I've been taking a look at Largest artificial non-nuclear explosions . There they mention non nuclear explosions of 3.2 - 2 kilotons occurring 80-100 years ago. Also, one of 4 kilotons around 40 years ago, and one of about 7 kilotons about 55 years ago. Also, humans never tried to create a yield larger than 7 kilotons in purpose. Is there any technical or physical obstacle preventing the creation of a 1 Megaton non nuclear explosion?

Could a race create a 1 Megaton non nuclear explosion?

EDIT: according to a comment, the purpose is "changing global temperature. Supposedly you need 1 megaton bombs to raise the dust to trigger nuclear winter. But you can't use nuclear weapons due to radioactivity."

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    $\begingroup$ Yes, just gather up 1 million tons of TNT and set it off together... $\endgroup$
    – stix
    Commented Aug 1, 2023 at 18:38
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    $\begingroup$ Would finding a way to set-off a volcanic explosion work for you? $\endgroup$ Commented Aug 1, 2023 at 21:16
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    $\begingroup$ This is overtly a physics question, not a worldbuilding question. $\endgroup$ Commented Aug 1, 2023 at 21:47
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    $\begingroup$ Given that we've detonated waaaaaay more than 1MT bombs, 1 block of a million tons of TNT will not cut it. An asteroid impact would certainly change global temperature. If this is something your race wants to achieve, though, there are better ways. Cloud seeding to increase the planet's albedo, or aerosols in the upper atmosphere to reflect more sunlight. Much more reasonable than building conventional bombs of enormous size or dropping an asteroid or triggering a volcano. $\endgroup$
    – jdunlop
    Commented Aug 1, 2023 at 23:20
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    $\begingroup$ Also, I'd love to see your source on dust being the primary particulate, because every major study I'm seeing in ResearchGate suggests black carbon is the primary particulate under examination. $\endgroup$
    – jdunlop
    Commented Aug 2, 2023 at 0:17

4 Answers 4


Yes. We could do that today if we had a really good reason.

All of the high explosives we can reasonably work with have an explosive performance of less that 2x that of TNT per weight unit, so let's say they come up with something that's exactly 2. Now we have to come up with half a million tons of it.

In 2018, total U.S. consumption of explosives was 1.77 million metric tons, so we could definitely CREATE that much explosive.

Conveniently, the physical density also tends to be around 2g/ml, so you'd need a quarter of the volume of the same mass of water to hold it. We're talking 250,000 cubic meters. This isn't an immense volume. It's a third of the loaded displacement of your typical cargo ship. It's still a lot, though.

Part of the problem would be packing it all together in a formation that wouldn't set it off. Let's use a salt mine. The tunnels there are 30 meters tall an 40 meters wide. You'd need 208 meters of that kind of tunnel to hold your explosive. Not too hard.

I REALLY can't tell you how high you can stack RDX explosive. I'm not sure it's legal for me to disseminate that information, so let's just presume that we can pack the tunnels without setting it off.

Setting it off wouldn't be hard. If it's all connected, it'll act like a giant fuse. Setting it off all at once would be impossible, but we can get close. RDX explodes at around 7,000 meters per second, and we're talking a maximum distance of 208 meters. You'd want to position your tunnels so that the explosion started on the outside and worked its way in to get the maximum force in the center.

There you go. A megaton explosion. I wouldn't want to work on that project.

  • $\begingroup$ Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Worldbuilding Meta, or in Worldbuilding Chat. Comments continuing discussion may be removed. $\endgroup$
    – L.Dutch
    Commented Aug 5, 2023 at 20:50

Forget megatons, an asteroid impact can get you gigatons or even teratons.

You can create an explosion with good old kinetic energy - simply smash two things together at high speed, and watch the debris fly. Generally, the more massive the objects and the higher their relative speed, the bigger the explosion. We can find really big, really fast things in space - the asteroid Bennu, for example, is a huge asteroid which has a low probability of hitting earth in the coming centuries, whose impact would be equivalent to over 1000 Megatons. Test missions will be run in the coming years to determine our ability to redirect such an asteroid, but there is no theoretical reason why it can't be done.

One could imagine that with the correct perturbation, one could cause a collision rather than avoid it. Simply redirect a large rock into a collision course with a planet, and you will have caused a non-nuclear explosion far exceeding 1 Megaton.


There some problems I can think of, all related to comparatively low energy content per unit mass of conventional explosive when compare to nukes:

  • simultaneous triggering of all the explosive: 1 million tons of TNT takes a lot of space [citation needed], and making sure that it is triggered with the needed precision so that it explode all at the same time becomes increasingly difficult. Making it explode with the wrong timing could scatter it away.

  • yield of the explosion: an explosion is effective because it concentrates a large amount of energy in a small volume. Due to the lot of space taken by 1 million tons of TNT, using that energy to yield actual damage and not vent it where it is not needed becomes more and more difficult

  • logistic: unless it is for a test, you normally want to have the explosion happen in enemy territory. This means that you cannot normally afford to have a long column of vehicle carrying all that explosive and set it up with calm and attention (see the first point) while avoiding accidental explosions

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    $\begingroup$ 1) is an interesting point. I'm not thinking in an explosion for military purposes. $\endgroup$
    – Pablo
    Commented Aug 1, 2023 at 15:53

Sure. There's not much point to it, but it's absolutely possible if you are determined to do it.

1 actual megaton of pure TNT would have a volume of 549,808,933 liters, which corresponds to a cube of about 82 meters per side. Supposing you need space for structural materials and detonation systems, you could still fit it all into a cube of less than 100 meters on a side. That's about the height of a 30-story building. Definitely a large engineering project, but entirely within our own civilizations capabilities if we had any good reason to bother paying for such a thing.

Figuring out how to reliably detonate the entire mass simultaneously would be tricky... but in real life we are in fact quite capable of arranging quite complex detonation sequences very reliably--that's what both nuclear bomb triggers and shaped-charge conventional explosives rely on! So, again, difficult? Yes. But possible? Also yes.

Finally, that analysis is based on using the type-specimen for guaging megatonnage--actual TNT! But there are plenty of explosives that are more powerful than TNT, packing more explosive capacity into a smaller mass and/or volume. Pick a more powerful explosive, and the cost of the explosive itself might go up, but you'll reduce the size of the structure you need to build.

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    $\begingroup$ The movie quote I use most often on this site comes from The Hunt for Red October. Can you launch an ICBM horizontally? Sure! Why would you want to? - It's amazing how many questions fall into that category, and it's usually because the OP wants to do something outrageously cool but insists on making is scientifically realistic. Which leads me to my favorite movie quote of all time from the movie Oscar. Poole was right! You are an ox and a moron! - a funny interpretation of oxymoron, which is what we have when we launch an ICBM horizontally. $\endgroup$
    – JBH
    Commented Aug 1, 2023 at 17:44

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