A weapon that can instantly kill millions without harming the bodies

Question

I have a world set in the far future, no specific time for vagueness sake, that is completely war-torn by 2 warring factions. This planet is both sides' last stand, so it's all-out, no-limits warfare. Is there something that could potentially be use on the battlefield that would be noticeable, kill everyone instantly, but cause no bodily damage from the weapon itself? So no open wounds, burns, or the like. Exactly like they just dropped dead.

Answer 1

If you had some way of efficiently generating neutral particle radiation without generating a whole load of gamma rays at the same time, you could make a neutron bomb that actually worked like people seem to imagine they do ("kills people but leaves buildings standing") rather than being a nuclear weapon optimized for use on heavily armored targets like tanks.

The problem would be generating an intense enough neutron flux that it could reliably and quickly kill people (presumably even people quite well protected) without causing major tissue damage or setting things on fire. It might be possible to do this if you could make miniature deuterium-tritium fusion bombs (pure fusion weapons are already a bit neutron-bomb-like). Detonating a tiny nuke is left as an exercise to the reader, but it might be possible to do with picogram amounts of antimatter and maybe a tiny amount of some kind of fissile like uranium or plutonium. The warheads would need to be carefully engineered to maximize useful neutron flux... possibly they're encased in a layer of beryllium and/or depleted uraniumthat can act as a neutron multiplier. Materials that can convert alpha particles from the fusion reaction into more neutrons would be useful too if you can find something suitable (maybe uranium nitrides or oxides). Fast fission of U-238 might add too much thermal energy and risk cooking things. Other more exotic materials like gold might allow increased gamma ray output, but that too risks cooking things or developing a fireball with all the resultant blast damage that implies. X-ray transparent materials (like beryllium) on the top, and x-ray reflective materials (like uranium) underneath might be a good arrangement, but I Am Not A Nuclear Weapon Engineer so I can't give useful advice here ;-)

The warheads are delivered across a wide area from something a little like a cluster bomb, but each one is attached to a "smart" guidance and propulsion system to allow controlled descents so that they can perfectly synchronize their spacing and altitude and detonation times... they all need to go off at once, because the radiation flux will cause any remaining devices to fail or detonate at the wrong altitude, and you want all devices to go off at an optimum height above the terrain to maximize neutron and gamma radiation flux but minimize thermal and blast effects.

Now, if this does work, then you can deliver a dose of radiation across the battlefield in one giant pulse that should immediately incapacitate everyone. I say incapacitate because instant death might require a flux so high that you'd probably burn and blast things to bits, but a high enough dose will simply scramble the brains of victims who will fall over trying to work out what just happened and why their muscles don't work properly anymore and then quietly die where they lay a few minutes later.

Answer 2

Massive carbon dioxide flood

This would work like a limnic eruption such as killed nearly two thousand people at Lake Nyos, and also many animals. People suffocated, and it was noted at the time that it looked like a neutron bomb attack.

Answer 3

Kill Switch

In the distant future, the Facebook Pepsi Corporation covers five eights of the planet.

Every child is fitted with a Facebook Pepsi "Hornet" implant at the base of their spine to allow them wirelessly access the Metaverse, and also remotely enjoy the silky smooth taste of Pepsi Brand Cola.

The implant receives a wireless signal and transmits it to the brain as sensory data. It also broadcasts brain functions back to the Mothership.

For data protection reasons the implant has access to all of the body's critical systems. This is all contained in the GDPR legislation article 89 Subsection 3b.

One bonus feature is that shutting down the implant also shuts down all brain function. The shutdown can be done wirelessly if you have the access code. There's your weapon.

Answer 4

This kind of weapon exists and is called a nerve agent. A famous example is sarin, which was twice used in terrorist attacks in Japan. From the wiki:

Exposure is lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered.

Sarin is generally considered a weapon of mass destruction. Production and stockpiling of sarin was outlawed as of April 1997 by the Chemical Weapons Convention of 1993, and it is classified as a Schedule 1 substance.

Answer 5

Nanobot swarm

Nanobots are highly advanced nanotechnology used in warfare. They are released in swarms (which covers the criteria to be noticeable). They can be controlled and they are able to target humans. They are small enough to enter the internal systems of humans. They can stop a vital function, or block some vital blood flow, or release some deadly substance that can kill humans quickly with no significant visible bodily harm.

Answer 6

Don't say.

The war people were working on something. They must have found something. Because everyone is dead. Like they just sat down and died. Even in the tanks and war machines; even in the hazmat suits and the bunkers. But the birds are not dead. Squirrels run in the trees. Leaves stretch to the sun. Just the people are dead.

And some unusual things. Some of the bodies lie in circles, or stars. Have these dead people been arranged in patterns after they died? Did they arrange themselves then die? There are some among the dead who do not look like soldiers and do not look like locals. Where did these people come from? Why are there so many children? The birds are singing and the trees rustle in the wind, and it sounds like someone is whispering. But no-one is whispering. Everyone is dead. What was that they said?

It is the difference between porno and romance. In a porno you are shown everything. In a romance you have to wonder, and guess. Make it scary. Make them wonder.

Answer 7

Halt all brain synapse for a bit (Brain EMP)

Imagine a sustained EMP, but rather than targeting wired electronics, it's geared specifically to overload the electrics within our brain. Hold the brain in stasis for say... 4 minutes (or some other appropriate amount of time), and everyone's stopped breathing for that amount of time, their hearts and other bio functions may have also been paused for that long. By the time the brain is free to move electricity around as it normally would again, it's dead.

Answer 8

Supervillain

First, the hapless population of the planet was passivated and caused to accept the idea of a supervillain surrounding them with broadcasting satellites. The satellites released a tunable monochromatic terahertz signal, which we'll henceforth call "5G".

When the 5G was set to the right frequency, it was able to resonate the structure of oxyhemoglobin in the blood. Loosely, hemoglobin in the human body works like a Daoist sexual practice, keeping Fe2+ (ferrous ion) always just on the verge of a conclusive reaction with O2, but never quite allowing it to be satisfied. By nudging it with an intense broadcast of just the right frequency of weak non-ionizing radiation, the supervillain found a way to bring it through to the state where the oxygen reacts, leaving an inactive methemoglobin behind. Now, the body will normally restore the original hemoglobin form over time, but people all over the world were abruptly and heavily radiated with this killer 5G, which nobody had ever really studied health effects for Hz by Hz in any rigorous way (except in classified sources).

For a few minutes, each person targeted had to make do without oxygen in their blood. After that, they continued to make do without oxygen. It did not take long for the 5G system to run through the whole planet, assisted by the users' own spy devices and finishing off with satellite reconaissance.

• I should note I don't know any such frequency exists, and also the current satellites stop around 50 GHz because of water absorption in the atmosphere I think. This hardly seems enough to get in the way of a fair plan to destroy the world, let alone a sci-fi yarn.

Answer 9

The Ice-nine Approach

Vonnegut's Cat's Cradle uses as its primary macguffin Ice-nine, an allotrope of water that is solid at higher temperatures than more common ice and self-catalyzes crystallization of liquid water to its form. This is consistent with a lower-energy form of ice existing; and although thankfully no such form has yet been found, it is not excluded.

For your purposes, Ice-nine is has some flaws. First off, while one can imagine freezing a human at room temperature by this catalysis, that would be an (unusual) mark; and human-to-human contagion would require ice crystals of one to come in contact with fluids of the other, which isn't straightforward.

Instead, the same mechanism of proposing a lower-energy allotrope can be applied to the oxygen in the air itself. We don't know too much about red oxygen (O8) currently, but we're pretty confident that it's not stable at atmospheric temperatures and pressures, let alone energetically preferred to normal gaseous oxygen under those conditions. But what if...

O16 if a fifth stable allotrope of oxygen, after diatomic oxygen, ozone, oxozone, and red oxygen. It is a murky brown-to-red liquid at temperatures up to 50 deg C and pressures down to a quarter of an atmosphere. It is lower energy than diatomic oxygen under normal conditions, but does not commonly form in nature. In addition, it is only autocatalyzing on the bulk surface -- that is, a droplet of O16 will tend to arrange O2 molecules that hit its surface into new O16 molecules, eight at a time; but a handful of O16 molecules insufficient to form a drop with a well-defined surface will not cause more O16 to form. Finally, O16 is extremely sensitive to ultraviolet radiation, and decays to a mixture of O2 and O3 even in faint UV. (The ozone itself further decays to O2 with UV, but not as rapidly.)

The war between SideA and SideB reached the point where drastic measures were needed. SideA had synthesized O16 and confirmed its properties. Hundreds and thousands of liters were synthesized, and loaded into aircraft. At noon over the coastal airbases of SideA -- just as the sun finished setting over the other hemisphere, where SideB plotted their own plots -- a flight of three hundred bombers lifted off, with just enough fuel to cross the ocean. The bomb bays were empty. One fuel tank, in the fuselage, contained fuel. The other fuel tanks were filled with O16.

As the bombers crossed over into the dark hemisphere, the dump valves on the fuel tanks were opened. Falling through the atmosphere, the streams of red O16 broke up into an orange pink mist. The droplets, held together by surface tension against the wind of their own falling, did not dissipate further -- instead, they began to grow as O2 out of the rapidly thickening atmosphere adsorbed onto each drop, becoming O16 and adsorbing yet more O2.

Underneath the bombers, a flood of O16 poured onto the ground, a rainstorm of such intensity as has never been seen. And as each new droplet fell into the pooling murk below, more and more oxygen fell out of the air.

The airfall itself, although intense was, in the end, just a storm. Individual drops were small and hung in the air, causing an intense deluge over hours, rather than a literal river falling from the sky. And the watershed below was just as capable of channeling O16 as water -- with occasional dramatic landslides, dam breakages, etc.; but on the scale of a millennial hurricane, not an unimaginable disaster.

But after the fall... death. Rapid and inevitable not just for humans, but for all terrestrial animals. For the O2 level had reached so low that there was nothing to breath. Without a rise in CO2 levels the human body does not realize that it is low on oxygen -- instead, consciousness just fades, and death follows. In the lakes and the seas, the fish survive, as the dissolved oxygen cannot adsorb onto the O16 that is mixing in with the water rather than forming drops.

The sun rises the next morning over a flooded, brown, desolate landscape. With the first rays of the sun a mist is seen shimmering over all the lands. The O16 is breaking back down to O2, which is remixing with the air. Sporadic forest fires start as local oxygen concentrations spike; and with no one to put them out, some grow out of control. But in the cities, where there was nothing to burn; in the valleys, where the O16 flowed to the sea and will burn off from the surface over the next few days; and where the fires did not, by chance, start -- all that is left is the blue-lipped corpses of all that once was alive.

Answer 10

Vacuum bomb

Those near the ignition point are obliterated. Those at the fringe are likely to suffer many internal, thus invisible injuries, including burst eardrums and crushed inner ear organs, severe concussions, ruptured lungs and internal organs, and possibly blindness."

Just be aware this is a good way to get on human rights groups naughty list.

Answer 11

Anti-gravity satellites

Special device (or weapon) emitting a gravity beam to pick up people from the surface and put them in a low orbit trajectory, long enough to kill them. Most times they need to be put up say 10km in the air.. keep them up there for a few minutes, they will just suffocate and freeze a bit. In the air, you can do with them whatever you like. You can also put their corpses back on the surface again, gently. They will unfreeze and their bodies sustained little damage, except the brain damage that killed them.

Answer 12

If the goal is just to leave intact corpses, then there are a lot of options – poison gas, plague, radiation – but they are all far from "clean". Any chemical or biological agent is virtually impossible to disperse over a significant area such that everyone gets a promptly lethal dose; realistically, if you sprayed an oil tanker's worth of VX on Chicago, some people would get a million doses and die in minutes, but some would be running around panicking hours later, and some would still be alive after a week. With any type of radiation, if the source was powerful enough to kill everyone in a 100m radius within 24 hours, then by definition it is at least powerful enough to set stuff on fire; whereas if you used lots of small sources, e.g. plutonium-238 dust, you have the dispersion problem again.

To make everyone in a city-sized area drop dead at once, short of brute mechanical force, there's no know way to do that (which is arguably a good thing). You could electrocute them all, but you'd need an environment specially set up for it.

In the realms of handwaving, you could have a memetic virus or poison-releasing implants distributed in advance and triggered by a radio signal / musical cue / etc. Or [some kind of quantum woo] could temporarily change the ionization enthalpy of sodium atoms, causing people's nervous systems to shut down but without visible chemical side-effects. Or a wizard could teleport everyone's hippocampus into the sun.

Answer 13

Perhaps a bit less hard scifi, but say they invented teleportation a la Star Trek, but due to power constraints full body teleportation is too costly (and certainly too costly to affect an entire warfront at once). However targeting a cross section of arteries leading to the brain, either surgically removing them or placing a block/blood clot/foreign object instantly shutting off blood flow leads to everyone targeted appearing to instantly die for no apparent reason with minimal energy costs.

Answer 14

I think a biological weapon in such a war would be a airborne transmissible Coma Inducing disease.

You can add a lot of Sci-fi to the idea and there are lots of paths to follow, connect with the "what consciousness is" question or just move onto the consequences of having a whole world of sleeping bodies that will slowly die of dehydration and hunger.

Answer 15

Genetic magnetic weapon

The weapon would change the magnetic reliance of a cell, and the cell will disfunction for a very short time, which lead to death of body. Migratory birds rely on its magnetic sense (towards the Earth's magnetic field) to fly across the earth. If migratory birds' magnetic sense is disturbed somehow, when the migration season comes they will start to fly but to the wrong direction. And very likely die half way.

This damage can be exerted to the individual when it is against an individual. This damage can also be exerted to the mass when a weapon is used to manipulate the Earth's magnetic field.

Extremely Low Frequency Magnetic Fields

Most human invented devices do not significantly disrupt long term functionality of the genetic code as they are at or under 2 Tesla of strength. The generation of extremely low frequencies seems to be a factor in potential damage to the genetic structure.

Study of genetic damages from ELF magnetic devices.

This implies that a device that is disruptive to genetic structures or even brain waves would have to be both higher strength than any normal human devices, and would also have a short range and would have to be deployed strategically in geographical terms.

Magnetic Strength for Weaponization

The threshold seems to be at about 15 Tesla or better for significant genetic disruptions.

Plant Cell Disruption at High Magnetic Fields

Since higher strength affects the range, the strength of such a weapon would be a multiple of 15, such as 30 Tesla or higher. There is no guarantee that other lifeforms would not die, since there is no particular way of tuning this to only affect human bodies. The need to generate and use high amounts of power would be a limiting factor, so advanced power generation may be a factor in the use of such weapons.

Answer 16

Microwave Egg Brain

If you heat a bowl of damp rice in the microwave the inside heats faster than the outside. You have take it out and stir and put it back in. This is more extreme for an egg. The wet inside of the egg heats faster than the dry outside because microwaves work my vibrating moisture to create friction.

Your head is like an egg. It has a dry skull on the outside and a wet brain on the inside.

Your death weapon works like a big microwave oven. It creates a bunch of microwave radiation. Not enough to melt the dry outsides of the victims, but enough to vibrate their squishy brains until they become jelly.

Of course the brain jelly is still contained in the skull. Unless you have the bright idea to crack open the skull then it will remain a mystery.

Answer 17

Way out of my league here .... An air burst bomb detonation or series of detonations causes infrasonic sound waves of a frequency and intensity that damages the liver. The liver damage {somehow} causes the upper esophageal sphincter to go into spasms preventing the victim from being able to breath. They asphyxiate.

Answer 18

A gaseous chemical inhaled by the participants did it

In the film Serenity (Firefly Universe), [spoiler tags used in case you've not seen it]:

the Union of Allied Planets added the Pax to the airprocessors of an entire planet, Miranda, to pacify the populace. However it worked a bit too well, and caused 99.9% of the populace to stop doing anything at all (including eating) and just waited for death to come. The remaining 0.1% of the population became ravenous killing maniacs committing all of the worst crimes humans can.

In your world, peace activists could use this same substance in an attempt to stop the war...but it had the unintended side effect of killing everyone!

As for being noticeable, if it is dispersed at a sufficient altitude, by an air-burst munition, in the right conditions, it would fall over all of the combatants not leaving any chance of escape.