How does the fact that energy cannot be released as sound in a vacuum affect events occurring in space? Since sound cannot travel in space, is the energy that would have caused the sound used somewhere else? Would it be enough energy to have to account for it in certain calculations? For instance, if you were doing a calculation concerning a collision on Earth as opposed to a collision in space, would this need to be accounted for?
 A: Sounds comes from the vibration of an object causing the gas around it to vibrate. This, of course, carries away energy, so the vibration of the object is damped as sound waves are produced. In space (assuming a true vacuum here), if you cause an object to vibrate, it cannot shed energy through surrounding gas, because there is none. Instead, the object will either continue to vibrate, or it will heat up (microscopically, this is more or less means the vibrations become more random/less coherent).
The object may find other ways to shed energy efficiently. For instance, hot objects radiate pretty efficiently, the blackbody power emitted goes as the $4^{\rm th}$ power of the temperature, so even a modest increase in temperature from vibration could cause a substantial increase in electromagnetic radiative output.
I don't have time to try a calculation like working out the difference between striking e.g. a cathedral bell in air vs. in vacuum, but it would be neat to know what fraction of the energy comes out in sound and in light in each case, and the relevant damping timescales and so on.
