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Note: I have seen this question -> (What is a magnetic field) and would still like some clarification.

I have also seen https://www.youtube.com/watch?v=hFAOXdXZ5TM and https://www.youtube.com/watch?annotation_id=annotation_3566029675&feature=iv&src_vid=hFAOXdXZ5TM&v=1TKSfAkWWN0, and I believe I understand the implications of Special Relativity (on at least a basic level).

To help get at my confusion, I'll list off a few specific questions that might help orient the discussion.

The "electric field" is neither mass, nor energy- right? It's just a "force"? I'm not 100% sure what that means... does that just reduce down to "yeah, it's the exhibited behavior at a quantum level that we don't yet understand beyond that"- or is there some higher-level construction here?

Like, for example: is the vector field a big soup of moving electrons, the vector at that point referring to the average direction of electrons at that point? (So electrons would be constantly looping through this field, "bumping into"/"dragging around" anything with aligned/conflicting fields) Or is it some orientation of electrons/atoms at that point that has some net effect in rubbing against others? What is at that point that exerts the force there?

This could be paralleled to the "gravitational field" in that there isn't a "thing" at the place where the force is exerted- but I've heard that explained as a "bending of spacetime" which, while I won't pretend to fully grok is at least satisfactory in explaining how two things can interact with no interacting... thing... between them.

At the end of the day- it's all just not clicking for me. Any resources or explanation to help that click would be greatly appreciated!

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    $\begingroup$ Obligatory link to Feynman discussing magnets. $\endgroup$
    – ACuriousMind ♦
    Apr 22, 2016 at 16:30
  • $\begingroup$ @ACuriousMind Hah! I think I get where he's coming from, but still find the initial question reasonable. Why? "Well I need to ground an explanation in something and if you keep asking why to any grounding we'll never get anywhere". But I'm just hoping for maybe one level deeper than the supplied "they do have this effect". Then again, this Q is built on the assumption that "one level deeper" is within reasonable reach. If, in fact, it isn't- that the next step takes HEAPS of nuance and understanding, I guess I'm satisfied as is. But is that the case? Someone at least tell me this! $\endgroup$
    – Phildo
    Apr 22, 2016 at 16:55
  • $\begingroup$ My mistrust that "oh the next level is so severely complicated" stems from my previous lay-person learnings in Physics. "Things have a coefficient of friction". Wait what? How is "friction" an inherent-to-the-fundamental-universe concept? "Oh it's just a way to consider the average of all the little forces when two basically uniform objects rub against eachother". Oh! Well why didn't you just say that! <- That's the kind of aha moment I'm hoping for- that there's some slightly lower-level thing going on that would make it all make (reasonably more) sense. But maybe there isn't! $\endgroup$
    – Phildo
    Apr 22, 2016 at 17:00
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    $\begingroup$ "Like, for example: is the vector field a big soup of moving electrons," - Definitely not. If it was, your big soup of electrons would either need to be 1) a medium that was already there, that the EM wave is just passing through, or 2) emitted from the EM source, travelling along with the EM wave. We know it is not option (1) - google "aether" or "Michelson Morely experiment". We know it is not option (2), because the EM wave travels out from the source at the speed of light - electrons can't go that fast. $\endgroup$
    – mbeckish
    Apr 22, 2016 at 17:12

1 Answer 1

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A field is a field: not a force. A force describes the effect of the field on a specific "object" (see below) coupling to the field. In the current state of research, quantum fields (such as the photon field for electromagnetism, see Virtual photon description of B and E fields) are fundamental structures that cannot be decomposed or explained in simpler terms.

Now an "object" is itself made of interacting fields (see Which is more fundamental, Fields or Particles?). So your nicely put "how two things can interact with no interacting... thing... between them" confusion can be dissolved away by getting rid of the "thing" thing. There are only fields.

The one concept I see that is more fundamental than a field is spacetime, since a field is a distribution of values in spacetime. Spacetime is where the "between them" and "interacting" parts of the above quotation of yours take some meaning. But if spacetime is emergent (see How can space and time arise from nothing?), it is possible that this whole business of fields is even more intricated than it seems.

As you can see, looking for high-level understanding, as you ask, is first and foremost learning how concepts relate one to another, which involves studying physics in its own terms, where the relationships between the thinking, the math and the experiments have a very specific taste, different from mathematics or philosophy.

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  • $\begingroup$ I like this answer, but I have one question - what about energy? Is energy fundamental? Does an increase or decrease in the value of a field at a given location mean that there is now more or less energy at that location? $\endgroup$
    – mbeckish
    Apr 22, 2016 at 17:32
  • $\begingroup$ Wonderful! Thank you for the clarification. I hadn't realized fields were considered "fundamental", and not an abstraction of something (at least, at the level of "moving electrons" or anything else similarly "macro"). $\endgroup$
    – Phildo
    Apr 22, 2016 at 17:45
  • $\begingroup$ @mbeckish. See What is energy? Short answer to your question: no, energy is not linked to any given field in that way. $\endgroup$
    – Stéphane Rollandin
    Apr 23, 2016 at 6:41

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