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Sound In Space

  1. Jan 13, 2009 #1
    As I lay here at 2am contemplating the vastness of the universe, and scanning my DVD collection so I can either put myself to sleep or have some stimulus to pull an 'all-nighter', I happened to come across Space Balls.

    Now if you have never heard of it, it is a 1980s parody of Star Wars that got a cult following and was referred onto me by my parents when I was a teenager. My point being as I watched this movie, staring a young Bill Pullman (the President from one of my favourite movies Independance Day - which, got me further interested in this topic) is that during the space battles and finale, just like Independance Day, there are inevitably explosions (I won't spoil it but being based around Star Wars you should already know there is going to be a big boom somewhere in it).

    As most do now with any science fiction movie, my immediate thought was, there can't be a boom because there is no sound in space. But then I began to think about it. I've done some research over the last 30 minutes and as far as I can read, there is no sound in space (bar the ultra-low frequencies that can be detected due to the sparsely placed hydrogen atom). Another thing I found alot of was flame about explosions in science fiction movies.

    Now I ponder this statement because as far as I can read hearing sound is a direct result of vibrations through a medium which is translated by our ears. And even the Department of Energy in the United States of America had this to answer of a high schoolers question of "Is there sound in space?"

    Department of Energy, United States of America:

    Sound needs a medium to travel in such as air. There is no such
    medium in space. The myth of sound in space has been promulgated
    by Hollywood in movies and tv: rocket engines firing and explosions
    would have little impact on the audience if there was no sound.
    A little anecdote: Harlan Ellison, one of our preeminant modern day
    science fiction authors, is the creative consultant for the tv show
    "Babylon 5", and has declared publicly that he will continue in that
    capacity only as long as we don't hear any explosions in outer space!

    Now not to discredit or disagree with the Department of Energy, who undoubtadly employ people who are smarter, and can probably spell better, than a lowly university student studying advertising like me, but I can't help but have a few questions.

    For as long as I have seen science fiction movies, I have heard the complaint that explosions in space have no sound. But, as in Star Wars, which I will be using as my example - particularly the Death Star explosion (either one, take your pick, and sorry - hope I didn't spoil it for anyone), there are several things that to me seem to warrant a big boom explosion.

    1/ The Death Star, as with other spaceship that go boom, are supposedly large vessels, that are supporting tens, hundreds and if not thousands of lives. According to these movies these creatures are humanoid or similiar and require oxygen to breath.

    2/ So, when you have a vessel the size of the Death Star, or say, Mother Ship from Independance Day - you are talking about gigantic proportions of gas.

    3/ When these vessels explode, would these gases not expand into the 'space', providing the medium for the sound of the boom to travel along it? Although I do not underestimate the power of the dark side, surely in any explosion of a vessel, ALL of the oxygen wouldn't be consumed, leaving some to stay in the space that was 'empty'.

    So to put it simply, when the Death Star was destroyed, wouldnt the oxygen and gasses providing life support inside the vessel then provide a medium for the sound to travel through as the explosion rippled through space?

    The only question then is how far would the gas be able to carry the sound away from the explosion site (at a human hearable frequency), and would it be far enough to reach the vantage point depicted in these movies, so as if the audience were actually there, where the camera was, they would hear it.

    Anyway. That is the conundrum I face tonight as I ponder the stars and decide if I shall sleep tonight or go have a shower to keep me awake.

    Happy thinking to you all.
  2. jcsd
  3. Jan 13, 2009 #2


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    A good point.
    Ultimately the cloud of gas from inside the explosion would reach your ship and if it was still dense enough it would make a noise - although wether that was sound or just the impact of debris is hair splitting.
    The other 'explanation' I heard was that it is the electromagnetic field from the implosion distorting the hull of your ship which makes it creak.

    Some film makers do try and come up with a rational for everything eg. Ridley Scott.
    At some point it is probably time to think - it's only a movie and reach for the pop-corn!
  4. Jan 13, 2009 #3


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    In a vacuum, a pressure wave would propagate much differently then in an atmosphere. I don't have my fluid dynamics textbook around, but maybe someone with more knowledge of CFD could run a simulation to see how the gas disperses (and post pretty pictures).
  5. Jan 13, 2009 #4


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    Life support gases aside, the spaceship's vaporized/ing material is an medium that will transmit sound. It would likely be somewhat different than an air burst since, as mentioned, the gases and solid debris will propogate differently in space. For example, rather than the reverberating *boom* (which comes from wave after wave of pressure), you might get sharper, shorter noises.

    As for explosions and flames, have a look at some of the footage of the lunar module when it takes off from the Moon and makes its ascent into orbit. It is nothing like flame at all - the propellant does not form a ball or pressure wave, it comes out like a spray of discrete particles, travelling in straight lines (well, parabolic lines anyway).
  6. Jan 14, 2009 #5


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    I have heard some of the arguments against explosions taking place in space, and you are completely correct, the air inside spaceships would make explosions possible. The propogation of sound would be dependant on the gasses actually reaching your location first, and then there could be sound. Of course, this is no different from the problem of Hollywood explosions transmitting sound instantly to people who are hundreds of yards away.

    But I have noticed that, in many of these space battles, you can also hear people talking to one another, or talking to themselves, even when the audience's point of view is from outside the cockpit. So, what we are supposed to be hearing is what it sound like inside the the vessel.
    Last edited: Jan 14, 2009
  7. Jan 14, 2009 #6


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    This is a slightly different thing. The audience has no trouble accepting what is obviously montage, i.e. a visual of outside the ship, with audio from inside the ship. No one takes this so literally that they think the screenwriters are suggesting the voices are heard outside the spaceship. This is used all the time on TV drama shows when you see the outside of a building (where the characters are) with voice overs. This visual is what's called an "establishing shot".

    But that's not the same thing as visual showing an explosion while audio is sounding an explosion. It's not like we're supposed to think that the explosion we as the audience hear is what's heard inside the spaceship. If that were so, the screenwriters would be trying to suggest that we are hearing the Death Star explode from inside 2 X-wing fighters, 1 Y-wing fighter and an Aluminum Falcon. Except they're not even in the shot when it happens.
  8. Jan 14, 2009 #7


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    I wonder why it is that movies and TV shows alike continue to portray sounds and explosions in space, given that it is common knowledge that these phenomenon are impossible.

    Perhaps, because without sound or characteristic explosions, the scene just seems to eerie. Several of the flight scenes from Firefly, for example, seem extremely cold and creepy without any sound as we see the ship flit about through space. Similarly, in 2001: A Space Odyssey, the scenes in space without any sound are utterly distressing to me at times. It's just so strange and striking, it probably wouldn't fit the mood of so many popular movies anyways.
  9. Jan 14, 2009 #8
    I am not sure how true to life it was but the video game Dead Space had some action on the outside of the hull of a space ship, in a vacuum. They totally changed the sound it was early silent and the sound of the weapon in your hand was extremely muffled and you couldn't hear the freaky zombie things sneaking up on you. Super freaky even if it was or wasn't realistic.
  10. Jan 14, 2009 #9


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    I have wondered why this is done also. But still, delaying the sound of an explosion due to distance by a good 1-2 seconds would be confusing to the audience.

    Common knowledge to a good proportion of the adult community. But how about the children that watch these action-packed movies as well? Surely most of them wouldn't realize that the sound shouldn't be heard. if there were an explosion, accompanied by no sound, not only would the intensity have a very low appeal on the audience, but questions from the children would start flying...
  11. Jan 14, 2009 #10
    If I had a child, this is exactly the very kind of question that I would love him or her to ask me. Au contraire, this is exactly the kind of thing media should emphasize.
  12. Jan 15, 2009 #11


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    Our movies and our TV are not our primary educational tool, they are our primary entertainment tool. Movies & TV shows are the way they are for dramatic effect. And contrary to what many of us science/tech-buffs like to think, scientific accuracy is not dramatically effective*.

    * in an action film (such as Star Wars) that is. It worked well in 2001 because it is a science fiction film - with a particular outer-space-like mood.

    Star Wars: excites you
    2001 : makes you think
    Last edited: Jan 15, 2009
  13. Jan 15, 2009 #12


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    Because our movies and our TV are not our primary educational tool, they are our primary entertainment tool. Movies & TV shows are the way they are for dramatic effect. And contrary to what many science/tech-buffs like to think, scientific accuracy is not dramatically effective.
  14. Jan 18, 2009 #13


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    Those are exactly the kinds of things that made Firefly attractive, IMHO.
  15. Jan 18, 2009 #14


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    Yes. They don't make many actual science fiction films and shows these days. They make "futuristic action" shows.
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