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The ant and the Melon

  1. Jul 24, 2013 #1
    so i was arguing with a friend of mine , and one moment it just clicked to me that *bare with me my scientific inaccuracies *

    what if the universe is just one huge sheet of cloth , with 4 people holding it at each vertex
    now imagine a big melon in the middle , of course we all know it would go down and make a curve around it * like what einstein and others said *
    now imagine an ant standing right next to the melon ( on the sheet of cloth ) , and ant on the melon itself
    now what if the two ants move with the same speed , the one on the melon would cover more distances in less time , while the one on the sheet covers less distances in the same time * i am talking about horizontal distance since the ant cant really see the curve , ants are stupid they dont understand curves ! * , wouldn't the ant think that time has slowed down for the other ant ? because it takes it more time to cover the same distance that the ant on the melon covers ?
    i am just trying to understand how time-space thing work by imagining it ..
    now this is probably the most cartoonistic way to explain how gravity would affect * if it is even half correct * , i just want to know how correct could that thought be ?
  2. jcsd
  3. Jul 24, 2013 #2


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  4. Jul 24, 2013 #3


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    Staff: Mentor

    You're definitely on the right track when you think about the ant who doesn't know about curvature moving around in a curved spacetime.

    However, modeling gravitational curvature as a sheet with a weight in the middle of it is a fairly awful analogy, does more harm than good when you go to study the interesting properties of the spacetime that we live in.

    But if it's such a terrible analogy, then why, you might ask, does it keep on getting printed in books and magazine articles and the like? Well, it's really hard to to print a picture of a four-dimensional curved spacetime on a two-dimensional flat piece of paper :smile:

    A.T has done some pretty good animations, posted them to this forum, you'll find them if you search some older posts (or you can just look right above this post, because he's way ahead of me).
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