• barsoap@lemm.ee
    link
    fedilink
    arrow-up
    14
    ·
    11 months ago

    The heliocentric models predicted the orbits worse than epicyclic geocentric ones and that is the reason Galileo was told to shut up, the court transcript is like 99% science and then a single subordinate clause saying “it also contradicts the bible”.

    Galileo insisted on circular orbits which was his downfall, ironically “because circles are perfect and god would furnish the universe perfect”: That kind of religious language while also being worse science than what was already established did him in. Kepler, based on Brahe’s data, was the first one to get a heliocentric model right and more accurate than the epicyclic ones.

    Also earth doesn’t revolve around the sun. If anything both revolve around their shared centre of gravity but really it’s a matter of your frame of reference. Paraphrasing Archimedes: Give me a fixed point in the universe and I will move all your models.

    • spikespaz@programming.dev
      link
      fedilink
      arrow-up
      2
      arrow-down
      1
      ·
      11 months ago

      The sun. Does the earth and moon orbit a gravitational center that they share? Does that center revolve around the sun? How imperceptible is this, considering the shared point is likely inside the earth given the difference between its mass and lua’s?

      • dellish@lemmy.world
        link
        fedilink
        arrow-up
        7
        ·
        11 months ago

        The moon is a decent fraction if the Earth’s mass. It has been a while since I calculated it but I recall the “shared gravitation centre” is actually outside the Earth.

        • Natanael@slrpnk.net
          link
          fedilink
          arrow-up
          3
          ·
          11 months ago

          Doesn’t that also technically mean that the earth’s movement technically wobbles fully inside and fully outside it’s orbital line?

      • barsoap@lemm.ee
        link
        fedilink
        arrow-up
        4
        ·
        11 months ago

        Does the earth and moon orbit a gravitational center that they share?

        Yes.

        Does that center revolve around the sun?

        No, it revolves around its shared centre with the sun. Things get complicated fast in gravity with more than two objects involved.

        How imperceptible is this, considering the shared point is likely inside the earth given the difference between its mass and lua’s?

        It’s how we can detect exoplanets. Well, we can tell there must be these and these planets based on the star’s wobble dunno if we can do the same for moons of planets: It would certainly work in principle but our instruments might not be good enough.