So my physics teacher assigned us an article about how special relativity causes magnetism in a wire with a current, even with the low drift velocities of electrons in a current.
It seemed that the basis of the article was that magnetism is just relativistic electricity, so I was wondering how a permanent magnet worked? It makes sense to me that a moving charged particle attracts unmoving particles of the opposite charge, but how do the orbits of electrons in a magnet cause it to have a magnetic field?
Magnetism – How Special Relativity Causes Magnetism
electricityelectromagnetismspecial-relativity
Best Answer
It is a mistake to think that special relativity (SR) causes magnetism. The article you're reading is arguing that
This statement is true, I admit it. But it's equally true that
In reality, electricity and magnetism are equally fundamental parts of physics. Special relativity unites electricity and magnetism into electromagnetism, in exactly the same way that it unites space and time into spacetime. Time does not cause space, space does not cause time, and SR causes neither space nor time. SR merely reveals the relatedness of space and time. Similarly, electricity does not cause magnetism, magnetism does not cause electricity, and SR causes neither electricity nor magnetism. SR merely reveals the relatedness of electricity and magnetism.
A lot of people come across (A) in their high school or intro college physics classes, and wind up misunderstanding it as the fundamental reason that magnetism exists. Why is that? And why do textbooks almost never point out (B)?
The reason is simply that nobody questions why electricity exists--electrical attraction and repulsion seem perfectly natural--whereas magnetism seems more mysterious. In other words, this pedagogical asymmetry between electricity and magnetism has nothing to do with physics, and everything to do with our inborn preconceptions and intuitions.