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Is anything on Earth- 4 dimensional? 2 dimensional? 1 dimensional?

  1. YES

    4 vote(s)
    44.4%
  2. NO

    5 vote(s)
    55.6%
  1. Jan 6, 2010 #1
    Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    As you can see now, I'm really confused. And I apologize for the question.

    I was always taught that I am living exclusively within a three dimensional Earth.
    Is there anything in or on Earth that is one dimensional? I think that I was taught that one dimension was simply directional lines that could only be preceived as a thought.

    I think that we learned that two dimensions were designs, figures, flat drawings but had zero depth and could only be preceived as a thought.

    The way I learned it was that the fourth dimension was basically a combination of two or more of the three dimensions; and that they were not tied to any location and that they could freely move through each other.

    I'm sure that all this is hopelessly simplified, but the only answer that I am trying to get is whether there are only three dimensions on Earth.
     
  2. jcsd
  3. Jan 6, 2010 #2
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Our entire universe is subject to a 3+1-dimensional space-time, 3 spatial dimensions and 1 temporal dimension. Everything in our universe is therefore embedded in a 4-dimentional manifold we call space-time.

    If we keep to the three spatial dimentions and ask if there are 2- or 1-dimensional objects in our universe, ask yourself, what would be their properties? What would they be made of? Mass and charge densities would have to be infinite or momoent of inertia would have to be zero. Atoms, of which matter is formed, exist in 3 dimentions.

    So there cannot be anything non-3-dimensional objects in the universe.
     
  4. Jan 6, 2010 #3

    Andy Resnick

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    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Interfaces between immiscible fluids are essentially 2-dimensional. Electrons are 0-dimensional to the limits of experimental error.
     
  5. Jan 6, 2010 #4

    HallsofIvy

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    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    What do you mean by "dimension"? For me, and I think most people, a dimension is just a way of assigning a numerical label to something. Physics deals with "events"- thing that happen at a specific place at a specific time. In order to designate a specific our experience is that three numbers are required. An additional number is required to specify the time of the event. I think it would be better to ask, "Is there any event in our world that is not four dimensional".

    Of course, string theory computations require more dimensions- supposedly those are "rolled up" so small we don't notice them. But that is far from the standard theory at present.
     
  6. Jan 6, 2010 #5
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    You could argue that there are five dimensions, 4 spatial and one for time. The fourth spatial dimension modifies the normal x,y,z dimensions. In calculating the position of an object relative to another you need to take this 4th dimension into account - a bit difficult because it varies according to the varying strength (and direction) of the gravitational field that exists between the objects.
     
  7. Jan 6, 2010 #6
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    You might consider the image on a movie screen two dimensional.
     
  8. Jan 6, 2010 #7
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?


    Thank you so very much.
    For the first time ever, by explaining it this way, it seems to make sense to me.
    ronandkryn
     
  9. Jan 7, 2010 #8
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Graphene is a purely two-dimentional substnance.
     
  10. Jan 8, 2010 #9

    Char. Limit

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    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Not entirely: after taking the the atoms into account, graphene has a width of 2 times the covalent bonding radius of Carbon. My exact number might be off, but graphene is 3-d.

    Also, aren't all shadows n-1 dimensions relative to an n-dimensional object? So a 3-d object, which we can all agree exists, casts a shadow, correct? Thus, this shadow exists. Also, since the object was 3-d, the shadow is 2-d, thus, a 2-d object exists.

    Why I just did all of that instead of just saying shadows, I do not know.
     
  11. Jan 8, 2010 #10
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    But aren't shadows cast on a surface which at the molecular level will have irregularities making it a 3-d structure?
     
  12. Jan 8, 2010 #11
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    I don't like wikipedia as much as the next science fan, but from the source:

    "Graphene is a flat monolayer of carbon atoms tightly packed into a two-dimensional (2D) honeycomb lattice, and is a basic building block for graphitic materials of all other dimensionalities. It can be wrapped up into 0D fullerenes, rolled into 1D nanotubes or stacked into 3D graphite.[1]"
     
  13. Jan 8, 2010 #12
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Some would suggest, with a great deal of support, that our known Universe is a 3-D world on the 'surface' of a 4-D space of some sort. Much like the 2-D surface on the 3-D spherical orange...
    That means that if you were to send out a laser beam directly in front of you that many, many years later it would return to you--from behind!
     
  14. Jan 8, 2010 #13
    Re: Is anything on Earth--- 4 dimensional? 2 dimensional? 1 dimensional?

    Wikipedia also says "Graphene is a one-atom-thick planar sheet ...."
     
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