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I was wondering what are the distances, speeds, energies etc. were relativity can cause notable differences.
I am asking because I heard in a TV that for a distance from here to Jupiter for example, euclid geometry calculations start to deviate from reality. I don't know if he reffered to distances in the universe general, or for distances within a certain gravitational field (in our case, the Sun's) I am not sure if this is correct or wrong. In case this is valid, we should have orbit modifications for spacecrafts sent to Jupiter, for example. Do we have any such corrections? |
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Euclidian geomtry has no problem with the universe so long as travel time is instanteous and we see all objects exactly where they really are. We don't, of course. Light travels at a finite speed and so we see objects as they were in the past. Even close objects such as Jupiter. In fact calculating where Jupiter 'should be' compared to where we see it was one of the ways in which the speed of light was first calculated.
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"Patriotism is supporting your country all of the time... and your government when it deserves it." - Mark Twain |
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I think you're thinking of the ISS/shuttle or something else in LEO.
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"I have a cunning plan that cannot fail." S. Baldrick |
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I think the comment: "for a distance from here to Jupiter for example, euclid geometry calculations start to deviate from reality. ", might be based on the time-space curvature that occurs in gravity fields, as predicted by General Relativity. The Sun's gravity field is not that strong to cause big differences for small paths, but if we integrate/add these differences for a path from the Sun to Jupiter, these differences might start to become notable. Could this be the explanation of what I heard in TV, or is this just nonsense? |
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If the geometry of the universe was closed then the angles of a triangle would add up to more than 180 degrees and if open, less than 180 degrees. Only if the universe is flat (Euclidean) would they add up to 180 degrees. I think this is still an open question (if you'll excuse the pun). Maybe this is what they were referring to. |
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) It even gets a mention in Hawking's "A brief history of time", IIRC. Didn't spot the incorrect altitudes though. Oops. ops: It is astonishing though, that to provide the current level of accuracy, you have to correct for what was once considered a pretty exotic effect. |
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