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The morley-michealson experiment i need help with the reasoning or lack of

  1. May 5, 2012 #1
    When this experiment was used to support SR( having no need for a medium of propagation and interaction) and the concept of an aether was dismissed, there was an overall assumption made by those prominent at the time that the aether must be rigid and at rest.
    Now that we know through the implications of General Relativity that even our OWN medium (space-time) has curvature, is capable of expansion and contraction,interacts with light gravitionally, is it not been made slightly redundant to up hold this requirement of rigivity and stationary state for any medium hypothetical or physical?
    I'm not trying to be rude i just need the point i dropped the ball in terms of having to expect these conditions of existence of something.
  2. jcsd
  3. May 5, 2012 #2


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    i can't quite grok the connection of the MMX and Minkowski space-time.

    the assumption of the MMX was that this aether did exist and, at least during some season of the year, the Earth should be moving though it at around 50,000 km/hr which would be enough to see a fringe shift.

    so the result of the experiment is negative, no fringe shift, during any time of year. if something thought to exist simply show no manifestation of existence after multiple attempts to tease out such a manifestation, what normally happens in science is that they begin to become dubious about the notion of that thing that exists but shows no sign of its existence.

    that's the only reasoning i know of in the interpretation of the null result of the MMX.
  4. May 5, 2012 #3
    Well in the definition of Newton of the concept he described it as a ''dimensionless medium" so how they came to the assumption of it being rigid and stationary has me confused. I can see how newtonian physics demands a rigid stationary body, but then again, all observations require such.
  5. May 5, 2012 #4
    I wasn't laying claim to pursuing the concept of an aether but i was simply stating i think its dismissal as a means of support to Special Relativity was made a little redundant in light of what vague descriptions we had of this "eather" beforehand .
  6. May 5, 2012 #5


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    Staff: Mentor

    When people say "the MM experiment proves there is no ether", they're skipping a few steps in the interests of simplicity. If we were to be exactly rigorously precise, we'd say "the MM experiment shows that the measured speed of light does not vary with the earth's motion".

    There are (at least) two possible explanations for this:
    1) There is no ether.
    2) There is an ether, and it has some strange and interesting and complicated properties that make it undetectable by all the MM experiments done so far.

    If I understand your question properly, you're asking why we accept #1 instead of #2. It's because #1 leads to a clean, logically consistent, and elegant theory that has been confirmed a million times over by other experiments. Sure, it could turn out that there's a #2 theory that better explains the world... But until someone comes up with experimental observations that are not be explained by current theory, that's just idle speculation.
    Last edited: May 5, 2012
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