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B LeSage gravitational theory: Can it be made to work?

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  1. Jun 3, 2017 #1
    I'm sure you are familiar with Le Sages physics and how it predicts gravitational drag. But what if no velocity vector matters except the direct line between the two gravitational objects? Does this fix Le Sages theory?
     
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  3. Jun 3, 2017 #2

    jedishrfu

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  4. Jun 3, 2017 #3

    sophiecentaur

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    What an excellent way to introduce a really obscure bit of Physics. I now feel a total dumbo. :biggrin:
    I'm sure there will be some PF member who has heard of it. I will watch with interest and probably feel an even bigger dumbo. (Perhaps an introductory link or two would have helped?)
     
  5. Jun 3, 2017 #4

    Vanadium 50

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    Really? A couple times a year someone re-discovers it and posts it here. Then they ignore the criticism, and finally the thread gets locked.

    Wikipedia has a couple pages of criticism: https://en.wikipedia.org/wiki/Le_Sage's_theory_of_gravitation In any event, this proposed fix a) is very complicated in that it replaces local fields with an action-at-a-distance that somehow knows what particle in the universe will be reacting to the source in the future. And b) this only patches one problem - the other ones, like the absence of a Pound-Rebka effect are still there.
     
  6. Jun 3, 2017 #5

    jedishrfu

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    Yeah, I usually monitor math posts and unanswered posts and that's how I stumbled across this. I've seen alternatives to gravity but never saw the names Fatio and LeSage before and had to look them up.

    As a physics major of the seventies I now feel I was short changed. We seldom discussed anything in a historical context until we got to quantum theory and then it got personal. It was a liberal arts school in the top 50 schools that graduated the dude who engineered the Brooklyn Bridge (its for sale and I can get it for you cheap, really.) The physics dept was very small but pretty top notch but we used lab equipment invented in the time of Faraday to give us some culture.
     
  7. Jun 3, 2017 #6
    But action at a distance applies to any gravitational theory. For example gravitons traveling infinite paths to find the particle.

    I think all the other problems can be similarly ignored or renormalized just as the equivalent problems in quantum theory are dealt with.
     
  8. Jun 3, 2017 #7

    mfb

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    Not to general relativity, and not to any quantum field theory either.
    I'm not sure what you mean here, but there is no action at a distance - the theories are local.
     
  9. Jun 3, 2017 #8

    sophiecentaur

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    There is only so much to be gained from examining old theories of Physics. They have faded out of existence probably for good reasons. Interesting but are they worth while losing too much sleep over? How worth while is it to re-discover ancient flaws? Frankly, I find the new stuff demanding enough.
    There isn't a Science History Forum, afaik. Perhaps it would be a useful addition to PF.
     
  10. Jun 3, 2017 #9

    Vanadium 50

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    As mfb says, GR is local, not action-at-a-distance. As taught in schools today, Newton isn't action at a distance either: gravity is due to a local field. I know of no alternatives to GR where gravity is not determined by a local field. The nature of this field can change in different theories, but it's always a local field. The whole point of LeSage is to provide an explanation for this local field in terms of unseen particles. This throws the baby out with the bathwater.

    There is no theory of gravity that I am aware of that proposes this.

    That logic is vacuous, in that it can be applied to any objection in any theory. "Don't worry about it. Maybe someone can fix it" is just about the weakest counter-argument I can imagine.
     
  11. Jun 3, 2017 #10
    Well thats because there is no theory of quantum gravity. So I don't see LeSage as being worse than nothing.
     
  12. Jun 3, 2017 #11

    mfb

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    "Nothing" is not the scale. General relativity is the scale. And LeSage gravity is not even visible on that scale.
     
  13. Jun 3, 2017 #12

    Vanadium 50

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    Mustang, you've moved from asking about a 300 year old theory to defending a 300 year old theory. Defending a 300 year old theory which makes many incorrect predictions is something many crackpots do. You are likely to get lumped in with them if you continue defending it.

    GR makes predictions different than LeSage (for example, that the earth doesn't blow up in a nanosecond). The data matches GR and not LeSage. Maintaining that LeSage is correct (and by necessity, GR is wrong) in the face of this is not doing science.
     
  14. Jun 3, 2017 #13

    Nugatory

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    You are right that it is not worse than nothing, but that's the wrong question. The right question is whether it's worse than general relativity, and by most reasonable definitions of "worse", it is.
     
  15. Jun 3, 2017 #14
    Actually the data does not match either theory, which is why dark matter and other fudge factors were introduced.
     
  16. Jun 3, 2017 #15

    Drakkith

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    Before you discard a theory you need to make sure its predictions don't match observations. We don't yet know if dark matter exists or if GR is wrong, so it's far too early to make any such claims. If dark matter does indeed exist then GR is still a perfectly valid theory (unless invalidated by other means).
     
  17. Jun 4, 2017 #16

    jedishrfu

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    This thread has devolved into arguing whether LeSage's theory is better than GR which is clearly not a mainstream science view. Consequently we have decided to close this thread and thank everyone for their contributions.

    Take care,
    Jedishrfu
     
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