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Space time curved

  1. Oct 10, 2015 #1
    There exist evidence that space time fabric can be curved arround massive objects?
  2. jcsd
  3. Oct 10, 2015 #2
  4. Oct 10, 2015 #3
    i mean how?
    can any one explain?
  5. Oct 10, 2015 #4
    We have observed the light from distant stars being curved around the sun during eclipses.
  6. Oct 10, 2015 #5


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    Gold Member

    "Curved" is based on Euclidean Geometry. Space-time does not follow Euclidean geometry, it follow Riemann geometry and objects naturally follow Riemann straight lines, called geodesics, in space-time. From the reference point of Euclidean geometry, these straight lines appear curved although in their own frame, they are straight lines.

    As an analogy, think of a straight line on the surface of the Earth. This forms a curve (specifically a circle).

    Gravity causes things to follow geodesics so when light goes close to a massive object such as a star or a galaxy, it follows a geodesic, which in Euclidean terms appears curved.
  7. Oct 10, 2015 #6


    Staff: Mentor

    All tidal effects are evidence of spacetime curvature, including the fact that satellites in free fall can accelerate relative to each other.
  8. Oct 10, 2015 #7


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    Science Advisor

    Experimenta confirm GR to a high degree of precisiom, and GR describes gravity as spacetime curvature. But that is not 'evidence that spacetime is curved', only that it offers a good description. Newtonian gravity can also be described as spacetime curvature, and GR as a massless spin-2 theory.
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