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About Fourth Dimension

  1. Jun 18, 2015 #1
    Hey guys,

    I'm a newbie here. Is it true that one could understand fifth and above dimensions only if we get hold of fourth dimension and I've seen videos and read about fourth dimension but couldn't get it completely and exactly. So, I want your help here. Be mellow as much as you can.

    Thank you.
  2. jcsd
  3. Jun 18, 2015 #2
    I want to help you but I didnt understand your question.
  4. Jun 18, 2015 #3


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    The "fourth" dimension in physics is time, so I'm assuming you mean a 4th dimension of space, which as far as we know does not actually exist. String theory postulates up to 11 dimensions, but there are no tests to see if these actually exist so string theory remains a form of math with no known correspondence to reality.

    In math, "dimension" is just a degree of freedom and you can have as many as you like and there's nothing difficult about understanding them, they are just numbers.
  5. Jun 18, 2015 #4
    We only experience 3 space dimensions, and we don't have any kind of apparatus which hints at additional dimensions beyond what we can experience directly.
    As Phinds, says it is possible to construct mathematical models with any number of dimensions, but if they don't correspond to any observable reality these models are not of much practical value.
    String theories may possibly be verified in the future, and if they are we will have taken our understanding of nature into a whole new realm involving simultaneously something like 6 additional dimensions all at a sub microscopic scale, but for now though string theories are not verifiable, and are simply 'what if..?' based on nothing but math.
    There is no definitive 'fourth' or higher dimension of space in any of today's mainstream physics.
    What kind of sources have you been looking at which suggests there is?
  6. Jun 18, 2015 #5


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    One of the basic rules of science, like engineering, is add no unnecessary parts. You only need 3 spatial dimensions and an origin to uniquely define a location in space. Time is added as a fourth 'dimension' in GR as a mathematical convenience for bodies in motion. So there is no physical motivation for extra spatial dimensions. Extra dimensions do pop out of the math in things like string theory, but, this does not confer them any objective reality.
    Last edited: Jun 18, 2015
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