# How do magnetic fields work? **URL:** \ **Category:** Factual Questions\ **Created:** [April 8, 2003, 12:41pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294 "2003-04-08T12:41:46Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![starman](https://avatars.discourse-cdn.com/v4/letter/s/8c91f0/32.png) [@starman](https://boards.straightdope.com/u/starman)\ **Post date:** [April 8, 2003, 12:41pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/1 "2003-04-08T12:41:46Z")
How do magnets affect one another? For instance, if you place two bar magnets in a hard vaccum, will they attract/repel each other, and if so, how is the magnetic force transmitted? (by wave, particle, whatever…) Also, what is responsible for the magnetic field of the sun? -Oli ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [April 8, 2003, 1:02pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/2 "2003-04-08T13:02:38Z")
Until somebody comes along who knows what they are taliking about, read this: [http://www.straightdope.com/mailbag/mlightwaveparticle.html](http://www.straightdope.com/mailbag/mlightwaveparticle.html) It will at least give you some background info on Electromagnatism before any specific discussion begins… Great read! ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 8, 2003, 1:49pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/3 "2003-04-08T13:49:09Z")
Physicists, please correct me if I’m wrong here, but I believe the following are true: 1. A _static_ magnetic field is produced by one or more _moving_ charges. These charges are moving at a (more or less) _constant_ speed. 2. A _changing_ magnetic field can be produced two ways: a) By moving charges, wherein their speed is _changing_, b) A changing _electric_ field. The latter is how a magnetic field is sustained in an electromagnetic field (e.g. radio wave). ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [April 8, 2003, 3:21pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/4 "2003-04-08T15:21:41Z")
Coorect. In addition, static magnetic fields are also produced by unpaired or unbalanced electron spin, as in ferromagnetic materials. BTW, I believe the magnetic field produced by a moving charge is actually produced by its electric field (which is changing at each point). So for the OP, vacuum has nothing to do with it. AFAIK (and that’s not very far), the electromagnetic force is moderated by photons, but I’m not sure exactly how magnetic fields propagate in the latest theories. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [April 8, 2003, 3:28pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/5 "2003-04-08T15:28:51Z")
> [@](#): > > \*Originally posted by starman \* > \*\*How do magnets affect one another? For instance, if you place two bar magnets in a hard vaccum, will they attract/repel each other, and if so, how is the magnetic force transmitted? (by wave, particle, whatever…) > Also, what is responsible for the magnetic field of the sun? > -Oli \*\* 1. Two bar magnets will attract/repel each in a hard vacuum. 2. The magnetic force is one aspect of the electromagnetic force. See the Straight Dope article linked previously by **kevsnyde** for more info. 3. From [this website](http://science.nasa.gov/ssl/pad/solar/the_key.htm): > [@](#): > > Magnetism, or magnetic field, is produced on the Sun by the flow of electrically charged ions and electrons. Here’s another website about the Sun’s magnetic field: [http://solar.physics.montana.edu/YPOP/Spotlight/Magnetic/](http://solar.physics.montana.edu/YPOP/Spotlight/Magnetic/) ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 8, 2003, 3:58pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/6 "2003-04-08T15:58:59Z")
And from the master: [http://www.straightdope.com/classics/a3\_339.html](http://www.straightdope.com/classics/a3_339.html) ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 8, 2003, 7:40pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/7 "2003-04-08T19:40:58Z")
However, one of the questions in the OP hasn’t really been answered… as one of the fundamental forces of the universe, how does magnetism propagate in a vacuum? Gravity is regarded as curving space- does magnetism do something similar, or is it ‘moderated by photons’, or what? What is this action at a distance lark all about, eh? ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [April 8, 2003, 8:27pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/8 "2003-04-08T20:27:12Z")
Channeling **Chronos** … ---
**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:** [April 8, 2003, 9:38pm UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/9 "2003-04-08T21:38:36Z")
As summoned, I arrive… But I’m not sure what else to add. Magnetic fields are one component (or three components, or six, depending on how you count) of the electromagnetic field, and in fact, Special Relativity requires that both exist and be aspects of the same thing. Electromagnetic fields don’t need a medium, and they can be described in terms of virtual (or even real) photons. I will _not_ attempt to go into more detail on how virtual photons give you a field. As for explanations of the fundamental forces, a relativist will tell you that gravity is perfectly well-understood as curvature of spacetime, but it’s a mystery how the other forces fit in. A particle physicist will tell you that electromagnetism and the nuclear forces are well-understood in terms of virtual force vector bosons, but that it’s a mystery how gravity fits in. It depends on what you’re looking for as an “explanation”. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [April 9, 2003, 6:31am UTC](https://boards.straightdope.com/t/how-do-magnetic-fields-work/167294/10 "2003-04-09T06:31:03Z")
Thank you, now I know what to look for (in order to be baffled).