I've recently learned about EM waves. One thing I find hard to really get, is how the E and B fields are constantly "generating" each other. I think maybe the key for this is in the following equations, obtained from Maxwell’s equations in vacuum : (source: http://www.google.fr/url?sa=t&rct=j...MlmMOOV7U950u4mFg&sig2=-UeffQGg1JTyJw4Rra8Qlw) Here we see that: - a spacial changing E field creates a time changing B field - a time changing E field creates a spacial changing B field Or is it the other way around? - a spacial changing B field creates a time changing E field - a time changing B field creates a spacial changing E field Or...is it both? I can guess that both statements are actually true. But isn't this a kind of weird circular statement to say? One thing A creates another thing B but in the same time it is the B thing that makes the A thing. I find it a difficult concept. Usually in life, B is a consequence of A, or A is a consequence of B. Here it is like A and B are both consequence of each other. Or maybe I am misunderstanding the principle of a self-sustaining wave. Anybody would have some suggestion of explanation about this phenomenon? Do other people find it hard to understand?