From my very limited understanding sound is basically the vibrations in particles/atoms/ whatever, and light is some sort of weird mix between energy and very small particles, so why can light not carry sound? ( sorry if grammar/wording is bad high)
Edit: woke up to all of this, thank each and everyone of you so much!
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Sound is simply pressure waves encoded into a substrate, such as air or water. What you hear is your body sensing the waves of pressure and interpreting it in your brain. Light can encode information such as a representation of sound, however it needs decoding and transmitting as pressure or vibration for you to hear that reconstituted sound.
Haven’t read any responses so this may have been mentioned already, but light is capable of carrying sound data. That’s part of what wifi/mobile data/bluetooth/etc does.
I want to address this question from a slightly different perspective. What is “sound”? Sound is what we call the experience our brain gives us when it is interpreting changes in atmospheric pressure, which it does through our ears. Which is to say, “sound” is not something that exists outside of some kind of interpretation. It is what is called _qualia_, in the same way that “color” is how our brain interprets the frequency of light. All _qualia_ involve an interpretation of some kind of physical phenomena (pressure waves, light frequency, etc.), but are something beyond that. _Qualia_ are very hard to talk about in precise terms — those of us who can hear know exactly what it means to hear something, and those of us who can see know exactly what it means to see something, but to translate the subjective experiences of seeing and hearing into more objective terms has proved basically impossible so far (and are not the same thing as describing the base phenomena that cause the _qualia_; we interpret photons in the 430 terahertz range as being “red” but that does not explain the mental experience of “redness”).
Our ability to perceive the world in terms of _qualia_ evolved over a billion years or so, and the _qualia_ we perceive and the way we perceive them have been highly tuned by evolution to optimize specific kinds of circumstances. So the spectrum of light we can see (“visible light”) is the same spectrum that can pass through air and water, which is very convenient on a planet with an atmosphere made up of air and water. Similarly the range of frequencies we can hear are probably determined in part by what was useful for our evolutionary ancestors (hearing too high or too low might have proven distracting or unhelpful, for example). This doesn’t mean this is the only possibility of what evolution could have gotten us — dogs can hear different frequencies than we can, birds can see slightly into the ultraviolet range, some snakes can perceive infrared radiation — but as a rule of thumb this approach is pretty useful for answering questions of this sort: “because it was evolutionary advantageous for our ancestors — most of whom, we should remember, were not humans! — to have this ability.”
Which is to say: you could imagine a sense-organ that interpreted light as what we think of as “sound.” It would be sort of the inverse of the specialized organs in a bat that allow it to translate sound into 3D imagery (sonar; the neurology of which is complicated and _fascinating_, as an aside). In crude terms, you could imagine making a machine that did this: it would have a camera, and depending on how you set it up, could convert light frequency (color) or intensity (brightness) into a tone or series of tones or something. Would that be interesting? Sure! I could imagine an artist doing something like this, or maybe even someone experimenting with a device that could be useful for the blind. Would it be _useful for navigating the world_? Maybe in some very limited applications (again, maybe one could make this useful for the blind), but in general that would be a very weird way for us to imagine re-mapping phenomena onto our existing _qualia_. It is [famously impossible](https://www.sas.upenn.edu/~cavitch/pdf-library/Nagel_Bat.pdf) to really imagine other _qualia_ in an intuitive way (imagine trying to explain to someone blind from birth the experience of the color “red”), so it would be too much to say that such an approach is impossible to imagine having evolved, but we can say that for us, it did not evolve that way, and it is not clear what advantages it would have over the way things did evolve.
This is not really ELI5, I am sorry. But I thought it was a perhaps interesting way to think about the question.
Sound is a pressure wave. This means particles are pushing on other particles. Light is photons which are wavicles, but importantly for this they are bosons. When a sound wave propagates through a medium, the particles that form the wave front move forward, and push on the particles in front of them, then move back into wherever they were before hand. With light, photons can occupy the same quantum state and can pass right through each other. So if one is moving forward and encounters another one, it won’t push it in the same way it is traveling. This, no pressure wave.
There is another reason as well. Or rather another way to look at it. Light travels at, well, light speed. So if photons are going in the same direction, then they can’t catch up to each other to push them even if they could interact with them..so you would need to propagate the “pressure” wave from the side of a beam of light. And then if they do “move” in that direction it immediately change direction and no longer be going the same way as others and a whole mess gets made.
So the short answer is that light can’t push light. And sound is a result of stuff pushing on stuff.
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