Originally posted by Eyesaw
Everyone at the time believed in an ether so I think it’s a good assumption to say that the whole Electromagnetic model was based on an ether as substrate.
That's not what I asked you. I asked you what substrate is
logically derivable from Maxwell's equations, not what the original formulators of the theory
believed about it.
I don’t think anyone before Einstein would have been crazy enough to think a wave can exist absence of a medium since waves are not the actual particle motion but the silhouette of their collective motion. A common illustration of wave motion is the people in a stadium who start standing up and down one by one- if you only have one person in the stadium, you can’t have wave motion.
Again, this presupposes that matter (or some substance)
must be involved in wave motion. Why can't EM waves simply be displacements in the
E and
B fields,
as Maxwell's equations themselves say they are?
I think you misunderstood the sentence. I’m saying there’s no way to reject the idea that some medium exists in which light is just the disturbance in the medium, like any normal wave, since one can always argue that the stuff consisting of the medium are too small to be detectable by current technology.
OK
For example, Dr. Tom Van Flandern proposes such a medium in the Meta Model which they called the Elysium. The medium you are speaking of here is total empty space of which there would exist no properties, which is entirely opposite to the ether medium Maxwell and all those who developed the Maxwell equations envisioned. So if you are going to derive Maxwell’s equations based on the ability of light as a wave that travels without a medium, you have to show that this is possible in the first place. But as mentioned before, you can’t rule out the possibility of a medium consisting of particles too tiny to be detected which could explain the wave motion so you this introduction of a radically new concept- that of a wave existing without a medium- becomes unnecessary.
I don't "rule out" the ether. I even acknowledge that SR doesn't rule it out. My position (which is the position of SR) is not that "the ether does not exist", but rather that "the ether is a superfluous concept that is not logically derivable from Maxwell's equations".
You are not adding an assumption when considering an ether necessary for wave motion.
Actually, you are, since the Maxwell theory does not require an ether. The postulates of SR are not a new model of EM wave propagation, they are simply comments on the old theory, namely that the speed of light is source-independent (which has been experimentally verified) and that the laws of physics are the same for all inertial observers (ditto for that one).
Are you adding an assumption by saying that ocean waves need an ocean to exist?
Of course not. But you
are adding an assumption when you say that EM waves require anything more than an EM field to exist.
If so, you should take that up with Mother Nature. While you’re at it, you should file the complaint also that gravity is unnecessary since we already have attractive motion in Electromagnetism.
Gravity is
observed. The same cannot be said of the ether.
If a wave model already exists that can explain EM radiation, the introduction of a new model for waves just to accommodate light becomes uneconomical, especially since it contradicts the mountains of evidence for normal wave behaviour in sound and other waves.
I am not proposing a new wave model. My contention is that the Maxwellian wave model
does not include an ether.
Well, because in every particle we know of when momentum is transferred, they gain velocity. Since SR rejected the ether and yet assumes source independency of light, both of which are “assumptions” which totally contradicted all evidence of wave and particle behavior prior to Einstein, the one proposing such radical ideas should provide some clear evidence such contradictions are necessary to explain the behavior of light. Or develop a mathematical model to demonstrate this special behavior. All Einstein seemed to have done in SR is point out that Maxwell’s equations predict a constant speed c for EM waves propagating in a uniformly dense ether. But since he got rid of the ether, he loses his right to use Maxwell's equations for his theories.
Since Einstein, the source independence of the speed of light has been observed. Einstein also gave persuasive theoretical arguments on why this
should be so. Also, as I said before, SR does not reject the ether. It simply does not need it, which is why
the ether is "uneconomical".
