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How Special Relativity Makes Magnets Work

How Special Relativity Makes Magnets Work

Veritasium
7 HN recommenders · discussed 2014–2024
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About this video

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.

Why it appears in the archive

HN commenters recommend it as a short, clear explanation of why moving charges create magnetic fields.

AI-generated summary and labels from the source dataset; verify important details against the video. Source & credits.

From the Hacker News discussion

kull · 2014-08 · rec

Here some modern explanation of the phenomena: (I love the way they explain it) "How Special Relativity Makes Magnets Work" [VIDEO] .

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snarfy · 2020-02 · rec

That's right. Here is a pretty good video explaining magnetism as a relativistic effect of electrostatics - [VIDEO]

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rovolo · 2020-04 · rec

Here's a video explainer: [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.

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HPsquared · 2020-07 · rec

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: [VIDEO]

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programmer_dude · 2021-09 · rec

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: [VIDEO]

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lugoues · 2024-06 · rec

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 [VIDEO]

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amelius · 2024-08 · rec

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: [VIDEO]

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snarfy · 2014-11 · reference

Another fun fact: Magnetic fields are a consequence of relativity and length contraction of electric fields. [LINK] This video also talks about it: [VIDEO]

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