harald says... > >On Jul 5, 4:18=A0am, stevendaryl3...@yahoo.com (Daryl McCullough) wrote: >> harald says... >> >> >Einstein explained how a paradox arose with the inception of GRT: >> >> It's athttp://tiny.cc/kz0uq >> >> I read the dialog, and I do not agree with your description of it, >>as a paradox of GR. The fact is, as I said, the "GR description" is >>actually not GR at all, it's SR being expressed in noninertial coordinates. > >That's wrong: SRT does not *have* such concepts as "induced >gravitational fields".
Yes, it certainly does. If you are in a rocket that is accelerating upwards, and you drop a ball, it will fall to the floor. That's true in Newtonian physica, and it's true in SR. That's all that is meant by an induced gravitational field.
>> The use of the term "gravitational field" is picturesque and suggestive, >> but nothing that Einstein says about interpreting the twin paradox from >> the point of view of the traveling twin is in any way dependent on >> Einstein's theory of gravity. > >Indeed it's not!
Then it's not GR. It's SR in noninertial coordinates. So you are mistaken in calling a paradox of GR, for two reasons: (1) It's not a paradox, and (2) it's not GR.
>That is well known - and it misses the point (again).
I think it is because you have not made it very well. I still have no idea what your point is.
I admit to mistaking your discussion about the General Principle of Relativity as a discussion about GR, the theory of gravity.
If your point is about the General Principle of Relativity (that the laws are covariant under generalized changes of coordinates), that has no physical content, and Einstein was mistaken to think otherwise. You can always rewrite the laws so that they are covariant.
However, I don't see how the twin paradox is a "consistency challenge" for the principle of relativity or for GR, the gravitational theory.
>1. I brought to your attention what history tells us about how the >clock paradox started for Einstein, information that was kept hidden >for the non-German speaking community for many decades >2. The information conflicts with what you "know" (what you learned >and believed for a long time) >3. From that you conclude that point 1 must be wrong.
I have no idea what you are talking about. I certainly have never made claims about history. My point is about the logical relationships among Special, General Relativity, and the twin paradox.