Thank you all for the details on how proper acceleration is calculated. From this moment on, I am by [my] rule not permitted to speak further on the subject until I have learned to do the calculation for myself.
This will do it for me on this thread. I learned a lot. Hopefully I will show a bit...
Thank you for the further information. This gives a much different impression than you have given so far. Up to now, you have made it sound as though the act of selecting the coordinate system at the appropriate time is what causes the motion of the Earth.
[Edited to remove reference to an...
You have said that you can cause motion by choosing a specific coordinate system. I am asking questions about what happens when that specific coordinate system is chosen. You can't avoid answering the questions by attempting to use some other coordinate system(s).
I'll ask two simple questions...
The bolded text highlights our disagreement. You say that acceleration does not imply movement. I say that the definition of acceleration implies movement; by definition, there is no acceleration without movement.
As I understand your position, the distinction between coordinate acceleration...
My question is whether the resting rocket observer is compelled by any evidence to accept that he accelerated.
It's tough to satisfy everyone on the forum. I once said "force" unqualified, meaning a force that would cause acceleration as judged from an inertial frame, and was corrected for...
Back to the original scenario.
1. Prior to the firing of the rocket, if you select the specific coordinate system, do you make both the Earth and the rocket move, and in such a way as to maintain unchanged the distance between them?
If the answer to 1 is yes, please go on.
2. If you...
Is the argument for absolute acceleration compelling? The physical phenomenon that is indisputably present in all coordinate systems is the unbalanced force. The physical reality of the worldline path is not an indisputable fact in any coordinate system, as I understand the concept. The rocket...
Fiction to some degree perhaps. But there are surely degrees of fiction. Newton could point to specific massive bodies and specific distances between them to explain the cause of specific gravitational effects. That kind of detail is missing from the explanation for the behavior of the resting...
Yes to both points.
The universe as depicted by the observer in the resting rocket has a homogenous gravitational field of vaguely specified origin. That gravitational field is necessary to maintain the claim that the rocket is really at rest. The reality of this gravitational field is...
True, the physical content does not change in this example.
This is not true in the case of the resting rocket. In that coordinate system, no force acts on the Earth, yet it accelerates. And, an unbalanced force acts on the rocket, yet it does not accelerate. Both of these phenomena violate...
I don't assume anything with regard to which kind of observer can consider himself at rest. The concept was never of more than passing interest until I read Einstein's book Relativity. I didn't have any pre-conceived ideas going in.
I don't think that is true, as a matter of logic. "At rest"...
I'd like a yes or no answer.
After the resting rocket twin fires his engine and sees the Earth accelerate away, he eventually sees his target star approach. He can measure the distance to the star at intervals and verify that it is indeed getting closer. You have said repeatedly that the...
We began by discussing the absoluteness of proper acceleration in the context of the twin paradox. We proceeded to discuss why certain objectors (the one in Taylor & Wheeler, and myself) believe that their objection has not been dealt with. I ended by saying that I am satisfied that the twin...