normal force

I was talking to somebody about how they teach high school science, in
particular the "normal force", and how only later I found out it was
actually electromagnetism. I was glad to find there wasn't really a
fifth mysterious force and it was one of the known four. But I was
thinking - what actually makes it equal to the gravitational force? I
mean why is it always just exactly mg? There are some obvious answers,
the first would be Newton's third law: every action has an equal and
opposite reaction. But why is the reaction with a different force? Or
rather, how does it work, how do two such different interactions
adjust to match each other? You might get a technical answer by writing
the Lagrangian with all the different potentials, gravitational and
electromagnetic, and minimizing that. But I still don't understand how
in fact it works. How do you get what seems to be an interaction
between two such different forces? If you want to talk in standard
model terms, how do you have virtual photons and gravitons talking to
each other so that they just even out?

I suppose the answer is just that each force separately tries to
minimize the total energy. But I have no idea how each of them knows
what the other is doing. Is the question clear? Can somebody explain
that?

.

Relevant Pages

  • Re: normal force
    ... > particular the "normal force", and how only later I found out it was ... > opposite reaction. ... > rather, how does it work, how do two such different interactions ... how do you have virtual photons and gravitons talking to ...
    (sci.physics.research)
  • Re: Latter Day MMX - discussion of LIGO
    ... |> Most direct radiation quanta is randomly polarized. ... |> transmission is via EM type of interactions. ... | That's one of the troubles with aether theories. ... gravitons and photons should be very similar. ...
    (sci.physics.relativity)
  • Re: gravitons
    ... Theese mysterious particles occure every now and then, ... > the gauge bosons of the theory "gravitons", and to know a few of their ... -- they must be QUANTUM OBJECTS. ... > TRANSFER (via the phase of the interactions). ...
    (sci.physics.relativity)