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Define time, mass , or matter

  1. Oct 2, 2008 #1
    I was pondering the defining of time, mass, or matter ... wondered if any one could help ....
    However! First ponder this.

    obviously speed = distance divided by time ... and ... mass = weight x gravity
    The first question i ask. Can one of these variables(in their respective equations) exist with out the other? for ex. If there was no movement then there could be no time. Obviously there is no distance .. since there is no movement. Then in the begining was there no time .. before the "proposed" big bang theory.
    My friend argue there was still time but not in the sense we could comprehend. ? any theories .....

    propose you were in the middle of space ... where there were zero gravity .. then you would have no weight ... but wouldnt'y you still have mass .. or would you be massless ??? obviously you are still there.. so maybe theres is no such thing as zero gravity .. . So my question is .. is there always gravity on a body .. maybe like a " limit" process so minute to you seem weightless but really you are not. therefore you would always have mass ...So then What is matter .. ? i only ask that if one could prove zero gravity can be obtained.
     
    Last edited: Oct 2, 2008
  2. jcsd
  3. Oct 2, 2008 #2
    i would think that mass and force would be defined in terms of each other.

    the question of what diemensions are fundamental and why they are fundamental is very interesting.

    when a new fundamental dimension is defined in terms of other fundamental dimensions there is always a constant relating them. like the gravitational constant. if that constant is in reality everywhere equal to one then does that new fundamental dimension even need to exist? i would think obviously not. what if everything actually moves at the speed of light? would velocity be seen as a constant relating distance to time? so maybe time is unnecessary. hope that made sense.
     
  4. Oct 3, 2008 #3

    Nabeshin

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    Mass exists independent of gravity. A better definition than weight times gravity, in the classical sense, would come from newton's second law. Mass is the amount of inertia an object possesses, that is, its resistance to acceleration.

    Of course, acceleration is derived from measurements of distance and time. So mass is intricately tied to those two as well (or those two are intricately tied to mass).

    When considering whether or not there is movement in a universe and the implications that has for distance/time measurements, I think you have to consider a reference frame. If there is SOMETHING in the universe, surely there will still be distance. However, if there is nothing there is nothing to measure with respect to and the notion is meaningless. Time and space (distance) are intrinsic properties of our universe. They are simply the 4-D coordinate system we live in (x,y,z,t), so at least in our universe they will always be there.

    This is all classical, and I haven't considered at all any quantum or really even relativistic effects. But I think this still has a lot of ground underneath it.
     
  5. Oct 3, 2008 #4

    atyy

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    Different, not better.

    F=m1a [m1: 2nd law mass or "inertial mass"]
    F=GM1M2/r2 [M1,M2: gravitational mass].

    It is experimentally true that m1=M1.

    A particle that is (infinitely) far from any other masses has both inertial mass and gravitational mass - these are properties of the particle.

    When it comes into the gravitational field of another particle, it will feel a gravitational force, which we call weight.
     
  6. Oct 3, 2008 #5
    I'd argue that "beginning" is a point in time. Without "Time" how do you begin?
    So i'd say time began with Big Bang. Time is a dimension...Hence "space-time"
    And then i'd also ask how can you have a "before" Big Bang...If you claim there wasn't time.


    As far as the weight and matter. Weight = Matter x Gravity.
    Meaning Matter and Gravity are two separate things. Matter is the intrinsic property of an object. Matter is directly proportional to inertia, and inertia is our resistance to a force. Gravity is a force caused by curvature of space-time. Which is what matter causes....
    F = G[(m1/r^2)(m2/r^2)] Gravity is due to mass.. not mass itself.
     
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