# A mechanical 'monopole'?

1. Jun 24, 2011

### danR

I cut some magnets into buckeyball-faced polyhedra and bond the pieces together so that all joints are completely flush. Assume the joints are perfectly planar-flush, and bonded with a monolayer of something with a small molecular size. Or better yet, the thing is assembled in a vacuum and the unoxidized faces bond together directly

The pieces all have with the same polarity outward.

What do I have?

Edit:The material is samarium-cobalt with very high coercivity. Just to make isolated local domains a wee bit harder to posit as the outcome.

Last edited: Jun 24, 2011
2. Jun 24, 2011

Staff Emeritus
You haven't actually done this, because if you had you would notice that what you built is fairly non-magnetic.

Draw the field lines of the pieces. Where do the field lines go when you glue them together?

3. Jun 24, 2011

### danR

1. Of course I haven't done it. It's a gedankenexperiment.

2. You tell me. It's high coercivity samarium-cobalt. Those lines will not be so easily dissuaded by mere assembly. Assembly can proceed several ways, but if I start by joining one piece to another, I have a somewhat wider single (slightly curved) plate-magnet with a north on one side of the plate and south on the other and the lines of force curving fairly normally around the entire assembly.

Continue from there, step by step. Eventually the pieces and the electrons and the lines of force start to realize: 'Hey, we've been duped!'

But it's too late. We have a ball with a North outside, and a South trapped inside.

Edit: I assume you will answer we have a rather warm metal ball with no magnetism whatever.

4. Jun 25, 2011

### Blibbler

Or a Dirac pipe will form to let the flux flow from the North pole to the South.

5. Jun 25, 2011

### danR

I didn't know Dirac smoked a pipe. You're thinking of a Bohr pipe?

C'mon, I want a serious discussion! If we assemble the sphere to the point of one segment missing, then we can picture the outside flux all curving around to inside the remaining hole. No problem.

What happens when we bond in the last piece? The field intensity is almost as high at the edges of each segment as its middle, the coercivity is high. Obviously we'll need a vise to ram it in, and perhaps the whole thing must be wrapped in duct tape. That would obviate the need for glue.

Since magnetic monopoles are not forbidden, and appear to answer much, I see no theoretical reason why the final assembly would not be a magnetic monopole. Does anyone say a monopole has to small? That it must be a single particle?