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GR is no more or less wrong than Newtonian physics.

flatline 7y ago
IANAP but I’m reasonably confident in asserting that GR is less wrong than Newtonian gravity, based on each models’ predictive power.
pdonis 7y ago
> GR is no more or less wrong than Newtonian physics. Then why does GR make more accurate predictions?
- hudon 7y ago
  At low speeds relative to the speed of light, they have the same accuracy don't they? And in that case, the Newton model is simpler so more useful. At high speeds, it becomes inaccurate and then you need the other model. So there is no global "right" or "wrong", just different measures of usefulness depending the problem constraints.
  - Supermancho 7y ago
    > At low speeds relative to the speed of light, they have the same accuracy don't they? When measuring signal (ie radio, light, gravity) from slow speed perspectives, newtonian physics is not as accurate - https://futurism.com/newtonian-physics-vs-special-realtivity https://futurism.com/newtonian-physics-vs-special-realtivity - Eg we actually need to account for it between gps sattelites and we do so from the perspective of GR as well as the recent evidence of gravity propogation being restricted to localization (ie roughly the speed of light)
    - hudon 7y ago
      Yup. And when you need to measure where artillery shells land, the GR model is overkill and you'll waste less time by using a Newtonian prediction. I think this proves my point?
      - kyralis 7y ago
        "Newtonion physics is a perfectly acceptable approximation in many circumstances" and "GR is less wrong than Newtonion physics" are not in conflict. Newtonion physics can absolutely be "more wrong" and "useful in many circumstances" at the same time- and in fact is!
      - cma 7y ago
        So GR is more right in more scenarios and that makes it no more or less wrong?
        withants 7y ago
        i am a big fan of newtonian mechanics
      - bashinator 7y ago
        If your point is that they're both equally wrong, then no, I think you've disproven your own point. There are no circumstances in which Newtonian math produces better results than GR. That the latter is more complex is not relevant to the discussion of whether one is more accurate for a wider range of phenomena than the other.
      - pdonis 7y ago
        > I think this proves my point? No, because "less accurate but in practical terms the difference can often be ignored" is not the same as "the same accuracy".
  - Koshkin 7y ago
    > there is no global "right" or "wrong" You are wrong, so there is.
  - pdonis 7y ago
    > At low speeds relative to the speed of light, they have the same accuracy don't they? GR is always more accurate, but the increased accuracy is not always needed; at low speeds relative to the speed of light the difference is often too small to matter in practical terms.
  - krastanov 7y ago
    Besides the valid points of the other commenters, I have a nitpick: It is special relativity that deals with things near the speed of light, you do not need GR for it. GR is necessary to account for strong gravitational fields.

IANAP but I’m reasonably confident in asserting that GR is less wrong than Newtonian gravity, based on each models’ predictive power.

pdonis 7y ago

> GR is no more or less wrong than Newtonian physics. Then why does GR make more accurate predictions?

hudon 7y ago
At low speeds relative to the speed of light, they have the same accuracy don't they? And in that case, the Newton model is simpler so more useful. At high speeds, it becomes inaccurate and then you need the other model. So there is no global "right" or "wrong", just different measures of usefulness depending the problem constraints.
- Supermancho 7y ago
  > At low speeds relative to the speed of light, they have the same accuracy don't they? When measuring signal (ie radio, light, gravity) from slow speed perspectives, newtonian physics is not as accurate - https://futurism.com/newtonian-physics-vs-special-realtivity https://futurism.com/newtonian-physics-vs-special-realtivity - Eg we actually need to account for it between gps sattelites and we do so from the perspective of GR as well as the recent evidence of gravity propogation being restricted to localization (ie roughly the speed of light)
  - hudon 7y ago
    Yup. And when you need to measure where artillery shells land, the GR model is overkill and you'll waste less time by using a Newtonian prediction. I think this proves my point?
    - kyralis 7y ago
      "Newtonion physics is a perfectly acceptable approximation in many circumstances" and "GR is less wrong than Newtonion physics" are not in conflict. Newtonion physics can absolutely be "more wrong" and "useful in many circumstances" at the same time- and in fact is!
    - cma 7y ago
      So GR is more right in more scenarios and that makes it no more or less wrong?
      - withants 7y ago
        i am a big fan of newtonian mechanics
    - bashinator 7y ago
      If your point is that they're both equally wrong, then no, I think you've disproven your own point. There are no circumstances in which Newtonian math produces better results than GR. That the latter is more complex is not relevant to the discussion of whether one is more accurate for a wider range of phenomena than the other.
    - pdonis 7y ago
      > I think this proves my point? No, because "less accurate but in practical terms the difference can often be ignored" is not the same as "the same accuracy".
- Koshkin 7y ago
  > there is no global "right" or "wrong" You are wrong, so there is.
- pdonis 7y ago
  > At low speeds relative to the speed of light, they have the same accuracy don't they? GR is always more accurate, but the increased accuracy is not always needed; at low speeds relative to the speed of light the difference is often too small to matter in practical terms.
- krastanov 7y ago
  Besides the valid points of the other commenters, I have a nitpick: It is special relativity that deals with things near the speed of light, you do not need GR for it. GR is necessary to account for strong gravitational fields.