On Tuesday, December 10, 2024 at 1:46:37 PM UTC-7 Brent Meeker wrote:
On 12/10/2024 1:33 AM, Alan Grayson wrote: On Monday, December 9, 2024 at 4:54:34 PM UTC-7 Brent Meeker wrote: On 12/9/2024 3:24 PM, Alan Grayson wrote: On Monday, December 9, 2024 at 2:01:28 PM UTC-7 Brent Meeker wrote: > > Nothing odd about dilation and contraction when you know its cause. > But what is odd is the fact that each frame sees the result > differently -- that the car fits in one frame, but not in the other -- > and you see nothing odd about that, that there's no objective reality > despite the symmetry. AG The facts are events in spacetime. There's an event F at which the front of the car is even with the exit of the garage and there's an event R at which the rear of the car is even with the entrance to the garage. If R is before F we say the car fitted in the garage. If R is after F we say the car did not fit. But if F and R are spacelike, then there is no fact of the matter about their time order. The time order will depend on the state of motion. Brent Since the car's length can be assumed to be arbitrarily small from the pov of the garage, why worry about fitting the car in garage perfectly, and then appealing to difference in spontaneity to prove no direct contradiction between the frames? It seems like a foolish effort to avoid a contradition, when one clearly exists. AG What's the contradiction? The contradiction is precisely this; assuming the initial rest state is that the length of the car is larger than the length of the garage, we get the *car* *never fitting* in the garage from the pov of the car, and the *car* *fitting* in the garage from the pov of the garage. The car can't fit *and* not fit in the garage. You think that because you have not carefully defined "fit", which does require reference to simultaneity. I defined "fit" to mean the car's length in any frame is *less* than the garage's length. AG The former result is easy to see, since the car's motion shrinks the garage's length, so the car, initially longer than the garage, can never fit inside the garage. Within the cars reference frame. Yes. AG The latter result follows from the fact that from the pov of the garage, the car's length shrinks, and for a sufficient velocity, it will shrink enough to fit in the garage. Further, the issue of simultaneity is a non-issue, No it is the essential issue. The car (or the garage) don't actually undergo some physical shrinkage. Yes. It's all about appearances, or so it seems. And yet, physicists claim the LT gives the actual measurements in one frame, using the measurements in another frame. AG If they did they wouldn't keep their dimensions in their own frame. So it is a question of measurement and simultaneity. Why then do physicists agree that the distance to Andromeda will be immensely shortened if a traveler's velocity is close to c? Never a mention of simultaneiry in this case. AG Brent since measurements of the front and back end of the car occur in the car's frame, and since the car never fits in the garage, such measurements can never be made when the car perfectly fits in the garage, or even loosely, since this condition never occurs. In summary, I think I've done for relativity, what Bertrand Russell did for Cantor's set theory; proving the existence of a contradiction. AG Brent -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/everything-list/a7b7ea97-b9a7-4d97-b85d-1feaec065d6cn%40googlegroups.com.
