# Magnets **URL:** \ **Category:** Factual Questions\ **Created:** [December 2, 2015, 8:33pm UTC](https://boards.straightdope.com/t/magnets/739249 "2015-12-02T20:33:31Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Leonard33](https://avatars.discourse-cdn.com/v4/letter/l/e8c25b/32.png) [@Leonard33](https://boards.straightdope.com/u/Leonard33)\ **Post date:** [December 2, 2015, 8:33pm UTC](https://boards.straightdope.com/t/magnets/739249/1 "2015-12-02T20:33:31Z")
I had a random thought while looking through recent posts. I wondered if it was possible to have a magnet with only one pole. Like just the entire magnet has just the north pole or just the south. Has something like this ever happened? It it possible to create something of this nature? Thanks ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 2, 2015, 8:40pm UTC](https://boards.straightdope.com/t/magnets/739249/2 "2015-12-02T20:40:50Z")
It’s called a magnetic monopole. Wikipedia has an article for it: > **[Magnetic monopole](https://en.wikipedia.org/wiki/Magnetic_monopole)** > > In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net north or south "magnetic charge". Modern interest in the concept stems from particle theories, notably the grand unified and superstring theories, which predict their existence.\[full citation needed\] The known elementary particles that have electric charge are electr Magnetism... Physicists managed to create a Dirac monopole last year. > **[Physicists Finally Made The One-Poled Magnet They've Been Missing For 80 Years](https://www.businessinsider.com/physicists-create-magnetic-monopole-2014-1)** > > Their results confirm a fundamental idea in modern physics ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 2, 2015, 9:21pm UTC](https://boards.straightdope.com/t/magnets/739249/3 "2015-12-02T21:21:44Z")
> [@engineer\_comp\_geek](#): > > It’s called a magnetic monopole. Wikipedia has an article for it: > [Magnetic monopole - Wikipedia](https://en.wikipedia.org/wiki/Magnetic_monopole) > > Physicists managed to create a Dirac monopole last year. > [Physicists Create Magnetic Monopole - Business Insider](http://www.businessinsider.com/physicists-create-magnetic-monopole-2014-1) You’re sure someone wasn’t just turning the electric can opener on and off? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [December 2, 2015, 9:48pm UTC](https://boards.straightdope.com/t/magnets/739249/4 "2015-12-02T21:48:45Z")
[Nature article abstract with pretty pictures](http://www.nature.com/nature/journal/v505/n7485/full/nature12954.html). ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [December 2, 2015, 9:50pm UTC](https://boards.straightdope.com/t/magnets/739249/5 "2015-12-02T21:50:36Z")
> [@Joey\_P](#): > > You’re sure someone wasn’t just turning the electric can opener on and off? Well, it was that or murder… ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 2, 2015, 10:11pm UTC](https://boards.straightdope.com/t/magnets/739249/6 "2015-12-02T22:11:53Z")
I like the way Chronos put it in [this](http://boards.straightdope.com/sdmb/showthread.php?t=594268) thread “Magnetic monopoles certainly exist. But the number of them in the Universe might be very small, possibly zero” ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 2, 2015, 10:58pm UTC](https://boards.straightdope.com/t/magnets/739249/7 "2015-12-02T22:58:54Z")
> [@](#): > > Quoth **engineer\_comp\_geek** : > > Physicists managed to create a Dirac monopole last year. That’s a terrible article. What the researchers created was not a monopole. It was a configuration of magnetic field that looks a lot like a monopole, if you pay no attention to the man behind the curtain. Without monopoles, magnetic field lines always form closed loops. If we did have a monopole, magnetic field lines would end on it. What those researchers did was take a bunch of ordinary closed-loop field lines, and bunched them together in a very small tube, so that _if you ignore the tube_, it looks like field lines ending at a point. But they’re not ending there; they’re just going into the tube. ---
**Author:** ![mcgato](https://avatars.discourse-cdn.com/v4/letter/m/ac8455/32.png) [@mcgato](https://boards.straightdope.com/u/mcgato)\ **Post date:** [December 3, 2015, 2:30pm UTC](https://boards.straightdope.com/t/magnets/739249/8 "2015-12-03T14:30:46Z")
As an undergrad, I worked on an experiment to find magnetic monopoles. We didn’t find any. In the early stages of setting up the detector, the first thing we detected was the garage door opening. [Here’s the abstract of the first paper published with our findings.](http://journals.aps.org/prd/abstract/10.1103/PhysRevD.34.2637) Note that my work ended with my graduation, and the experiment continued for another year or two. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [December 3, 2015, 2:44pm UTC](https://boards.straightdope.com/t/magnets/739249/9 "2015-12-03T14:44:46Z")
What happens if you take a sphere of magnetic material and magnetize it so that the south pole is at the center, and the north pole is at the surface? The field lines exit the north pole everywhere on the surface of the sphere, but where do they go to get back to the south pole at the center of the sphere? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [December 3, 2015, 3:07pm UTC](https://boards.straightdope.com/t/magnets/739249/10 "2015-12-03T15:07:18Z")
> [@Machine\_Elf](#): > > What happens if you take a sphere of magnetic material and magnetize it so that the south pole is at the center, and the north pole is at the surface? The field lines exit the north pole everywhere on the surface of the sphere, but where do they go to get back to the south pole at the center of the sphere? How would you go about doing that? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [December 3, 2015, 3:12pm UTC](https://boards.straightdope.com/t/magnets/739249/11 "2015-12-03T15:12:32Z")
> [@beowulff](#): > > How would you go about doing that? I think you could get something like that with a Hallback array. There are cylindrical magnets with one pole in the center of the cylinder and the other on the perimeter. My own quest, I’m looking for a magnet with three poles. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 3, 2015, 3:15pm UTC](https://boards.straightdope.com/t/magnets/739249/12 "2015-12-03T15:15:04Z")
> [@TriPolar](#): > > I think you could get something like that with a Hallback array. There are cylindrical magnets with one pole in the center of the cylinder and the other on the perimeter. > > My own quest, I’m looking for a magnet with three poles. [and joey suddenly realizes that SDMB member TriPolar is Tri-Polar, not tripolar (TRIPolar)] ETA [and joey just realized who he quoted] ---
**Author:** ![swampspruce](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/swampspruce/32/261_2.png) [@swampspruce](https://boards.straightdope.com/u/swampspruce)\ **Post date:** [December 3, 2015, 3:15pm UTC](https://boards.straightdope.com/t/magnets/739249/13 "2015-12-03T15:15:09Z")
Take a series of bar magnets that grow increasingly smaller in size with each iteration and point all the S poles to the centre until you have a complete sphere. Sure it will want to fly apart and be massively unstable but it is an interesting thought experiment. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [December 3, 2015, 4:15pm UTC](https://boards.straightdope.com/t/magnets/739249/14 "2015-12-03T16:15:06Z")
> [@swampspruce](#): > > Take a series of bar magnets that grow increasingly smaller in size with each iteration and point all the S poles to the centre until you have a complete sphere. This. You approach it the same way you would a calculus integration problem, by defining a discrete element and then shrinking that element down to infinitesimal size. In this case, the discrete element is a bar magnet that tapers to a point at the south pole, and you put a bunch of them together to form a rough approximation of a sphere. As you make the bar magnets narrower and add more of them to complete a better and better approximation of the same sphere, the taper angle of each magnet becomes very small so that the south-pole field lines aren’t all busting out of the conical surface of each magnet element. > [@TriPolar](#): > > I think you could get something like that with a Hallback array. There are cylindrical magnets with one pole in the center of the cylinder and the other on the perimeter. Now imagine the ends of this cylinder circle around to join each other, forming a toroid, and you’ve got a similar situation: how do the lines leaving the north pole and the lines leaving the south pole find each other? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 3, 2015, 7:40pm UTC](https://boards.straightdope.com/t/magnets/739249/15 "2015-12-03T19:40:44Z")
You’re assuming that the lines ever leave the outside. They won’t. Or rather, they will, but only to the extent that your spherical arrangement is imperfect, and will form a sort of very short-range magnetic “fuzz” near the surface. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [December 3, 2015, 8:04pm UTC](https://boards.straightdope.com/t/magnets/739249/16 "2015-12-03T20:04:34Z")
> [@Chronos](#): > > You’re assuming that the lines ever leave the outside. They won’t. Why not? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [December 3, 2015, 9:05pm UTC](https://boards.straightdope.com/t/magnets/739249/17 "2015-12-03T21:05:27Z")
There are [Hallbach Spheres](https://en.wikipedia.org/wiki/Halbach_array#Halbach_spheres), but not what I was expecting according to [figure 4 in this reference](http://www.magnetocaloric.com/Code/pub01.htm). ---
**Author:** ![MikeS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MikeS](https://boards.straightdope.com/u/MikeS)\ **Post date:** [December 3, 2015, 9:52pm UTC](https://boards.straightdope.com/t/magnets/739249/18 "2015-12-03T21:52:55Z")
> [@Machine\_Elf](#): > > Now imagine the ends of this cylinder circle around to join each other, forming a toroid, and you’ve got a similar situation: how do the lines leaving the north pole and the lines leaving the south pole find each other? > [@Chronos](#): > > You’re assuming that the lines ever leave the outside. They won’t. Or rather, they will, but only to the extent that your spherical arrangement is imperfect, and will form a sort of very short-range magnetic “fuzz” near the surface. To elaborate on **Chronos** ’s answer: a general statement concerning the magnetic field is that the net number of magnetic field lines that come out of any surface in space is proportional to the number of magnetic poles inside that surface (north counting as positive, south as negative). Imagine a spherical surface just outside the outer surface of the magnet sphere (like a soap bubble surrounding it.) Since there are the same number of north and south poles inside this surface (inner and outer surfaces combined), then the same number of field lines must enter the surface as exit it, for a net of zero field lines exiting the surface. If you have perfect spherical symmetry, then if there’s a field line exiting the sphere at one point, then there must be a field line exiting at all points. This is a contradiction. Thus, there are no field lines exiting the sphere. (For those who know what I’m talking about, I’m really talking about the auxiliary field H in this explanation, rather than the magnetic field B. But they’re proportional to each other anywhere outside of magnetized matter.) ---
**Author:** ![Leonard33](https://avatars.discourse-cdn.com/v4/letter/l/e8c25b/32.png) [@Leonard33](https://boards.straightdope.com/u/Leonard33)\ **Post date:** [December 8, 2015, 12:39am UTC](https://boards.straightdope.com/t/magnets/739249/19 "2015-12-08T00:39:23Z")
Thanks this has certainly giving me something to chew on. Have a good day. ---
**Author:** ![Andy\_L](https://avatars.discourse-cdn.com/v4/letter/a/c67d28/32.png) [@Andy\_L](https://boards.straightdope.com/u/Andy_L)\ **Post date:** [December 8, 2015, 1:00am UTC](https://boards.straightdope.com/t/magnets/739249/20 "2015-12-08T01:00:34Z")
> [@Chronos](#): > > That’s a terrible article. What the researchers created was not a monopole. It was a configuration of magnetic field that looks a lot like a monopole, if you pay no attention to the man behind the curtain. Without monopoles, magnetic field lines always form closed loops. If we did have a monopole, magnetic field lines would end on it. What those researchers did was take a bunch of ordinary closed-loop field lines, and bunched them together in a very small tube, so that _if you ignore the tube_, it looks like field lines ending at a point. But they’re not ending there; they’re just going into the tube. Yeah, I’ve been seeing versions of that article for several years now, and each time, I end up having to explain the above distinction. [Next page](https://boards.straightdope.com/t/magnets/739249.md?page=2)