Wave Theory

Every once in a while I think of something that just makes me feel all brainy and smart and stuff.  That's what happened to me while walking back from a meeting at work today.  I pictured myself explaining the doppler affect, and how waves work and stuff, to my kids, and bam, the thought just struck me.  Okay, now I have to explain it.  Hmm.

There are two types of waves (at least, that's what I was thinking, and the thought of how these could be combined is the "great thought" that I had):  The first is the kind of wave that travels through a medium, like sound waves that can travel through air, water, or whatever.  With this kind of wave, you basically have forces that keep the atoms apart from each other.  When something tries to push one atom toward another, the other moves further away, toward other atoms, then those atoms move further away, etc.  This causes a little high pressure ripple to propagate through whatever medium it's passing.

The other type of wave is an electro-magnetic wave, in which a changing electric field generates a magnetic field at right angles to it, and this changing magnetic field generates another electric field at right angles to it.  (I don't remember the details of this too well, but it's something like that.)  These fields then propagate through space, one after the other, until something blocks them or absorbs their energy.

The thing is, one of these waves depends on interactions between different particles of a particular medium, and the other depends on energy fields kind of co-propagating each other through empty space.  But is space really empty, or is there some 'fabric' to it that we simply can't detect?  I chose the word 'fabric' here because people often talk about the 'fabric' of the space-time continuum, so this isn't really a new concept, but, to me at least, this is a new way of understanding the concept, and linking it to real-world experiences, or corroborating an idea that, in my mind at least, is just a theory.

If you think about it, if two phenomenon that appear to be different behave in such similar ways, then there's a good chance that they are related at some fundamental level, so this whole idea is interesting to me in that it can help support the theory that there is some kind of "medium" to the universe.

There's actually a third type of wave, the kind you get wave a piece of rope up and down.  This type of wave is similar to the sound wave in that it's propagating through a medium, but it's different in that, with water or air, the atoms are pushed in the direction that the wave is traveling, but with the rope, the particles (this time they're molecules) are being pulled in the opposite direction that the wave is traveling, and then the attractive forces between the molecules are pulling the adjacent molecules along with them.

However, when you think about it, even in the case of the sound wave, the atoms have a kind of attractive force as well in that something has to be forcing the atoms close enough together so that when they move, they immediately cause the atoms next to them to want to move as well.  That force is gravity.  It isn't really an attractive force because it doesn't come from the atoms themselves, but it serves the same purpose.  Without gravity, you wouldn't be able to have sound waves (at least not in a liquid or gas) because the particles would just disperse so that the movement of one wouldn't affect the movements of the others.

So what you really have, in both the sound through air or water scenario, and the rippling of a rope scenario, is particles that want to keep a certain distance from each other, a disturbance that cause some of these particles to move, and then a readjustment to get the particles back to the same distance.

If you apply this basic concept to the electro-magnetic waves, then what you have is some kind of medium that gets disturbed and then readjusts.  It may not necessarily be made of discreet particles.  I'm trying to picture it as some kind of continuous medium, like a rubber sheet or something, but that's not quite working.  If you try to disturb a particular position in a rubber sheet, it will always get pulled back to its original position, whereas, in the case of a light wave, this is moving in a particular direction along a very narrow path.  Particles can move laterally relative to each other without disturbing them, and it seems like something like that is necessary for light waves to act the way they do.

Anyway, I'm reaching the end of my knowledge here, so maybe someone else can provide some details to help keep this line of thought moving forward.

Thanks for reading (if you got this far).

-LeRoy