Sound in space
Sound in space
Where does the sound go to when you’re in a spaceship in space?
The sound hits the hull, and then has nowhere to go, does it get converted into another type of energy?
Yes, sound is the collective motion of particles in the form of a compression wave. As these waves propagate through a material and scatter off boundaries and inhomogeneities in general, they become less ordered and eventually indistinguishable from random atomic motion (i.e. thermal energy). However, in addition to this, sound waves can radiate away when in atmosphere. In the case of spacecraft, they can only dissipate into thermal energy and can therefore persist much longer. This is actually a problem engineers have to deal with, as unwanted vibrations can cause issues. There's research looking into addressing this by using materials specifically designed to be highly absorbent to sound waves at particular frequencies (i.e. the collective motion of atoms at particular frequencies rapidly decays into random thermal motion).
I've played a few games set in space and some of them have, in their quest to explain differences between the fiction and reality, a "simulated sound" system so you can still hear in space; would something like that actually be possible in real life? 🤔
In principle, you could have a system designed to image your surroundings (using cameras, LIDAR, etc) and perhaps some kind of machine learning algorithm to predict what kind of sound would be expected if the events around you were occurring in atmosphere. I imagine this could work well for simple things like a tool hitting a piece of metal, but would be probably run into issues when the events are affected by the lack of atmosphere or give little or no visual indication that they are occurring. And, of course, you wouldn't be able to "hear" anything outside of the view of your imaging system.
Ok, that makes sense. I expected it to be kinetic into thermal.
But then in a place like the ISS with all the people all the time, does it mean extra heat inside? What would happen if you played loud music? I mean vacuum does not the heat away from you quickly, and there’s nothing to take the kinetic energy. After years of people talking and beeps beeping, where did it go?
Thank you!
I don't have a great answer for you why, but heat must be radiated away from space ships faster than you might think. They have heaters on them to keep them warm. Think Apollo 13 when they turn off all their power, and it gets cold.
The ISS is traveling through a decent amount of atmosphere still, hence they need to boost their orbit occasionally. That atmosphere is probably plenty to dissipate WAY more heat than sound creates.
That doesn't explain deep space ships... But they do clearly radiate heat, if not slowly. But probably faster than what little heat sound creates. (Also think of the cooling phase that James Webb space telescope went through)
Heat can transfer through conduction (basically thermal diffusion through physical contact), convection (bulk motion of matter, like gas or water flow), and radiation. For a spacecraft in low Earth orbit, the pressure is considered ultra-high vacuum, so you basically only have radiation to dissipate heat. Near room temperature, this would be mid-infrared light. The energy in everyday sound waves is very small, so body heat, on-board instruments, sunlight, and perhaps even IR emission from the Earth would be much more important contributors to heat build-up. However, regardless of the heat sources involved, there will always be some equilibrium temperature where the energy going into the system equals the energy radiating away.
To keep things comfortable for the crew on the ISS, there are passive and active systems to regulate the temperature [1]. For dissipating excess heat, large radiators are used. These are basically panels with a large surface area in order to maximize emission of thermal radiation. A closed-loop system is used to circulate fluid, which collects and transfers heat to these radiators. Water is used for some parts, but others have pipes on the outside that use ammonia to prevent freezing. The radiators themselves can be retracted or deployed as needed.
[1] Memi, E. G. "Active Thermal Control System (ATCS) Overview." (2006): 19.
Absolutely. Sound waves are vibrations. Vibrations can be transmitted to other materials. Like electrical conductors, some materials conduct sound better than others. The amount of energy in sound is pretty low, so it's not going to create a lot of heat or light, unless we're talking about sound levels that would be dangerous to not only hearing but would cause death.