Are explosions in space really that dangerous?


Not talking about your ship exploding, that’s obviously bad. I’m talking about how much damage would a bomb actually do if exploded in the moon for example. I understand there is no atmosphere to push against, but I don’t understand what else appart from the shrapnel could cause damage. Isn’t most of a bomb’s damage produced by the shockwave? And shockwaves cannot be produced in a vacuum, right?
Also, let’s say it’s a nuclear bomb. The radiation is obviously bad, but with some shielding, same here, what damage will it actually do?

In: 236

So a bomb in space acts so different from on earth. First and foremost, as you know one of the deadliest parts of a traditional bomb is the shrapnel as much as the explosion itself. Luckily in atmosphere the air slows shrapnel down after a bit. In space there is no such thing. The shrapnel thrown from a bomb will travel without slowing until it hits something else. So even a distant explosion can send deadly shrapnel speeding towards something a long way off.

Bombs themselves also produce gas. It’s this spontaneous expulsion of gasses and energy that creates the shockwave in atmosphere. However in space that gas is still produced. So the threat of the shockwave is still there. However its effect is less significant than one in atmosphere. That is unless you’re in a pressurized metal space craft. Then the energy of the explosion can transfer into the craft and compromise the pressure sealing leading to all that pressure trying to escape and creating a secondary explosion via rapid decompression.

So they’re equally dangerous in or out of atmosphere. It’s just the danger changes.

u/copnonymous Covers it pretty well. Depending on the explosion, thermal radiation can be significant. That is, the radiation, even if it is non-ionizing, can be dangerous just by heating things up. Proposals for using nuclear bombs to deflect asteroids involve using intense radiation to vaporize part of the surface. The expanding rock vapor is what pushes the asteroid. Something powerful enough to blow up the moon would likely produce a tremendous amount of heat.

Nukes are quite dangerous in outer space. Much of the energy comes out as x-rays. The atmosphere is opaque to them, so a lot of the energy goes into ionizing the air. In space, the x-rays just keep going the lethal distance is much further than on Earth. For a multi-megaton shot, the lethal distance is hundreds of miles.

There is a super nerd website out there that you might enjoy reading. Search for “Project Rho Atomic Rockets” the website you want has a this rocket render covered in equations. Scroll all the way down and you’ll find a blue area with a list of topics. Each one is covered in rigorous detail, discussing the practical and realistic applications of current and hypothetical technology in space. Despite first appearances, they still update it because I caught some images from the series The Expanse.

On the moon, for example, shrapnel travels significantly farther with no significant air drag to slow it down, and with low gravity. It basically doesn’t slow down from velocities on the order of typical bullets, until it hits the ground, or something else. Likewise meteoroid impacts on the moon can potentially produce a lot of fast moving shrapnel/ejecta which travels dozens of km.