Observation 1: Astronomy Cast

Ep. 281 Explosions in Space

    A common mistake in science fiction is how films display explosions which occur in space.  In reality, explosions in space would not be extremely loud and dramatic as they are often portrayed.  

    Explosions require both a fuel and an oxidizer to occur.  In space, there is no oxygen so anything which explodes would have to have its own oxidizer present.  There is also no pressure which would moderate an explosion, drawing it out in length.  An explosion in space would last an extremely short amount of time and would expand outward in a perfectly spherical manner, assuming the explosive device is round.  Explosives such as bullets and dynamite do have their own oxidizers contained in them, so the explosion could occur in space.  In early space travel, it was discovered that if there is too much oxygen combined with the burning fuel in a spacecraft, the spacecraft will explode and be destroyed.  

    Sound from explosions is not heard as it would be on Earth.  The energy reaching you will go down by a factor of 4 in space each time you double your distance from the exploding object, according to the "one over R squared" law.  This is because the shock wave expands in a circular manner in all directions.  Even if you were very close to an explosion in space, you would hear minimal noise.  Energy very quickly dissipates because there is no atmosphere to take in the energy.  A nuclear reaction in space would not be seen because it would become literally a flash of energy.  There is no atmosphere to show the fluorescence of it.  

    Natural explosions in space are much more visible than synthetic ones would be.  Many reactions will occur consecutively.  Expanding gas can show more of a "flame thrower" effect.  Coronal mass ejections are energy releases and are, on our sun, basically magnetic loops.  These can be seen and have been photographed and recorded.  Supernovas are another example of a natural explosion in space.  They are collapsing stars in which atoms are compressed until they break apart.  These explosions are very violent.