# Magnet near a magnetic black hole

1. Mar 31, 2008

### rsr_life

Magnet near a "magnetic" black hole

Hi,

If I were to bring a magnet (just 1 mm long) close to a hypothetical "magnetic" black hole - something that has such an incredibly high permeability that it draws all the magnetic field lines from the magnet's pole toward it - and if this latter object were to extend several miles long and terminate abruptly and assuming no other object nearby, will the magnetic field still terminate at the other pole of the original magnet? (Before you say "Yes, the divergence law", consider the thought experiment below).

(I started looking at this at the micro level where there is no clear "north" pole and things aren't too clear to me.) I then assumed, at the simplest level, an electron (just 1) moving along a circular wire (copper atoms strung in line). When it moves, it "creates" a magnetic field around the wire at that point. If the magnetic black hole were placed near this wire, such that the field line(s?) at that point had to go through the black hole, would the field line still complete the loop?

How fundamental is Maxwell's law? Does it work all the way down to this level? I know that the differential form of Maxwell's law doesn't hold if there are other magnetic material near the original source (interface conditions). Where else do Maxwell's laws break down?

How does the field line "know" after miles of the black hole, the path that completes the loop? In other words, where is the information "kept". What happens if the second black hole (with the wire-electron example) extends to infinity (say, like a real "gravity" black hole, that's just really tiny)?

Also, for people familiar with EM at the quantum level, magnetic field lines aren't really "lines" right? Isn't the magnetic field more like the gravitational field, if analogies go all the way, in terms of some kind of curvature of space or something equivalent?

I'm not very clear if the assumptions I'm making are right. Sometimes the assumptions themselves are wrong at some basic level- they don't apply at the micro-scale, making the entire problem paradoxical.