Monopoles

[Welwynformed]

If I construct a tetrahedron with a magnet at the centre of each face (i.e. all norths out) and put it inside a cube with a magnet at the centre of each face (All norths in) and place that in the centre of a dodecahedron with the same set up (All norths out) such that each layer is able to freely rotate inside. Why don't I have a magnetic monopole and if I did would it have any use?

[Atheist]

Maybe you should be asking scientists, not AB people.

[jim360]

He could be asking both :)

[Atheist]

Jim360, do you have a view on this? Is a magnetic monopole something generally accepted as possible by the scientific community? Or is it akin to perpetual motion?

[Canary42]

I can't help I'm afraid. In order to educate myself I did look up Monopole in Wiki, but soon got left well behind in trying to understand it.

I got the impression that they are hypothetical only, and are still being sought.

[jim360]

Anyway, the answer is that you wouldn't have a monopole, because the arrangement you are imagining is inherently unstable, and the magnetic fields would soon arrange themselves so that the poles are at either end of the shapes, rather than on the outside and inside.

Put another way, rather than this complicated geometry, it's enough to check what the magnetic field configuration of a spherical magnet is. But in fact it turns out to be hemispherical, rather than radial.

This is something of a circular argument, since I'm making this statement based on the empirical fact that there are no magnetic monopoles. Even so, since this appears to be the case, it's reasonable to use that to justify why your arrangement wouldn't work. If monopoles do exist then they are exotic and can't be constructed using any physical means at our current disposal.

[jim360]

As to whether or not monopoles exist? I'm not sure, is the honest answer. There are, I think, certain nice reasons to argue that they maybe should. But they haven't been seen, and my guess is that we won't see them any time soon.

Separately, there are some exotic systems that exhibit monopole-like behaviour, but as far as I am aware this is only an analogy, and in any case only appears in complex systems that couldn't be constructed in the manner above.