Researchers have uncovered friction without contact—driven entirely by magnetic interactions. As two magnetic layers slide, their internal forces compete, causing constant rearrangements that dramatically increase resistance at certain distances. This creates a surprising peak in friction instead of a steady rise, breaking a long-standing physics law.
  • PhoenixzEnglish
    13·
    17 hours ago

    breaks 300 year old law

    Narrator: it didn’t

  • neidu3@sh.itjust.worksEnglish
    432·
    1 day ago

    Is it really friction, though? It seems more like a case of one layer inducing mechanical work in the other, which in turn results in loss of efficiency due to inertia and actual friction within that layer.

    In other word, I read this akin to an inductive coil moving through a magnetic field and drives a motor with a load. This will cause the coil to resist the movement, but it can hardly be called friction.

    • Cocodapuf@lemmy.worldEnglish
      17·
      23 hours ago

      It seems more like a case of one layer inducing mechanical work in the other, which in turn results in loss of efficiency due to inertia and actual friction within that layer.

      Now, define friction.

      I know that sounds like just a pithy response without much thought put to it. But actually, that may be what friction is. I’ll also note that nothing about physics and the interactions of matter is actually as intuitive as it appears. For example one might say, “well friction is when two materials touch and rub against each other” but remember, materials never actually touch, the molecules of each material are only ever near each other at best. So what is happening that causes that resistive force?

      • partofthevoice@lemmy.zipEnglish
        1·
        20 hours ago

        The atoms repelling each other via the strong nuclear force… is that what causes resistive force? I don’t know, just asking,

        • Paranoid Factoid@lemmy.worldEnglish
          2·
          16 hours ago

          Atoms repel by electrostatic forces. Essentially, electro-magnetism. The strong nuclear force acts on subatomic particles at distances far shorter.

        • Cocodapuf@lemmy.worldEnglish
          1·
          18 hours ago

          Yeah, I think that pushes them apart, keeps them from actually occupying the same space. So that’s definitely involved. But why do molecules moving past each other lose momentum? I could make a guess, but I’m not actually certain. Like I said, physics tends to be pretty unintuitive at this scale.

          (Technically I suppose they’re not losing momentum, they’re exchanging it for heat)

          • partofthevoice@lemmy.zipEnglish
            2·
            18 hours ago

            I have a private theory that it’s just fields all the way down. E.g., no electrons (as in separate things), just observable points in the one electromagnetic field. This helps me intuit the idea that energy transfers between things — with “transfer” simply being a kind of interaction between separate fields.

            Electrons moving past each other slowing down? Can that be reproduced with an electron gun, or would this be based off a larger mass that includes other subatomic particles as well?

      • neidu3@sh.itjust.worksEnglish
        152·
        1 day ago

        My uneducated understanding/intuition: Mechanical resistance to movement between two surfaces that touch. This resistance is partially caused by imperfections in the two surfaces that cause the surfaces to slightly mesh (which is why the force pushing the surfaces together is proportional to the friction). Also, partially, I am sure there’s some electromagnetic laws at play on the molecular level that resists the movement.

        • kata1yst@sh.itjust.worksEnglish
          32·
          1 day ago

          You brushed against the real truth there. Haha. Stupid joke, sorry.

          The truth is that surfaces never “touch”. How do you touch an atom? Even an atom in a tight lattice or molecule is held in place only loosely by electromagnetic forces. The electron shells are a convenient idea more than they’re real, they’re not a real boundary for another atom to bump against. And the nucleus is so much tinier than the innermost shell it’s hard to wrap your mind around.

          Basically, surfaces don’t truly exist. In reality the surface is just a fuzzy area where things are limited in how close they can get before the forces between the electromagnetic layers push back.

          So friction is just when one electromagnetic fuzzy thing interferes with another electromagnetic fuzzy thing’s lateral motion, and that interference atom to atom creates movement in the lattice of each which creates heat.

          This finding is just that in special circumstances those electromagnetic fuzzy things can be a lot further apart when they interfere with each other.