It depends on how good a vacuum the explosion takes place within, and the quantity of ejected matter. In most cases, the shock wave will just be the matter front moving at you. consider a supernova explosion, and you won't find many explosioins bigger. You have an electro-magnetic radiation front, and a matter front, probably in the form of plasma. Probably it will knock you around (understatement) if you get too close. You could theorize a gravity-wave front, but that's all conjucture and theory for the time being. I don't believe there has been any concrete proof of gravity waves.

The explosion will continue nearly indefinitly until the minimal space medium absorbs it. The likely mass of particles hitting an object like a ship is going to be minimal. So the effects of explosion are minimal. On earth the mass would include the surrounding air heated and expanding from the explosion. In space, there is not so much air and heating it won't do much. Those 1 per meter Hydrogen atoms are already very very hot. There's just so much space between them that they do not transfer that heat to objects.

As for what the reactions are ... shockwave strength would be solely based on proximity to the explosion. Since there is more surface area (spherical versus ground shockwave) to disperse the kinetic energy of the blast you would have to be fairly close (pending supernova or high yield nuclear type explosion) to take any significant damage. How close would, as said before, depend on the amount of mass and energy involved. The larger the mass and energy (a star versus a missile), the farther away it could damage.

The big worry, though, is electromagnetic energy with certain types of explosions (EMP = Electro-Magnetic Pulse). Since space is not a true vacuum (we know of "solar winds" and there are many other theories regarding dark matter and other forms of matter (gravitons, et al), both atomic and sub-atomic) that an EMP blast could use to discharge energy into a ship. An EMP blast could, and once again this would depend on proximity, disable all unprotected electrical based systems in a ship.

The best example of this our sun, Sol. Despite it being ~150 million km (~93 million miles) away, the energy it releases effects things on Earth. During high sunspot activity periods we have found that radio waves travel shorter distances, due to the electromagnetic energy the sun releases. We have also detected EMP blasts from supernova stars on Earth. So the EMP would be the more troublesome aspect, imho, than the physical shockwave (unless the detonation is right next to you).

Granted, all of this is theoretical. The US and Russia have done high yield explosive testing in high atmosphere, but to my knowledge there have been no official scientific tests on how explosions work in outer space (outside the planetary field) and deep space (outside a solor system) work, and how objects, such as ships, can be damaged. So anything we say here is pure speculation, unless we have a member of an advanced alien species here that we don't know of.

Jammrock

[This message has been edited by Jammrock (edited April 19, 2006).]

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but to my knowledge there have been no official scientific tests on how explosions work in outer space

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True, but . . .

I could be wrong, but I recall hearing that much of the research data that lead to the development of -- for lack of a better term -- "shaped charges" (explosives that direct a disproportionate amount of their energy into one direction) was gathered from experiments that studied how explosions work in space. Maybe it was just zero-G. But . . . the point being . . . I don't think we're working in a complete vacuum here. (yes, the pun is most DEFINITELY intended) There should be some info out there SOMEWHERE detailing how explosions work in space.

Or, (and this is a distinct possibility) I may have no clue what I'm talking about.

-Falken224 (posing as Corin)

(edit)

It looks like I probably am wrong.

http://www.llnl.gov/str/Baum.html -- Interesting article about shaped charges.

(/edit)

Yes, too close and you'll still die. Likely of being cooked to death, though. Or if there are solid chunks it could be like a shrapnel effect. Messy, and it wouldn't look much like blast damage.

If you have an explosion that, rather than being in vacuum is inside of something large and fairly dense (like star), and that explosion is powerful enough to cause large quantities of matter (millions of Earth masses) at relativistic velocities, then this should produce "gravity waves", just as suddenly moving a charge at relativistic velocity through, say, a wire will produce "electro-magnetic waves".

No, you will not feel these "waves". The trillions of kilotons of fiery plasma incinerating you will prevent you from feeling much of anything else. But scientists with delicate and very expensive instruments might be able to detect them.

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start by clearing your mind of all terms that rely on waves of any kind

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The entire structure of your explosion "inflates" rather than "blasting".

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So the sphere of the explosive energy (there is lots of energy in space, it simply does not have a lot of mass to react with) would simply expand until it is harmless. Thus you would need to be in close proximity for the energies of a manmade explosion to cause any significant damage.

Such hypervelocity rounds would penetrate armor designed to protect a ship from the intense radioactive threat of 'standard' warheads (the 'cooking' effect Survivor mentioned). There would most likely be an explosion at the point of impact, though such an explosion would be far less theatric than cinematic depictions. And that's leaving out the probable ignition of the ship's internal atmosphere (which would burn until the air mixture grew too dilute, due to the hull breach). Don't forget secondary damage from a hypervelocity round, as well. If one punched through your armor and managed to stay intact long enough to destabilize a power plant...well, depending on the power source, there could be nasty side effects.

Just a thought.

Actually--and my grasp of physics is far too limited to figure this out by myself--would the very nature of extra-atmospheric conditions limit the performance of kinetic-based weaponry? Damn...just thought about that, after my whole argument was written. Oh well.

Inkwell
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"The difference between a writer and someone who says they want to write is merely the width of a postage stamp."
-Anonymous

The problem with a gauss cannon or railgun is that it's a "dumb" projectile weapon. You shoot and then it goes straight - unless you make a "smart" shell that can maneuver. Chances are that a ship could dodge a dumb projectile unless you were at very close range, or the ship being fired up was very slow.

You also run into the potential problem of too much space garbage with a non-explosive or energy based space weapon. That projectile will keep going until it hits something. Who knows what you might start running into if you keep leaving too much junk shooting around a solar system or "shipping routes."

That's just my thoughts on the matter. It's a question my imagination has tinkered with for a long time, so I've put some thought into a lot of possibilities.

Jammrock

If a warhead's yield has less destructive effect in space (as already discussed), an alternative would be necessary to begin with. Based on what others have said, would not the use of a warhead in hypervelocity weapons defeat the purpose of using them in the first place? The fact that the weapon uses kinetic energy more than electromagnetic/thermal energy solves the problem of limited effect.

The problem of the projectile being unguided remains...though such a projectile would not suffer from countermeasures. Also, capital ships would be the slower vessels of a space fleet...the velocity of the railgun/coilgun projectiles would likely outrun them at sublight speeds. Also, railgun rounds lose inertia in an atmosphere due to friction and the like...they would probably retain more kinetic force in a vacuum, and thus possess a greater range.

In any case, the explosion from either a missile with a payload or a railgun/coilgun projectile would be significantly low-key, compared to what is seen on television and in the theaters. However, that low-key effect would only be true if the explosion were viewed from the ship's exterior alone. Inside you'd have explosive decompression, structural damage, atmospheric ignition, etc. to deal with. Not pleasant, by any stretch of the imagination.

Inkwell
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"The difference between a writer and someone who says they want to write is merely the width of a postage stamp."
-Anonymous

Where was I?

With something like a missile, however, you can make it out of a non-metallic substance and still use it. They do have plastics, composites and other substances that could withstand the heat from a thruster of sorts.

So a lot of the feasibility of space weapons would depend greatly on the countermeasures of the opponent. And since writers can make their own strengths and weaknesses within their stories, whatever you want pretty much goes. As long as you don't completely ignore the basics. As one of the rules of anime states, "the laws of physics only apply when they are convenient."

The railgun/gaus cannon would give the projectile speed without the need to use a lot of fuel. The encasing breaks off after launch, maybe attached to the ship to reduce waste and space trash. A hardened composite guided 2nd stage could penetrate the hull at high speeds and detonate inside.

You'd have atmosphere within an armored shell (explosive inside metal = artilery shell) to react with the explosive, in addition to the "reactors" or power source of the ship. That could make for one big boom.

Cool.