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BeardedTed
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I recently read in astronomy magazine about Gravity prob b and it findings, Can someone please explain Geodetic effect and how it proves relativity?
Thanks
Bearded
Thanks
Bearded
In that case, you should also urge Stanford and Kip Thorne to stop using it to explain the geodetic effect:Bill_K said:A.T., I'm sure your diagram is well-intentioned, but it is absolutely wrong, and anyone who has seen it is hereby requested to purge it from their minds!
It approximates the spatial geometry Schwarzschild (Flamm's paraboloid) as I explained here:Bill_K said:It is not true in any sense that the spacetime curvature surrounding a massive object is analogous to a cone.
The circumference of a circle around a big mass is also less than 2 pi * proper radius, according to Schwarzschild geometry.Bill_K said:While drawing a cone makes it easy to visualize, it is completely wrong. A cone is formed from a flat piece of paper by removing a section and pasting the remaining part together. What you are left with has an angular defect: its circumference is less than two pi.
Flamm's paraboloid doesn't have any angular defect?Bill_K said:And sure enough, a vector transported around the circumference will fail to come back to its original position for that reason. Such spacetimes are quite anomalous, although they have been considered for example in cosmic strings.
Schwarzschild does not have this property.
Only in the sense in which the rim of the cone is a "perfectly normal" circle. And yet there is an angular defect on that cone.Bill_K said:The surfaces r = const in Schwarzschild are perfectly normal two-spheres.
That is how I see it too. The spatial part is easier to visualize (with the cone diagram) hence it's OK to use it, and eventually mention that this explains 2/3 of the effect.bcrowell said:One expects both a geometrical precession (due to spatial curvature) and a Thomas precession.
Sam Gralla said:Is there a writeup (for people who know GR) of this claim that 2/3 of the effect is due the non-Euclidean relationship between radius and circumference?
Sam Gralla said:Is there a writeup (for people who know GR) of this claim that 2/3 of the effect is due the non-Euclidean relationship between radius and circumference?
I have to agree with Bill K that fundamentally the effect is local, and the diagram is pretty misleading in that sense. But I'm sure there's something behind it, if Kip is using it. It's tough to know how much to simplify when giving popular explanations.
The GeekGeodetic Effect is a phenomenon predicted by Einstein's theory of general relativity, which states that the rotation of a massive object, such as a planet or star, will cause the space around it to twist or warp.
The GeekGeodetic Effect is a direct result of Einstein's theory of general relativity, which describes how gravity is not a force between objects, but rather a curvature of space and time caused by massive objects.
No, the GeekGeodetic Effect is only noticeable in extreme situations, such as near extremely massive objects like black holes or rapidly rotating neutron stars.
The GeekGeodetic Effect was first proven through precise measurements of the orbits of Mercury and other planets, which showed that their orbits were affected by the curvature of space caused by the Sun's mass and rotation.
The GeekGeodetic Effect is important because it provides concrete evidence for the validity of Einstein's theory of general relativity, which has far-reaching implications for our understanding of the universe and the laws of physics.