Is there anything left to discover in electromagnetism? Are there any mysteries regarding electromagnetism?

[martillo]

Quote

Is there anything left to discover in electromagnetism? Are there any mysteries regarding electromagnetism?

Yes. To explain why or how the force between two magnets varies with exponent four in distance as determined in the following experiment:

"Force between two magnets as a function of distance"

 

[Markus Hanke]

1 hour ago, martillo said:

Yes. To explain why or how the force between two magnets varies with exponent four in distance as determined in the following experiment:

"Force between two magnets as a function of distance"

 

This force is the result of dipole-dipole interaction, so the total force between two macroscopic magnets will depend on how these dipoles are spatially distributed. In other words - it depends on the shape, location, and orientation of the magnets. For two single, point-like dipoles, the force indeed falls off with the 4th power of distance; but for other types of dipole distributions the force law will be more complex:

https://en.m.wikipedia.org/wiki/Force_between_magnets

This is not a new insight, since it directly derives from Maxwell’s laws.

[studiot]

9 minutes ago, neuerwind said:

No, they are. Vector algebra stipulates that we analyze rotary motion by projecting it on flat surfaces. On the contranry, the quaternion is a perfect mathematical representation of a rotating body per se.

Can you rephrase this please?

I can't figure out what you are trying to say.

3 hours ago, Markus Hanke said:

This force is the result of dipole-dipole interaction, so the total force between two macroscopic magnets will depend on how these dipoles are spatially distributed. In other words - it depends on the shape, location, and orientation of the magnets. For two single, point-like dipoles, the force indeed falls off with the 4th power of distance; but for other types of dipole distributions the force law will be more complex:

https://en.m.wikipedia.org/wiki/Force_between_magnets

This is not a new insight, since it directly derives from Maxwell’s laws.

 

Note that there are also quadrupoles and higher types to consider.

This is also the case with electrostatic effects.

[swansont]

!

Moderator Note

Hijack has been split to the trash. Discuss the OP's question, without introducing pet theories, please. (ignore anything to for from neuerwind remaining in the discussion)

 

[Markus Hanke]

21 hours ago, studiot said:

Note that there are also quadrupoles and higher types to consider.

This is also the case with electrostatic effects.

Very true, thanks for the reminder!

[Enthalpy]

How fast the interactions propagate may still be an open question.

I have still to think more at it, but when charges are near to an other and accelerate slowly, you can't use potentials retarded by x/c to compute the interaction. Just like the Earth-Moon interaction is much more instantaneous than delayed, as is known since the 19^th century.

At least common "knowledge" of electromagnetism is wrong here. How complete the understanding by experts is, I can't tell.

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Whether an alternating current by dielectric polarisation radiates a wave, I feel it safe qualitatively. The "1" part of permittivity, equal to vacuum permittivity, does not radiate. The rest, or electric susceptibility, results from charge movement and radiates. And dielectric antennas serve in most cellular phones.

But algebraically, with nice equations... That could be a remaining task, and it looks badly difficult. You know, write Maxwell's mess, and deduce logically what produces a radio wave or not.

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This relates directly with the computation of antennas. We evaluate the far field by computing the vector potential A from the conduction current I or J but we don't include the vacuum's polarisation current e*dE/dt. This fits experiments. Though, both are equivalent to create curl(B) in Maxwell's thingy. So why only the conduction current?

A direct application are vertical long-wave antennas. They get additional wires at the top to increase the capacitance there, so more current flows and the radiation increases. Though, this additional current returns to the ground through the added capacitance, and the return current compensates the additional conduction current. It works, why?

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Does the electrostatic interaction have inertia? When, and for who? For me that's very unclear, for experts I can't tell.
https://www.scienceforums.net/topic/85377-relativistic-corrections-to-hydrogen-like-atoms/?do=findComment&comment=990276

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The magnetic field of planets remains mysterious. For Earth we have a plausible model since the recent (!) VKS experiment
https://hal.archives-ouvertes.fr/hal-00492266/document
but for other planets it seems to fail.

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As far as I know, the coherer still needs an explanation
https://en.wikipedia.org/wiki/Coherer
it were about time, as the effect was observed in 1835, the devices entered service around 1880 and were abandoned a century ago. Possibly more material science than pure electromagnetism, but who knows, as we ignore the explanation.

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How does vacuum insulation (or rather the electrodes?) break down in a strong electric field? Probably not pure electromagnetism, but it would be very useful. Devices already use vacuum insulation despite we have no good models for it. Most people keep trying "field emission" again and again despite all evidence is against.