This has been intriguing me since I bought some of the new rare earth magnets recently (niobium I think) and was highly impressed by how powerful they are. I did some online looking, but none of the sites I’ve seen actually talk about what magnetism is - they discuss field lines and electromagnetism and light and all that, but what I’m looking for is some sort of explanation of how one piece of metal can exert an invisible attractive or repulsive force on another at a distance. What is actually happening when I feel a magnet pulling out of my fingers, or being forced away from another one? Are there force carrying particles being exchanged? Is the fabric of space/time being warped? Are tiny angels flitting back and forth??
I kinda felt like reading about magnetism.
Hoping some doper would hit us with some amazing knowledge about Magnets.
I found this ~
http://www.wondermagnet.com/dev/magfaq.html
:rolleyes:
AFAIK, no one knows what magnetism is . It’s a property of certain molecules, but as to what gives something a magnetic moment or dipole is unknown. It’s kind of like the concept of nuclear spin - I’m not going to explain it, but it’s a property that atomic nucleii have, that causes certain things to occur, and it’s kind of like a “spin”, but at the same time it really isn’t, and no one knows what makes it spin-like and not spin-like. And thus far, no one knows how to possibly approach the problem to get an answer out of it. It’s just that magnetism, and spin, are things that simply exist, and we can do a lot of work showing that it exists, and we can mathematically draw this stuff out and predict what will occur in certain situations, but why does it work? Dunno.
I’m kind of redundant, aren’t I? But unless I (and my Quantum Chemistry prof) haven’t heard of some breakthrough research lately, then the answer is still unknown.
Magnetism is thought to be very similar to the electrostatic attraction and repulsion which keeps atoms together and keeps them bonded into solids. To explain magnetism, first explain why atoms don’t just fall apart into separate electrons and protons. (I.E. explain why rubbing a balloon on your arm hair will let the balloon attract your arm hair across empty space.)
Electric fields and magnetic fields are thought to be made of clouds of virtual photons being exchanged between the separate objects. A magnetic field or an electric field is sort of like a light wave or radio wave which is flowing in a tight loop and is attached to matter particles.
We should NOT imagine that magnetism is abnormal, since all everyday objects are really just clouds of tiny dots with large spaces between (and physical objects can never “touch” each other.) Everyday objects “touch” each other across empty space just like magnets do. It’s just that the empty space is normally very small. Magnets are just LARGE, and they create effects which are perfectly normal for atoms, but which are usually too small to see. In a way, a magnet is a “giant atom” and has many of an atom’s weird characteristics.
Physics version: magnetic fields are just distorted electrostatic fields caused by electrons and protons. Where magnetic fields are concerned the e-fields of the electrons and protons have been distorted or “compressed” because they are moving. They follow Einstein’s Relativity. An everyday object would only look squashed when travelling at nearly the speed of light, but the Relativity-squashing of electrostatic fields is important even if they move very slowly.
Magnetic fields seem as if they’re separate from “static electric” fields because magnetic fields usually DON’T appear as distortions of strong electrostatic fields. Instead, the intense electrostatic fields from the positive and negative charges in the magnet get cancelled out, and ONLY the distortion is left behind.
If you move some electrons along, their fields get distorted. If you place some unmoving electrons near some protons, the charges cancel out and there are no fields at a distance. But if you then move the electrons PAST the protons, the electrons’ e-fields will relativistically distort, but the opposite e-fields from the protons will not. Subtract the electrons’ fields from the protons’ fields and, whenever charges are moving, the “distortion” will be left behind.
That’s a fancy way of saying that magnetic fields are caused by electric current. The invisible field which surrounds a bar magnet is created by the electrons in the iron atoms. They’re spinning. Spinning charges are an electrical current, same as when the charges were flowing in a circle.