Fire & smoke in Space?

Question

In the Sci-fi movies they show explosion in space, how come there is fire and sometimes smoke when there is no oxygen in the universe?

Answer 1

Clearly, there IS oxygen in the universe, just not a lot of it in interstellar space. However, if a rocket IS in space, it probably has its own source of oxygen to burn its fuel, so when the ship explodes, there is likely to be quite a fireball. However, the fireball and resultant smoke would probably dissipate much more quickly than shown in the movies. But that wouldn't be a very exciting special effect, would it?

Answer 2

Well - I'm guessing you mean "there is no oxygen in space". Obviously, there *is* oxygen in the universe ... quite a lot of it, in fact.also - like you say - this is Sci-Fi: Science Fiction, not Science Fact. And it looks cooler...

However:

An exploding space-ship could be from a number of things, such as a fire or explosion *inside* the space-ship (in the oxygen-rich environment inside) that bursts the ship open and escapes into space (where it will be put out, but will still be visible for a while)

Alternatively, the explosion could be from a nuclear reactor inside the space-ship. Nuclear reactors can explode, and the explosion is not burning, and has nothing to do with oxygen (for example, nuclear reactions are what power the sun, not "burning oxygen").


Interestingly though, in "zero-gravity" (actually free-fall, like inside an orbiting space-shuttle) normal fires won't burn for very long.
When you light a match, the distinctive shape of the flame is due to the heat energy heating up the gasses involved, and causing them to rise by convection; this is why flames always point upwards. In free-fall, this doesn't happen (there is no convection in free-fall), and the CO2 produced by the flame will stay exactly where it is, and will therefore snuff-out the flame pretty quickly.
If you want a fire to burn in free-fall, you need to engineer a breeze to blow the CO2 away.

Answer 3

Well, I see lots of technical answers here but the real reason is a lot simpler. They're movies. Sci-fi writers for movies are perfectly aware there's no air in space and that sound doesn't travel, but those aren't elements that Average Joe moviegoer is used to experiencing.

When something explodes, you get absurdly big fireballs in movies. It could be an exploding watermelon and you'd still get a giant fireball. This isn't reality, this is a movie. And when things go boom in movies they go in a big way. The laws of physics take second place to the laws of spectacle.

As for sound in space, people just aren't used to long periods of silence in a movie (or anywhere else). Making a truly silent space scene is always considered a bit risky.

Answer 4

All explosives make their own oxygen, ammonium nitrate is commonly used as an oxidizer in commercial explosives. That is why they work underwater. Smoke and steam are a by-product of an explosion. Fuels like petrol do not make oxygen, which is why you need a carburettor on a petrol engine.

Answer 5

There can only be fire and smoke where there is oxygen.

You can see vapor in space, as a leak would cause the atomsphere to condense into a vapor just like what happens when you release hairspray from a container under high pressure into the air which has less pressure

Answer 6

explosion of what? a spacecraft? There would be oxygen on the space craft which would allow for the burning, though short lived.
Besides it is Sci-fi. They miss things.

Answer 7

There can only be fire and smoke where there is oxygen.

You can see vapor in space, as a leak would cause the atomsphere to condense into a vapor just like what happens when you release hairspray from a container under high pressure into the air which has less pressure.

Answer 8

If there was no oxidizer how would chemical rockets work in a vacuum?
Rocket fuels and explosives all provide their own oxidizer. You can have an explosion in space and from outside the blast area you would not hear it but inside the gas cloud, an explosion would produce, you would most certainly hear it.

Answer 9

Perhaps the oxygen from inside the ship could fuel a small fire, but you are correct, and no noise would occur either.

Answer 10

in sci-fi movies using imagination of humen mind.in the space explosion of stars made by its atomic energy and rocket made fire by its fuel tank lequid. there are oxigen in space but it its few ,so fire in space made no smoke.