Quartile Posted September 28, 2007 Posted September 28, 2007 Would it be too much of a stretch to say that movement of a mass creates a 'hole' in spacetime? Sort of the same way that a baseball moving through a tank of water displaces water and creates a hole for it to move through?
timo Posted September 28, 2007 Posted September 28, 2007 I wouldn't even know which statement to overstretch to come to that interpretation.
timo Posted September 29, 2007 Posted September 29, 2007 I don't think it is. A typically-used analogy is that of a massive ball rolling on a rubber sheet. At the position of the ball, the rubber sheet is deformed due to the weight of the ball (let's ignore that the deformation is supposed to be the cause for gravity, not something caused by gravity working on the objects in it - it's just an analogy). The point is: Even though it's slightly deformed, there still is some part of the sheet below the ball - the ball does deform but not replace the sheet. This part of the rubber-sheet analogy holds true to the real theory. Objects are located in spacetime (perhaps see it as attached to some point or area of spacetime), they do not replace it. You are talking about interpretation. Interpretation naturally is arbitrary to some extent and generally you can interpret any physical effect/model/... however you want to (nature won't care, anyways). So I cannot definitely say "no, you can't interpret it this way". I can only tell you that I see no sensible or useful way to interpret any relativistic equation in the way of your "baseball in water"-example.
Country Boy Posted September 29, 2007 Posted September 29, 2007 Athiest's remark about "which statement ro oversteretch" was referring to your analogy being to a baseball in water creating "a hole for it to move through". That is also does not happen!
Quartile Posted September 30, 2007 Author Posted September 30, 2007 A typically-used analogy is that of a massive ball rolling on a rubber sheet. At the position of the ball, the rubber sheet is deformed due to the weight of the ball OK, so if the rubber sheet is 100m long and it takes this massive ball 5s to roll all the way across the 100m, wouldnt there still be deformation in the rubber sheet at 60m even when the ball is at 80m? In the 1s that it takes the ball to roll from 60m to 80m, the rubber sheet would not have time to return to its undisturbed position at 60m. Am I starting to make more sense? My original question about a mass MOVING through a three dimensional space and creating a sort of 'hole' in it is not a question that I ask in blind ignorance. I know that Im not very good at explaining myself thoroughly, and I apologize. Please bear with me!
Mr Skeptic Posted September 30, 2007 Posted September 30, 2007 Is what you are asking about akin to gravity waves? Deformations of spacetime specifically caused by moving matter? People are expecting those to exist.
Quartile Posted October 3, 2007 Author Posted October 3, 2007 Im thinking of gravity curving spacetime while the mass involved is moving through it. I understand the rubber sheet analogy, but space is three dimensional so you have to think of it as a stack of rubber sheets with the ball rolling in between the stack like a marble in a sandwich.
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