# Homework Help: How would one describe the universe in which

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1. Aug 20, 2015

### rabidwolverine

there are no electromagnetic waves? All I know is that there is a modified version of the Maxwell equations (in differential form) for such a universe, such as (the arrows represent vector arrows):
→∇x →B = μ0 →j + μ0 ε0 ∂→B/∂t instead of having ∂E/dt in the last term (which would be the case for the normal universe; also the other Maxwell equations in differential form stay the same for the real universe and this EMW-less universe, apparently).

How would one derive the Maxwell's equations for this imaginary universe that has no electromagnet waves, in their simplest form? What are the consequences of such an EMW-less universe, i.e. what do no EMW's describe/imply for the universe and the bodies within it? Also, based on some google searches I realized that apparently sine and cosine can not be solutions of these equations?

Finally, I would like to add that this topic is well beyond scope of our physics class's syllabus but was just given to us as an additional guided reading but I do not understand how one can answer this abstract yet math-dependent question. Therefore, I would appreciate any detailed input. Thank you.

2. Aug 20, 2015

### Jeff Rosenbury

I've posted the answer in that other universe. Oh wait, you can't read it without light.

Nearly everything we observe is observed through EM waves. The atoms we touch are largely empty except for their electrical charges. The light we see is an EM wave. Sound is a compression wave compressing gasses through their electric charge. About the only common effect that isn't EM related is gravity, and even there, the electric charge of the atoms in the ground keeps us from falling to the center of the earth.

BTW, I recently learned Maxwell's equations can be derived from relativity, given that charges exist. They can be derived from Quantum theory similarly.

The standard model isn't a bunch of isolated facts. It all fits together. Changing one part affects (and largely negates) other parts.