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Dale
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I don't know how it is possible to corroborate something that doesn't exist.harrylin said:Builder refers to several follow-ups in the literature that corroborate Einstein's calculation.
I don't know how it is possible to corroborate something that doesn't exist.harrylin said:Builder refers to several follow-ups in the literature that corroborate Einstein's calculation.
It's certainly possible to verify if a calculation method that is claimed to work indeed works. I provided two references that verified that Einstein wasn't bluffing, for those who hold that Einstein's description is too vague to verify.DaleSpam said:I don't know how it is possible to corroborate something that doesn't exist.
In addition to the other answers: it's not generally relevant what the person feels, what matters are velocity and gravitational potential. In the first space travel "twin example" by Langevin, the traveler didn't even feel any force at turnaround as he was traveling in a sling shot around a star.Jimster41 said:[..] The question of "which twin ages slower" is determined by the proper acceleration. The traveling twin experiences proper acceleration (because he's on the rocket and is physically subject to the non-gravitational force applied by it). Proper acceleration causes length contraction and time dilation and that's why he ages slower. [..]
harrylin said:Neither Einstein, nor Moller, nor Builder brought them up in this context.
harrylin said:for those who hold that Einstein's description is too vague to verify
Jimster41 said:How is the mass/energy component of the GR description of the "virtual field", accounted for in the SR flat s.t. non-inertial coordinates description?
stevendaryl said:GR doesn't say that "gravitational fields" have mass/energy as the source. It says that the curvature tensor has mass/energy as the source. The "induced gravitational field" that results from switching to a noninertial reference frame has zero curvature, so it has no mass/energy associated with it.
Jimster41 said:There is some energy required to curve the world line of the traveling twin through flat space-time?
PeterDonis said:Curvature of a worldline is not the same as curvature of spacetime. You can have a curved worldline in flat spacetime, and a straight (geodesic) worldline in curved spacetime. They're two different concepts.
It is true that the traveling twin must have some means of curving his worldline (accelerating) in order to change course, such as a rocket, and this requires energy, and energy can in principle curve spacetime. However, the standard twin paradox scenario assumes that the energy required for the traveling twin to change course is too small to have any significant effect on the geometry of spacetime, so spacetime can be assumed to be flat. As a practical assumption, this works very well for all ordinary objects; to significantly curve spacetime, you need a very large object, like a planet or a star.
Jimster41 said:what physical thing is happening to the "traveling twin" in a single acceleration step
Jimster41 said:which is dependent on energy, by which time dilation and length contraction occur
As long as the energy the traveling twin needs to expend to curve his worldline is small enough, it will have negligible effect on the spacetime geometry. But SR doesn't explain why this is true; SR just assumes it (and assumes that we are only dealing with situations where all the energies are small enough). To explain why energies that are small enough don't affect the spacetime geometry, you need GR; the Einstein Field Equation, which tells you how much spacetime curvature is produced by a given amount of energy, is part of GR, not SR.Jimster41 said:that is not a local space-time "bending" moment
They made a lot of assumptions in the German-to-Math translation. I am not saying that their assumptions are bad ones, but I still hold that his description is too vague to verify.harrylin said:It's certainly possible to verify if a calculation method that is claimed to work indeed works. I provided two references that verified that Einstein wasn't bluffing, for those who hold that Einstein's description is too vague to verify.
Clearly Einstein did. That is what he was referring to when he said "gravitational field". I showed in his technical paper where he stated that explicitly, but even just his pop-sci paper makes it clear from the way he describes the properties of the gravitational field.harrylin said:Neither Einstein, nor Moller, nor Builder brought them up in this context.
With this I think it is time to close this thread. This now primarily about Einstein's word-choice and not about physics, and this type of language is deliberately unhelpful. Let's keep future threads to actual physics and not semantics.harrylin said:there remain fictional terms in his description with magical effects.