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How Special Relativity Makes Magnets Work

Veritasium · explainer · Watch on YouTube

Fundamental physics

What it is

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 Hacker News recommends it

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

  • 7 people recommended it
  • 7 different months
  • 0 strong recommendations
  • first 2014, last 2024

What HN commenters said

  1. “I love the way they explain it”

    Modern explanation of magnetism via special relativity.

    kull, 2014-08 · Recommendation · in “How Magnets Produce Electricity (1954) [video]”

  2. “Here is a pretty good video explaining magnetism as a relativistic effect of electrostatics”

    Explains magnetism as a relativistic effect of electrostatics.

    snarfy, 2020-02 · Recommendation · in “Ultimate Electronics”

  3. “Here's a video explainer”

    Video explainer on magnetic fields across reference frames.

    rovolo, 2020-04 · Recommendation · in “Why is Maxwell's theory so hard to understand? (2007) [pdf]”

  4. “Veritasium on YouTube made a much better explanation”

    Much better explanation of magnetism as a relativity side effect.

    HPsquared, 2020-07 · Recommendation · in “Bohr–van Leeuwen theorem – magnetism in solids is a quantum mechanical effect”

  5. “if you are curious why a moving charge creates a magnetic field watch this Veritasium video”

    Explains why a moving charge creates a magnetic field.

    programmer_dude, 2021-09 · Recommendation · in “Why can’t I go faster than the speed of light?”

  6. “And why magnets work due to relativity”

    Explains why magnets work due to relativity.

    lugoues, 2024-06 · Recommendation · in “Why does current flow the opposite way from the electrons?”

  7. “Here is a simple explanation”

    Simple explanation of magnetism as emergent from electric field and relativity.

    amelius, 2024-08 · Recommendation · in “NASA Discovers a Long-Sought Global Electric Field on Earth”

Excerpts from Hacker News comments, linked to the originals. Summaries and labels were written by a language model from those comments.

Topics: special relativity, magnetism, length contraction, electromagnetism, veritasium

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