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Is time a vector?

  1. Oct 3, 2003 #1
    it is the question which has baffled me since i took vector analysis.
    later somewhere i read that r.p.feynman too tried to dwell in it.i have post this thread in physics forum a year before and there were many replies. but not with that mathematical presicion .enpugh of background, now my question is-
    is time a vector , or more specifically a tensor?
    a bit of mathematical description might be fruitful-
    a vector is also a tensor, when i say time is a tensor i meant a tensor of rank more than or equal to rank one. a vector is tensor of rank one. and a scaler is of rank zero. as we need three set of independent scalers to define a vector in ordinary geometry(or four-in space time or minkowskien geometry), we need 3*3 or nine independent scalers to define a tensor of rank two completely(or we need 3 tensors of rank one(vector) to define a tensor of rank two).
    lets first discuss aspect of this question pertinent to physics.

    WE COULD SAY TIME IS A VECTOR AND ITS DIRECTION IS IN DIRECTION OF INCREASING ENTROPY, WHICH U USUALLY CALL THE FUTURE(BUT THAT TUTOLOGY IS RATHER INCORRECT, FUTURE IS DEFINED BY TIME ITSELF , WE CANNOT USE FUTER TO DEFINE TIME BACK, WHAT WE COULD USE IS ANOTHER PHYSICAL QUANTITY WHICH IS INDEPENDENT OF TIME)
    SECOND LAW OF THERMODYNAMICS INSURES US THAT WE HAVE THIS QUANTITY
    AN ALTERNATE DIRECTION MAY BE THAT OF IN WHICH TOTAL ENERGY REMAINS SAME, THIS DEFINITION WOULD PROVE INEXISTENCE OF NEGETIVE TIME VECTOR OR IN RATHER ORDINARY WORDS TIME FLOWING BACK.
    BUT ENEERGY DOESNT CHANGE SO WE WONT HAVE A +VE DIRECTION FOR TIME VECTOR.
    SO WE WILL USE A TERM RELATED WITH ENERGY WHCIH CHANGES,IT IS ENTROPY WHICH MEASURE CONVERTION OF USEFUL ENERGY INTO UNUSEFUL .OR WE MAY SAY IT MEASURES DEGRRE OF DISORDER(ITS A PRECISE STATISTICAL STATEMENT)
    SO WE HAVE DIRECTION OF TIME.
    NOW SOME MATHEMATICAL ASPECTS-
    WHEN WE SAY SOMETHING IS A VECTOR WE MEANT BY IT-
    1)IT FOLLOWS LAWS OF VECTOR ADDITION
    2) IT COULD BE FRACTIONED INTO INDEPENDENT COMPONENTS- WHICH OBEYS PRINCIPAL OF SUPERPOSITION
    THEORY OF GR ASSURES US THAT WE COULD HAVE COMPONENTS OF TIME, A DIRECTION OF TIME LITTLE INCLINED TO THAT OF FORWERD DIRECTION MEANS A BIT SLOW PROGRESS IN TIME, WHICH IS SUPPORTED BY SPECIAL RELATIVITY.
    ON THIS POINT I WOULD LIKE TO HAVE UR COMMENTS , I WORKED ON IT A BIT, AS A PASSTIME, AND I THINK TIME COULD BE PROVED AS A TENSOR OF RANK TWO.
    PEOPLE WHO ASSUMES THMESELVES AS PHYLOSPHERS OF PHYSICS NEED NOT COMMENT, THIS SUBJECT IS FOR THOSE WHO UNDERSTAND ITS MASTHEMATICAL INTRICACIES.
    PROBLEM WITH PHYLOSRS OF PHYSICS IS THAT THEY NEVER HAD ENOUGH MATHEMATICS TO HAVE TANGIBLE GRASP OVER PHYSICS.
    ON THIS POINT I INVITE UR COMMENTS WHICH MAY PROVIDE A PUSH IN +VE DIRECTION TO UNDERSTANDING OF THIS QUESTION
    GOODNIGHT/HAVE A NICE DAY
     
    Last edited: Oct 3, 2003
  2. jcsd
  3. Oct 3, 2003 #2

    HallsofIvy

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    I would interpret this in the basic sense in which one can interpret individual components of a vector as a vector "in that direction". For example, we can think of the vector <3, 2, 1> as the sum of 3 vectors <3, 0, 0>+ <0, 2, 0>+ <0, 0, 1> or 3i+ 2j+ k- the "x- component" represents a vector in the x direction.

    Certainly any "event" is a four vector- x, y, z, and t- and that implies vectors in each of those directions.
     
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