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Einstein on Space

  1. Sep 20, 2010 #1
    Found this quote years ago...can anyone help
    me understand it? I don't think it is out of
    context, just a bit vague to my pea brain.
    I think it can be found in more than one
    place; I might have gotten it from "Meaning
    of Relativity", but I loaned it and it's still out.

    Einstein on Space

    "When a smaller box s is situated, relatively at rest, inside the hollow space of a larger box S, then the hollow space of s is a part of the hollow space of S, and the same "space", which contains both of them, belongs to each of the boxes. When s is in motion with respect to S, however, the concept is less simple. One is then inclined to think that s encloses always the same space, but a variable part of the space S. It then becomes necessary to apportion to each box its particular space, not thought of as bounded, and to assume that these two spaces are in motion with respect to each other.

    Before one has become aware of this complication, space appears as an unbounded medium or container in which material objects swim around. But it must now be remembered that there is an infinite number of spaces, which are in motion with respect to each other. The concept of space as something existing objectively and independent of things belongs to pre-scientific thought, but not so the idea of the existence of an infinite number of spaces in motion relatively to each other. This latter idea is indeed logically unavoidable, but is far from having played a considerable role even in scientific thought."
  2. jcsd
  3. Sep 20, 2010 #2
    Different observers in relative motion have different spaces. What an observer sees as space is a particular slice of spacetime.

    You can see this clearly by taking an accelerating observer who moves with respect to different spaces.
  4. Sep 20, 2010 #3
    1) Is(can) the observer (be) in the small box? I don't see
    more than one observer in this thought experiment.

    2) Does it necessarily refer to GR...or is it only referring
    to SR? Since you mention "accelerating".
  5. Sep 20, 2010 #4
    This is strictly SR.

    What is it you do not understand about my answer?
  6. Sep 20, 2010 #5
    "but is far from having played a considerable role even in scientific thought."

    Looks to me that Albert was complaining as well. Do you think
    that his concerns are no longer valid...or do you suspect that
    "it" is true even for modern theories? And why do you mention
  7. Sep 20, 2010 #6
    Nowadays, special relativity with all its implications, is fully accepted. But that was not the case when Einstein wrote this almost 100 years ago. It took about two decades for special and general relativity to be come fully mainstream.

    Actually to help you understand the situation from a different perspective. However it appears this is simply confusing you.
  8. Sep 20, 2010 #7
    I put the observer in the small box...using the perspective of GR
    to understand a SR thought experiment does confuse me. But,
    I admitted confusion from the start; both philosophically and
    scientificly. Could you expand your thoughts a tiny bit? I am
    just beginning to catch on.
  9. Sep 20, 2010 #8
    Acceleration is not GR, acceleration can be perfectly well handled by SR.

    What an observer considers to be space (e.g. x, y, z) is not the same space as what another observer who moves relative to the first observer considers space. The unity is in spacetime, each observer sees space as a particular 'slice' of that spacetime. Think about taking a slice of bread cutting straight down or with an angle, she slice represents space.
  10. Sep 20, 2010 #9
    Yes...RELATIVITY...I think I was expecting too much from
    Albert's quote. Thanks for your time. If you have anything
    to add, please do.
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