@Thomas,
Quote:You get to pick your frame of reference in the beginning. But once you have, you need to be consequent about it. Once you picked the city's frame of reference, the cars are really moving. Once you have picked one of the car's frame of reference the city and the other car really move toward it.
I keep hearing this being said, but no one seems to have a sensible (consistent) answer to some obvious questions, to wit:
Take a situation where we have launched a rocket toward mars. The rocket is now halfway to mars, and is no longer accelerating--it is moving inertially.
Now some questions arise, such as:
1. If you (Thomas) "pick" the rocket, is it that (your arbitrary, subjective choice) which determines that it is "at rest?" If you (Thomas) "pick" the earth, is it that (your arbitrary, subjective choice) which determines that now (and only now) the rocket is "really moving?" Do you (Thomas) control, with your thoughts or choices, what "really" moves in the external world? Sounds solipsistic to me.
2. Let's say the rocket accelerated steadily for whole day, but then the thrust ceased and the rocket settled into "inertial motion." Does that (the cessation of acceleration) somehow serve
repeal the law of inertia? Does the rocket continue to move, even after the accelerating force ceases? Or does it suddenly, immediately, and automatically come to a complete stop?
I have noted your repeated claim that the "acceleration" is absolute in SR, but that the resulting motion is still "relative." I also note that you have provided no source or argument in support of that claim.
You also claimed, at one point, that it was only AFTER a dragster quit accelerating that one "entered the realm of SR" (or however you put it exactly), which seems to conflict with your claim that accelerating motion is relative. Furthermore, as I recall, you also said that both the driver and the people in the bleachers would perceive the car as partaking in accelerated motion, which again undermines your statement that such motion is "relative" (frame dependent).
I will finally note that such a claim (i.e., that accelerating motion is relative motion) is contrary to what physicists say, some of whom I have already cited to you on that point (by necessary implication), and with whom you said you agreed.
Do you have any other answer?