• SparroHawc@lemmy.zip
    link
    fedilink
    English
    arrow-up
    0
    ·
    10 days ago

    …The Planck constant is a set distance. It’s being used here to define other things as a constant. The very article on the kilogram states outright that SI units’ foundation is three constants: “a specific transition frequency of the caesium-133 atom, the speed of light, and the Planck constant.”

    Vacuum permeability is how much electric currents affect magnetic fields in a vacuum. As in, when there are no other interferences. It is not variable. The speed of light when there is no interference is not ‘affected by’ vacuum permability any more than a cartesian graph is ‘affected by’ the set of real numbers. Vacuum permeability describes vacuum, it doesn’t define it. Same goes for permittivity.

    You ARE correct about the kilogram no longer being a number of specific atoms, though.

    • Natanael@slrpnk.net
      link
      fedilink
      English
      arrow-up
      2
      ·
      3 days ago

      My entire point is that while there are absolute properties of spacetime, all we know are rough measurements and all our derived laws are calculated as ratios and relations between different properties, which is precisely why it’s possible to insert scaling factors in our math and change every number with no visible effect in behavior despite drastic changes under the hood.

      Like how a few physicists describe expansion of the universe as objects in the universe shrinking, and the math ends up essentially identical. Because both formulas describe the exact same ratios and proportions so the behavior is the same but the mechanics causing it is different and we can’t not tell the difference.