Can we consider this as a dimension?

Discussion in 'Physics & Math' started by Tedman"Xp", Apr 14, 2002.

  1. Tedman"Xp" Registered Senior Member

    Messages:
    41
    I really dont undersstand why im saying this . Whether it is irrelevant or relevant youll give your opinion.it just came up to my mind that there is another visible dimension in our world...The possibility that any body could reach any point with one of its extremities on its plane without changing its own position.As you can realize I dont even know how to call this fact so I will possibly need your help.

    Please Register or Log in to view the hidden image!

     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Hoth Registered Senior Member

    Messages:
    383
    Well, time is a dimension where we only see slices and not the whole. It seems to fit the description... but it's already one of our 4 known dimensions even though we don't percieve it in as complete of a way as the other 3.

    A visible dimension, you say? If such a dimension were visible, we'd already know about it. You'll have to explain more if it's going to make sense...
     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Tedman"Xp" Registered Senior Member

    Messages:
    41
    About being visible forget about it ... It doesnt really make any sense.The dimension should be heading to the fact the every body has its own plane . Can we consider it as an everexpanding 2d grid?
     
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. proycon Registered Member

    Messages:
    16
    Congratulations

    Please Register or Log in to view the hidden image!

    You've just discovered a dimension called size/span if I interpreted you correctly

    Please Register or Log in to view the hidden image!

    )

    Intersting thought...but I would not consider this as an extra dimension since it's already covered in our 3d space...

    That 'body' that you mentioned is actually a large body consisting out of smaller units which just move through spacetime and can reachout, so there are still only 3 space coordinates involved and one time coordinate... So I don't think this qualifies as an extra dimension since it doesn't really add something new....
     
  8. Tedman"Xp" Registered Senior Member

    Messages:
    41
    Yes !!! Thank you but wht do you mean by something new?
     
  9. proycon Registered Member

    Messages:
    16
    I mean that it's not a new dimension since it's just an aspect of 3D space... 'reaching out' does not require any extra dimension, it's just the movement of subbodies through 3D space... I wouldn't consider it a dimension...
     
  10. esp Registered Senior Member

    Messages:
    908
    w,x,y,z&t

    I agree.

    The infinite 2d grid refered to would constitute multiple intersections in x and y. I don't think that it could be classed as 'w'.
     
  11. Tedman"Xp" Registered Senior Member

    Messages:
    41
    Well guys yes. Probably this is not a new dimension but I was thinking how position works when the space-time is warped . Does this plane change when a body is through this conditions?Can we think that this body would appear to be tied from our perspective as the observers?
     
  12. Tedman"Xp" Registered Senior Member

    Messages:
    41
    Can anyone answer my questions?
     
  13. proycon Registered Member

    Messages:
    16
    What do you mean exactly?

    How the position changes in a warped space?

    Well, that's easy... Gravity is considered a warping of space (Einstein) and you clearly see that it affects the position of objects...
     
  14. Tedman"Xp" Registered Senior Member

    Messages:
    41
    have you ever been there to tell people about what happens
     
  15. Crisp Gone 4ever Registered Senior Member

    Messages:
    1,339
    Hi Tedman,

    Position in a curved spacetime is described just as you would describe the position on a circle or a sphere (curved surfaces): you use coordinates that have a special relation between them.

    For example: to locate a point on a sphere, you need to know two coordinates: two angles are sufficient (in a 3D world) or, if you are living on the sphere, you can use x and y coordinates (only two, the surface of a sphere is two-dimensional). When you use x and y, you need to take the curvature into account. The distance d between two points (x1,y1) and (x2,y2) on a sphere is not the Euclidian:

    d<sup>2</sup> = (x2 - x1)<sup>2</sup> + (y2 - y1)<sup>2</sup>

    since that is the length of a straight line between the two points. What we want to know is the distance between the points on the sphere. I am a bit too lazy to do the math myself, but I am sure you will agree that you need to take a different formula to calculate the length of a line that connects two points on the sphere.

    For curved spacetime things work in exactly the same way: we use the coordinates (x,y,z,t) to locate an object in spacetime, but since spacetime is curved, we need to use a special relationship between the coordinates to calculate a length. This special relationship, that defines the distance between two points, is called a metric. I could be wrong on this one (never really got into the maths myself) but I believe the metric used for curved spacetime is called the Riemann-metric.

    Hope this more or less answers your question,

    Crisp
     

Share This Page