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Take for example the opening of Revenge of the Sith. We see spaceships fighting with other spaceships using laser canons and missiles. Then when one spaceship is destroyed, we see fire and heavy black smokes coming from it.

  1. Does that mean in space, fire can still burn, even though there is a vacuum?
  2. If there would really be a space war, can spaceships really be destroyed and explode?
Rogue Jedi
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mahen23
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    Fire can burn as long as the three things needed to make fire are present: heat, fuel and oxygen. The fire will exist until it exhausts its supply of any of these three elements. – OghmaOsiris Jun 27 '11 at 16:58
  • check this question http://scifi.stackexchange.com/questions/1825/why-and-how-can-you-hear-explosions-in-space-in-star-wars – Sinan Jun 27 '11 at 17:43
  • could be wrong, but i'm pretty sure it doesn't even need to be pure oxygen - something like hydrogen peroxide ought to self-catalyse if you hit it with something like a 'laser'... – HorusKol Jun 27 '11 at 23:09
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    what is explosion anyway? heat, light, and sound. Among these, light would have no problem traveling through vacuum, heat would be carried by the light through radiation, but there should be no sound. There is going to be lots of debris, and the debris would go straight without any gravity or air resistance to hold them. – Lie Ryan Sep 15 '11 at 03:25
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    @HorusKul - hydrogen peroxide has been used as a rocket propellant since it will decompose into steam and oxygen so it would still fall with OghmaOsiris's comment – Strangeland Jan 13 '12 at 21:13
  • We should historical lock this. – Valorum Oct 03 '17 at 15:20

9 Answers9

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Yes, provided there is an oxidizer. A spaceship with liquid hydrogen and liquid oxygen will blow up quite well in the vacuum of space. Chemical explosives will also explode in space since they function by breaking weakly bonded chemical components; no oxygen is necessary. Nuclear explosions can of course occur in space, too. However, in space, there is no atmosphere to transmit sound from the explosion to the observer, so it would appear to be silent.

The United States military in the 60's performed a series of nuke tests in outer space, and found out what EMP can do, when they wiped out Hawaii's electrical grid for a few hours.

Paul D. Waite
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ykombinator
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    Not an "oxygen source" per se, but an oxidizer (which is a bigger class). – dmckee --- ex-moderator kitten Jun 27 '11 at 23:37
  • @dmckee : Yeah, couldn't find a better word at that moment. :P Will correct that. Thanks for pointing out. – ykombinator Jun 28 '11 at 04:36
  • Technically, nuclear devices (NOT weapons) initiate, they don't detonate. But this isn't physics.stackexchange.com – Jeff Jun 28 '11 at 05:03
  • how about smokes (which suggest that some dark gaseous compound being created), or sustained fire when there's limited oxygen. Are these possible too? – Louis Rhys Jun 28 '11 at 06:20
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    Certainly. Smoke wouldn't behave as it does in atmosphere or gravity, but the byproducts of combustion are still created in space as they are on a planet; in fact you might think more smoke would be created because with such a limited time to burn before the vacuum dissipates the concentrated burning gases and other components, the combustion wouldn't be complete or ideal. – KeithS Sep 16 '11 at 23:45
  • Just to note that EMP doesn't actually happen from a nuke in outer space, only in the upper atmosphere! (Its the combination of ionised fast-moving electrons stripped off air molecules by the gamma ray blast moving in the Earth's magnetic field which produces an EMP) – Nick Dec 04 '13 at 13:57
  • @Nick EMP could happen from a nuke detonated in space, as that too would create a gamma ray burst (heck, we've had it happen at times from solar flares and gamma ray bursts coming from other stars). Of course a burst in the upper atmosphere might produce more gamma rays as atmospheric gasses are bombarded with early radiation and may themselves start to fission, but from what I remember from nuclear physics those secondary reactions would produce lower energy X-rays rather than gamma rays, not taking part in the EMP. – jwenting Dec 06 '13 at 07:21
  • @jwenting Gamma Rays are not EMP. EMP are radio waves of all frequencies released in huge numbers when fast moving electrons are deflected by the Earth's magnetic field. Without a planet, a magnetic field and an atmosphere to provide atoms for the gamma rays to ionise, you don't get an EMP. In the upper atmosphere you get a huge EMP, out in deep space, you get just the gamma ray burst! – Nick Dec 06 '13 at 09:13
  • @Nick I know that. Gamma rays trigger EMP however, by exciting atoms that release those radio waves when falling back to their natural state. You won't get that effect when the X-rays emitted by secondary fission products interact with other atoms, they're just not energetic enough. – jwenting Dec 06 '13 at 09:38
  • @jwenting The EMP from a nuke is from ejected free electrons moving at high speed through the Earth's magnetic field. Its not from the excited atoms decaying. Without a planet with a magnetic field you don't get an EMP. – Nick Dec 06 '13 at 10:01
9

Explosions can happen, just not in the way that is depicted in the movies. (this is how stars are created/destroyed, etc.)

Here is some nuclear testing in space. For an example of an explosion happening.

Valorum
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OghmaOsiris
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A ship which has lost structural integrety and is no longer able to contain the pressurized gas of its atmosphere will indeed explode. The pressure of the escaping gasses would likely rip apart any structure that had been weakened. In addition rapid expansion of gases from the heat generated by an explosion as well as the increased pressure from it would add to these forces. For a small time the area around the ship would no longer be a vaccuum until the pressure from the atmosphere had been disipated. During this time smoke and fire would be reasonably expected. This probably goes on longer for the movie than it would in real life and more dramiticaly.

Chad
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  • The gases would "explode" into the vacuum, at a velocity similar to the speed of sound at the original temperature. They would also cool very rapidly, because of the rapid pressure drop. Almost all stock explosion footage used show the effects of the explosion expanding into a pressurized gas, and they are quite poor as far as realism is concerned. – Omega Centauri Jun 28 '11 at 20:30
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    I think I said the same thing "This probably goes on longer for the movie than it would in real life and more dramiticaly." – Chad Jun 28 '11 at 20:39
  • Chad, my point was that lacking backpressure, the flame fronts seen in most explosion stock footage is horribly wrong. Its not just a matter of running out of stuff to burn, but the gas and debris thrown out encounters no resistence to slow it down. In some sense, the explosion happens for a very long time measured in years, although the density of stuff in the explosive cloud becomes very small pretty quickly. – Omega Centauri Jun 29 '11 at 16:50
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    I agree and any flaming debris barely missing the cockpit is unlikely to be flaming. However having never actually blown up a space shipe the size of Rhode Island I can not say that for sure. I am up for experimentation if you are though :p – Chad Jun 29 '11 at 16:55
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    "Loss of structural integrity" by itself is not going to cause any explosions (see Apollo 13 and numerous pressure lose events in aircrafts). Measly 1 atmosphere of pressure difference is not nearly enough to cause any catastrophic effects in a well designed containment structure. – oakad Dec 05 '13 at 06:18
  • @oakad - Will they explode is different than can they explode. The question here is can they explode. The other thing to consider is what happens when suddenly a projectile or energy beam destroys that structural integrity with enough energy to cause the one atmosphere to quickly heat up due to an extreme amount of energy being absorbed all at one time. – Chad Dec 05 '13 at 14:50
  • Sure. The only problem is that air is very poor heat conductor, so by the time internal atmosphere heats up the metal shell of the vehicle would be already in the vapor state. :) – oakad Dec 06 '13 at 00:16
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The fire will most likely be extinguished in short order when exposed to the vacuum of space as the O2 will dissipate quickly. A fire inside of a space ship will form a spherical shape until extinguished as shown at http://quest.nasa.gov/space/teachers/microgravity/MGprim1.html

Waif69
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Yes, not all explosions require oxygen as a fuel. Your standard flame requires fuel, space, and oxygen, but chemical fires can happen without the need for oxygen.

phantom42
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Gabronthe
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If there is damage to their main power plant, it's possible for that system to explode. Given that they're worked on by unsuited people, the power plants are surrounded by breathable atmosphere.

This could provide the fireballs we see, as the explosion consumes the ship's own life support.

Jeff
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    One Babylon 5 episode ("A view from the gallery") illustrates this point. There were two races fighting, humans and aliens. A red explosion was identified to be from a human casualty and a green explosion one of the aliens. That was supposedly due to the ship's atmospheres. [http://babylon5.epguides.info/?ID=998] – Stephen Eilert Nov 03 '11 at 16:22
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Flames are gases so hot that they glow and emit visible light. Flames are heated by intense combustion - fire. If the same gases are heated to the seme temperatures and pressures by other means,, they will glow the same.

Spaceships can explode from various causes in outer space. Some types of explosions cold causes release of gases heated to the right temperatures to look like flames. Some types of explosions could release lots of dust or soot, etc. looking like clouds.

Some of the experts who answered before have said that e chemical explosions in a vacuum will not look like special effects explosions filmed in an atmosphere.

So fiery and smokey explosions in space are rather so-so in plausibility.

I personally prefer to see a blinding flash and then part or all of the spaceship vaporized and expanding from the site in a rapidly growing sphere which at first looks as bright as the sun but as it expand and become thinner and thinner becomes less bright and begins to be transparent.

M. A. Golding
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You should first define explosion and burning.

Getting a lot of light or radiation is one thing. Getting the various parts of the ship to fly apart is another.

They are not necessarily connected. And there is also the issue of the time scale. When stars form, before ignition of the nuclear reaction, there is outward radiation pressure from the heat generated by the star internal pressure. This radiation pressure dislocates the cloud surrounding the star, which is really a very slow explosion.

Now, to get heat and radiation from the spaceship, all you need is an energetic phenomenon. The source may be the weapon used, producing energy by whatever means, or internal reaction in the ship (reactor core fusion for example). The energy source of a device necessarily contains all the energy that can be provided to that device. If all that energy is released in a very short time, you do get a very energetic event with dramatic consequences. Typically what you observe when the fuel tank of a car is on fire. But a battery cell with as much energy is as dangerous if it can release the energy quickly.

It could also be some combination. In the chemical case, oxydizing reactions are the more common, possibly the more energetic, but they are not the only ones. What matters is to bring something at a high enough temperature so that it can change to a new internal organization that has less energy, the left over energy being dissipated, This can produce EMR and light (flame, if you wish, though not necessarily the candle kind). The energy can also heat various parts, turning some materials into gas, and increasing the pressure of gas, so that it expands and makes other things fly apart. It may also be that the gas is directly produced by the chemical reaction as in the case of gun powder. Radiation can also push things, if there is enough of it.

Things flying apart may also be due to pressure of preexisting gas that will push on the bulheads and hull of a vessel that has lost structural integrity. However, given the relative masses of the ship structure and the gas, such an explosion is likely to be slow, unless there is another energy source in play. It is probably so weak (without additional energy) that it does not even rip apart the vessel, even with low structural integrity.

If you used a powerful laser to cut a ship in two, the parts would probably drift apart slowly, even though it contained some gaseous atmosphere.

But if you are really good in physics, there are other ways for destroying a ship. For example, you can used a "tider". This powerful device left by the old race can create strong variations of the gravity field in the vicinity of the target. The target is elongated and then ripped to pieces by the tidal effect, without any explosion. No survivors, unless they are tiny. It is the Sci-Fi version of dismemberment, a popular technique some centuries ago.

Clarification added after comments below and a further question.

My answer is an attempt at a uniform presentation of energy/explosion weapons. Then I tried to emphasize that by imagining another kind of weapon, for which I invented the name tider.

My intention was definitely not to mislead people into believing that it existed in some novel or movie. I would have given the reference. I was only trying to avoid a dry presentation.

From answers to the question Was the idea of a tidal dislocation weapon ever suggested in SciFi?, I gather that such weapons have been considered, and Star Wars actually has gravity guns firing gravity bombs. They do explode though, and I was trying to get examples that do not necessarily require an explosion. But all that is of course mostly fiction and imagination.

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babou
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  • Can you provide a reference for this "tider" weapon? They don't seem to exist on Wookieepedia – Izkata Dec 05 '13 at 00:27
  • @Izkata No I cannot provide a reference for it as a weapon in a SciFi novel. Else, I would have done so. I was trying in my answer to get an abstract view of the traditionnal fire and flying apart of usual weaponry, that would explain it independently of the energy source and the momentum transmission medium. I wondered if I could imagine a weapon based on an entirely different principle, and I thought of tidal effect in gravity gradients. Following your hint, I am asking on SE whether it was suggested anywhere. As you refer to Wookiepedia, note that the question was not limited to Star Wars. – babou Dec 05 '13 at 12:12
  • The question was tagged with Star Wars, and uses a Star Wars movie as an example; if a specific sci-fi technology is involved in an answer, I would expect it to have something to do with Star Wars. As it is, it looks like you made up the "tider" on the spot and so at least this part of your answer has no basis in anything except your own imagination. Throws the rest of the answer into doubt, too. – Izkata Dec 05 '13 at 12:17
  • Star Wars was only an example. The tag means that Star Wars is referenced. The question was about the actual physics of space weapons, and was answered as such by everyone. My own answer is no exception. While answering, I was struck by the fact that all these weapons work more or less on the same principle (energy burst), and I thought of underlining the fact by trying to imagine another kind of weapon. This does not mean that my analysis of energy-explosion weapons is deficient. This is science, whereas the tider is obvious fiction - not from Star Wars. I did not mean to mislead anyone. – babou Dec 05 '13 at 13:05
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Explode? Certainly. Form an enormous fireball which keeps on growing indefinitely? Absolutely not.

ex·plo·sion ikˈsplōZHən

noun
a violent and destructive shattering or blowing apart of something, as is caused by a bomb.

synonyms: detonation, eruption, blowing up; More

technical

a violent expansion in which energy is transmitted outward as a shock wave.

a sudden outburst of something such as noise, light, or violent emotion, especially anger.

So a space explosion might be quiet and devoid of much sound amd/or fire (each of which would require oxide, which on turn is not available there), it would certainly be possible for something in space to explode.

Wad Cheber
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