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If gravity bends light, how do we know we're not looking at the same old light going round and round in circles?

I've been musing over this for years but never thought of putting it on here. Happily, I came across Jah Kable's post suggesting the same thing. His conversation was closed though, but I don't think the question was answered. The question is; if light can be refracted by a strong gravitational field, black hole, sun, etc. then given enough objects in its path, could it not be slingshot all over the universe? If this is true, all the stars we can see at night might be (have once been) in a radically different position to where we see them now. We might even be seeing light from the same star in two places, or more. Imagine light is a ribbon strewn around the universe, twisted round gravitational objects. If that ribbon happened to pass by Earth more than once, we'd count it more than once in our sky, and each time it would look a different age and as if it were coming from a completely different direction.
There must be someone who can calculate whether this is possible or not! Trouble is, how would we know which objects are (were) real and therefore capable of bending the light and which are the resultant image of light that's already done umpteen laps of the cosmos?! It's bending my head, I know that much!

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    Jun 26 2013: RE: "If gravity bends light." It seems like a bad idea to challenge Einstein about Physics, but what the heck, here goes. Is the light from an electric lamp a focused flashlight-like beam? No. Unless focused by a lens light never travels in the form of a beam. Light travels omnidirectionally thus the lamp fills the room with light. How do you "bend" something which is omnipresent like the light from the lamp?
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      A wal

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      Jul 7 2013: Yes it expands in a sphere in flat space-time and in other shapes if the space-time is curved due to gravitational acceleration.
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        Jul 7 2013: Say what? How can there be a sphere in flat space?
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          A wal

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          Jul 7 2013: If the space-time is flat then the light will expand in all directions at the same rate, which makes an expanding sphere with the light source at the centre. If the space-time is curved then the light will move at the same speed in all directions but not at the same rate in all directions from a non-local perspective because time dilation and length contraction will cause distance in that direction to decrease (that's what curved space-time means), so you get a warped bubble of expanding light.
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        Jul 7 2013: RE: "If the space-time is flat then. . . ". Say what? How can there be a sphere (3D) in flat (2D) space?
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          A wal

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          Jul 7 2013: No, space-time is four dimensional (at least), whether it's flat or not. You're misunderstanding slightly what flat and curved means in this context. Flat simply means free of gravitaional acceleration in gr and curved means it isn't. Space-time is curved towards mass, which is another way of saying that gravity is a shortening of the distances in space and time (length contraction and time dilation) and the effect falls off as a inverse square of the distance. In zero dimensions it would be infinite, in one it wouldn't weaken with distance, in two if you double the distance it would be halved, and in three spactial dimension it's an inverse square (if you double the distance it's devided by four). It's simply the way it spreads out and becomes more difuse as it covers a larger volume.
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        Jul 7 2013: RE: "No, space-time is four dimensional. . . ". Do you deny that Cartesian Coordinates apply to this matter? A point in 2-D space can be located with an X (Left/Right) and a Y (Up/Down) coordinate. A Z (Above/Below the 2-D Plane) coordinate becomes necessary if locating a point in 3-D space.
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          A wal

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          Jul 8 2013: No of course I don't deny that. What does it have to do with this?

          The point is that in flat space-time all observers will agree on the distances between objects and in curved space-time they won't. If an observer draws a grid of squares in one flat pain and then does the same at a right angle to it they would get a three dimensional grid of cubes and in flat space-time all observers would agree. They'd all say they were all cubes, but that's not true in curved space-time. If an object close to a gravitational source did this then an object further away from it would see the same grid as warped because the distance in space-time is shortened for the object closer the mass, so they'd also be moving through time at a slower rate compared to the further object, but the closer one wouldn't notice anything unusual because it's relative.

          Distances aren't absolute. Observers measure different distances in the same space and time depending on the frame of reference. Space and time aren't a fixed background. They're an interconnected and dynamic background that are defined by the objects in it and measured differently by different observers depending on their point of view, and no-one is more or less right than anyone else. They're all right from their own perspective. Pretty isn't it.
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        Jul 8 2013: RE: "No of course I don't deny that. . ." Sorry, A wal, it's like we are speaking two different languages. I do not understand what you are saying about 3-D entities existing in 2-D space. But you say we all right in our own perspective, so I see no reason to debate. We are all right! Thanks for your time. Keep learning.
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          A wal

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          Jul 8 2013: I'm going to try explain it more clearly. Feel completely free to not reply to this post if you've had enough, I'm doing it for myself and for anyone reading this thread who might be interested. Please don't think I'm being condisending. I know that it can hard to get your head round this if you're not used to thinking in those terms and I'm trying to simplify and condense something that is unlike anythink we're used to in every day life, but it is actually very simple. I'm not trying to show off or anything by saying that. It really is simple, but it's sometimes very difficult for us to rap our heads around a concept that our normal lives haven't conditioned us to understand.

          I never said in two dimensional space. I think the problem is still that you're thinking flat means two dimensional. Flat in this context is how people normally think of space and time, ie every observer agrees on the distances between objects and the passage of time moves at the same rate for everyone. Curved means that there's a mass and observers closer to that mass measure distances between the same objects as shorter than those who are further away from the mass and also observers closer to the mass measure time moving at a slower rate, so those closer to a mass will appear to be moving through time at a slower faster rate from the perspective of a more distant observer and those further away will appear to be moving through time at a faster rate from the perspective of an observer closer to the mass. One very pretty way of describing this is objects following straight paths through curved space-time. I hope that helps a bit.

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