I’ve searched the topic through multiple pop science sources, but I still cannot see to grasp what magnetism actually is, and what it does.
Some basic answers talk about magnetism being the stuff that makes magnet works, that moving charges cause it, and that in reality it’s just special relativity making electricity act like what we call magnetism. They all use the same old example of a wire with moving charges in front of one with static charges, and imply that magnetism is just a fictitious force, that charge is the real stuff, that magnets are when electrons move inside atoms. All of it sounds nice and simple, except for this little thing called spin that gets throw aside as a minor detail…
Then there is the other main explanation, the one that talk about magnetism as having to do with spin, but never explain what exactly it does different from regular electric charge, or why electric charges in movement cause it, it just does. This explanation tells how it is a field, how it is interconnected with the electric field and changes in one make changes in other, and how light is a wave in both. Magnetism just is, it’s just present and all electrons are magnets but that explain little about what it does, how it is different from charge. Does it not attract and repel?
So TL:DR, what is magnetism anyways, what does it do to electrons and other particles? Does it pushes and pulls, or does it do something else?
In: 1
Electromagnetism, as a whole, is a force. Magnetism is the rotational portion of the force. One way to see this is to imagine a perfectly round, charged sphere, that is spinning, and near it a test particle of opposite charge. Then electric force is the component that pull the test particle toward the sphere, and magnetic force is the component that drag the test particle along the direction of rotation.
However, such separations are different between different observers. Principle of relativity say that between 2 frame of references that are in constant motion with respect to each other, then the law of physics are unchanged. So there are no special observers, nobody can claim to be the true one that can see real physics. But different observers will see different thing: what someone see as rotation, someone else might not see it as such. So the separations between electric and magnetic force is subjective, internal to each observer. As a whole, both force should be considered the same.
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