On Sunday, December 15, 2024 at 9:41:15 AM UTC-7 Jesse Mazer wrote:
On Sun, Dec 15, 2024 at 8:31 AM Alan Grayson <[email protected]> wrote: On Sunday, December 15, 2024 at 6:20:47 AM UTC-7 Alan Grayson wrote: On Sunday, December 15, 2024 at 5:41:54 AM UTC-7 John Clark wrote: On Sat, Dec 14, 2024 at 11:01 PM Alan Grayson <[email protected]> wrote: * > What bothers me is the disagreement between frames about fitness or not, and why the alleged lack of simultaneity resolves the apparent contradiction. AG * *In this thought experiment I think even you would agree that no matter how fast or slow the car is going there will always be times when the front of the car is in the garage, and times when the back of the car is in the garage; so the question of the day is " Is there any frame of reference in which those two events occur SIMULTANEOUSLY?" Einstein's answer is "yes", provided the car is moving fast enough. And as proof that Einstein's answer was correct, in this thought experiment, above a certain speed, there is NO frame of reference in which there is a car shaped hole in the back door of the garage. * *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* No. Above a certain speed, since the car is length contracted from the pov of the garage frame, the car will fit in the garage, and waiting some time, then being in a different reference frame, it could hit the back door. AG But the real question is this; if from the pov of the car frame, there is a v such that the car never fits in the garage for this v and greater, why is it claimed that lack of simultaneity between frames solves the problem, since we're only considering simultaneity in garage frame where the car fits? AG Do you understand that when people talk about the relativity of simultaneity in the context of the car/garage problem, they are referring not just to events which are actually simultaneous in some frame, but also the fact that different frames can disagree about the time-ordering of events with a spacelike separation (i.e. neither event is in the past or future light cone of the other event)? The events A and B I was talking about earlier are not simultaneous in either the car frame or the garage frame (at least not with the numerical values for rest lengths and relative velocity given by Brent), but they happen in a different order in the two frames, and the relativity of simultaneity is key to understanding how that's possible, in Newtonian physics where all inertial frames agree about simultaneity there could be no disagreement about the order of any events. Jesse What I understand is that from the pov of the garage frame, the car's length is contracted so can fit in the garage. And, of course, "fit" requires simultaneity of the car's endpoints. This seems sufficient to solve the problem. But the so-called explanations involve another frame where simultaneity fails. So, I was wondering; why bring in a second frame, and that simultaneity fails in this other frame, to explain why the car will eventually fit in garage frame?. Anyway, I see my main problem all along has been my inability to *believe* that different frames can yield different measurements, even the case of a larger car fitting in an initially smaller garage. BTW, I still want to know if clocks in different frames can be synchronized, and if so, whether the synchronization persists. I appreciate your patience throughout this discussion. Are you the physics graduate of Brown University? AG -- 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/c9fab5d0-f11f-43d4-8cde-14ed5bef07e2n%40googlegroups.com.
