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B "Length contraction" prior to observation/measurement

  1. Apr 12, 2016 #1
    Since special relativity insists that length is not invariant but rather depends on the frame of reference from which an object or distance is observed... and since the cosmos is many billions of years older than any possible observer, then objects and the distances between them must exist independently from all varieties of referential frames.
    Example: A frame of reference approaching Earth at .86c will, according to SR, measure its diameter to be about 4000 miles in the direction of the approach. But Earth hasn't changed much from its 8000 mile diameter in billions of years, so how it might appear from such a frame has nothing to do with its actual, physical diameter, which does "vary" with how it is measured.
    It all comes down to the fact that SR denies an objective world in favor of an infinite number of possible "subjective" perceptions of the world. Open for discussion.
  2. jcsd
  3. Apr 12, 2016 #2


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    Staff: Mentor

    Before you write off length contraction as something subjective, you should study and understand Bell's spaceship "paradox" - google will find many references.

    In any case, it simply untrue (and probably based on a misunderstanding) to say that relativity "denies an objective world". It describes the real and objective universe in which we live - it just so happens that that universe doesn't behave the way our common sense, which is biased by a lifetime surrounded by objects moving at speeds that are small compared with the speed of light, leads us to expect.

    As this thread is based on a faulty premise, it is closed
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