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Shape of the universe

  1. Apr 7, 2005 #1
    I'm not overly familiar with GR, but I have heard that gravity is basically a result of the curvature of space. Its not an attractive force so much as its a consequence of travelling on a curved surface. But I've also read that observing cosmic microwave background hot spots leads to a flat universe. So can the universe be flat, if GR claims gravity needs curves?
  2. jcsd
  3. Apr 8, 2005 #2


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    Tomato, tomawto.

    I think this was covered by someone else in another thread recently, but the basic idea is that massive objects are like little "dimples" in spacetime, despite its overall flatness. Imagine a large, flat rubber sheet with a few marbles resting on the surface. The marbles make an impression locally, but the overall sheet is flat. In the real world, the small-scale curvature due to gravitationally bound objects can be demonstrated with phenomena like gravitational lensing.
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