now, this last part may require a little more handwavium but I don’t think it’s complete sci-fi. As the slug leaves the weapon it is enveloped in a dense, cold plasma that is held in place by the magnetic field, which also keeps it from contacting the antimatter. Basically, it forms a bubble that is held in place by the magnetic field. Whenever the slug strikes a target, the bubble “pops” and then everything within a very large radius goes away. This also has the added bonus of allowing some penetration into a target before the bubble bursts, depending on the density of the surrounding plasma, the speed of the slug, and the strength of the magnetic field.


A couple important things to remember: This is a pretty far future type weapon, all the stuff that I mentioned might be possible in theory, but we don’t have anything close to this right now. Also, antimatter is volatile, seriously. An antimatter hand grenade would make a nuke look like a particularly energetic firecracker. Remember, always use appropriate amounts of antimatter, the life you save may be your own.

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I don’t think it’s realistic to use antimatter munitions against other soldiers, if only because it’s complete overkill. The energy released upon impact is comparable to that of many atomic bombs, I would think. (I’m thinking of Death’s End by Liu Cixin, in which a group of renegade soldiers threatens to take on an armada of space ships with little more than some old fashioned rifles and bullets loaded with antimatter.)

I’m also reminded of the “lasguns” in Dune which, upon striking a shield generator, result in an atomic blast that kills both the attacker and the defender. Herbert never mentioned antimatter, but maybe his invention is closer to what you’re imagining, and the sheer power of such weapons makes for an interesting plot device.

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  • $\begingroup$ Wouldnt they use extremely small amounts of antimatter instead? Why would they instantly go for atomic bomb yield bullets? And considering the total antimatter production in the world ever is nanograms (perhaps less?) Any stable production method would likely create just a few grams per day. $\endgroup$ – Demigan Mar 1 at 6:46
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If I wanted a series of guns that function in that way but are more powerful, would antimatter be able to accomplish that?

Yes. Assuming you can contain the antimatter inside a projectile that shatters on impact.

The trick is to use very small quantities of antimatter - which is rather lucky, considering the difficulty of obtaining and containing anti-matter.
E.g. half a nanogram of antimatter annihilates another half a nanogram of matter, the result is mc^2 = 1e-12kg*(3e8)^2 = 90000J. Mostly as hard gamma, but enough of it will result in very energetic particles (e.g. nucleons as fragments of a nucleus incompletely annihilated ). If 5% of this energy is adsorbed by the penetrated body, that's the equivalent of discharging a 12-gauge shotgun directly inside the body.

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You need to have encapsulated antimatter projectiles: these will effectively be super-explosive bullets with yields equivalent to tactical nuclear weapons (or less, if you want low-power weapons).
Otherwise, as others have mentioned, interaction with air will be a problem.

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