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Relativistic electromagnetism
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Magnetism as a relativistic effect of electricity.
Magnetic force can be seen as the relativistic effect of electric force between moving charges: a wire carrying current has length-contracted charge densities in another frame. E and B mix under boosts.
A neutral wire looks charged to a moving charge.
Maxwell's equations are already relativistic.
In more detail
Relativity shows that the magnetic field of a moving charge is a consequence of electric fields seen in a moving frame. Electricity and magnetism are different aspects of one electromagnetic field.
Real-world uses
- Relativistic electromagnetism explains the magnetic forces on moving charges.
- It is a unifying principle in electromagnetic theory.
- Physicists show that the magnetic force on a moving charge can be derived from the electric force in a moving frame.
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Frequently asked questions
Is magnetism a relativistic effect?
Yes, magnetic fields arise from the relative motion of charges in different frames.
What does this unify?
Electric and magnetic fields combine into a single field tensor.
So is magnetism just electricity seen from another frame?
In a sense yes. Relativity shows that electric and magnetic fields are two aspects of one electromagnetic field.
Related topics in Relativity
Relativistic collisions · Particle accelerators and relativity · Mass–energy in nuclear reactions · Tachyons · Equivalence principle · Gravitational time dilation