7 HN users recommended this explainer7 months2014–2024score 7
Years with an HN recommendation, 2007–2026
HN commenters recommend it as a short, clear explanation of why moving charges create magnetic fields.
Veritasium explains magnetism as a consequence of special relativity. Length contraction of moving charges makes a current in a wire attract or repel a nearby moving charge.
“if you are curious why a moving charge creates a magnetic field watch this Veritasium video” (HN, 2021)
Here's a video explainer: [this video] Magnetism affects moving charges, but not stationary charges. A magnetic field in your reference frame is really just an electric field in the moving charge's reference frame.
Video explainer on magnetic fields across reference frames.
Magnetism is a side effect of special relativity: moving charges have length contraction (depending on frame of reference) which makes them appear more/less dense and therefore an attractive/repulsive force. Veritasium on YouTube made a much better explanation: [this video]
Much better explanation of magnetism as a relativity side effect.
Wow, this is the first time I have understood why nothing can go faster than the speed of light and why time dilation is a thing. A very easy to read article, give it a try. Also if you are curious why a moving charge creates a magnetic field watch this Veritasium video: [this video]
Explains why a moving charge creates a magnetic field.
Sort of, electricity and magnetism are two sides of the same coin, electromagnetism, so it's waves in the electromagnetic field with the wire acting as a wave guide. (as far as I understand) Veritasium has a video that goes over this. It was pretty controversial at release but it gives a good overview. [link] And why magnets work due to relativity [this video]
I think what GP meant is that (from one viewpoint) magnetism is an emergent property of the electric field and relativity. Here is a simple explanation: [this video]
Simple explanation of magnetism as emergent from electric field and relativity.
Another fun fact: Magnetic fields are a consequence of relativity and length contraction of electric fields. [link] This video also talks about it: [this video]
Video also explains magnetism as a relativistic effect.
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