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Newton's bucket and Galilean relativity

  1. Oct 11, 2004 #1
    I'm re-reading Greene's The Fabric of the Cosmos. He describes Newton as explaining his (Newton's, not Greene's!) thought experiment of the bucket by the existence of absolute space: something with respect to which rotating objects rotate, even in seemingly empty space.

    Did Newton ever discuss why rotational motion was absolute, but constant velocity motion was relative? Or did he in fact think all motion was absolute? I guess that would mean he would have predicted that the Michelson-Morley would have found an ether wind.
     
  2. jcsd
  3. Oct 11, 2004 #2
    He thought that time and space, and therefore all motion, was absolute.
     
  4. Oct 11, 2004 #3
    so he thought that when you were on a steadily moving ship and you dropped a coin from your hand, the reason it hit you on the foot was that both you and the ship were moving relative to absolute space?

    Did Newton think there were mechanical experiments that could determine absolute motion?
     
  5. Oct 11, 2004 #4
    I'm not sure I understand your question. If you and the coin are on a steadily moving ship, the coin will drop straight down to the floor below where you held it when you dropped it.
     
  6. Oct 11, 2004 #5
    Geometer are you being funny?

    Newton took into account velocities but the Lorenz transformation is the theorem that brings the observer into account and each level to predict an absolute K has not been established or verified.

    As each article of matter has a relative affect on each other since the constant speed of light reveals a result; the realization of time, our fourth demension, has to be taken into account and to acknowledge the interwoven effect of everything to itself has beautified many explanations.

    Has it been thought yet that a negative thereof could simplify dark matter?
     
  7. Jun 22, 2005 #6

    GAK

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    anyone help me?

    i can't understand why Newton had to propose anything to explain the bucket? It seems that he could understand the individule water bits (whatever he wanted to call them) each wanted to proceed in a straight line and upon coliding with the bucket would pile up atop one another.

    Why wouldn't he have concluded that? Surely i'm too uneducated to understand.

    thanx
    jerry
     
  8. May 2, 2011 #7
    Greene wasn't dropping the bucket he had it suspended from a rope which you wound up.

    The bucket slowly starts spinning to unwind and now look at the reference frames .. look up "bucket argument" in wikipedia.

    The problem is the water does not stay level it produces a concave shape.

    It leads into the problem of fictional forces (centrifugal force, Coriolis force, and Euler force) what are they pushing on if anything. Once you accept there can be fictional forces it leads directly into General relativity that is gravity is a fictional force quote below from GR in wiki.

    I think that is the only weak part of the book it never really explains why the bucket is important (in that it defies Newtonian analysis) and he never really brings in fictional forces.
     
    Last edited: May 2, 2011
  9. May 3, 2011 #8
    This is an ancient thread :rolleyes:
    Still it may be useful to give the explanation "straight from the horse's mouth", here:

    http://gravitee.tripod.com/definitions.htm

    Just press "cancel" and search for "water"; you'll find the discussion near the end of the Scholium.

    Harald
     
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