Le mar. 7 janv. 2025, 19:00, Alan Grayson <[email protected]> a écrit :
> > > On Tuesday, January 7, 2025 at 10:43:08 AM UTC-7 John Clark wrote: > > On Tue, Jan 7, 2025 at 9:35 AM Alan Grayson <[email protected]> wrote: > > *> I'm not denying simultaneity. But I do see it as irrelevant in knowing > whether the car fits or not.* > > > *Irrelevant?! Regardless of how long or short the car is or how long or > short the garage is or how fast or slow an observer is moving EVERYBODY > will agree that there was a time when the back of the car entered the front > of the garage, and everybody will agree there was a time when the front of > the car left the back of the garage, and everybody will agree there was a > time where both of the doors on the garage were closed, BUT they will > disagree if those three events occurred simultaneously. Those who think > they were simultaneous events will conclude that the car fit in the garage, > and those who think the events were not simultaneous will conclude that the > car did not fit in the garage. * > > *John K Clark See what's on my new list at Extropolis > <https://groups.google.com/g/extropolis>* > > > *Why cannot the car's endpoints be simultaneous without the car fitting? > After all, in any frame, all clocks can be synchronized to be simultaneous. > ISTM that the necessary requirement for fitting is the relative lengths of > the car and garage, and these lengths depend on the initial conditions, and > later on the car's speed, applying length contraction using the LT. I get > the same results as Brent just using length contraction and yet, according > to Quentin, I am downgrading the disagreement about simultaneity. The fact > is, it isn't needed to establish the apparent paradox. If you guys want to > blame someone, blame Einstein! AG * > AG, your persistence in misunderstanding the role of simultaneity is as impressive as it is flawed. Let me dismantle your latest deflections with precision. "The car's endpoints can be simultaneous without fitting" is nonsensical. To determine if the car "fits" in the garage, we are comparing two spatially separated events. Event A: The back of the car passes the garage entrance. Event B: The front of the car reaches or is within the garage exit. These events can only be declared simultaneous within a specific frame. Simultaneity is frame-dependent, and that is precisely why the disagreement about "fit" arises. You cannot simply claim the endpoints are simultaneous without specifying the frame—you would be discarding relativity altogether. Length contraction alone does not resolve the paradox. Your insistence on using length contraction as a standalone solution ignores the fact that length contraction is frame-dependent. In the garage’s frame, the car is contracted and can fit. In the car’s frame, the garage is contracted, and the car cannot fit. Without simultaneity to determine when and where the endpoints align, you are left with an ill-defined concept of "fit." Length contraction is a necessary condition for fit, but it does not address the sufficient condition, which requires simultaneity. "All clocks can be synchronized" is a red herring. Your claim that "all clocks can be synchronized in any frame" is irrelevant because synchronization only applies within that frame. Relativity of simultaneity ensures that different frames will disagree about what events are simultaneous. This disagreement is not a side issue—it is the heart of the paradox. Your approach downgrades simultaneity because you refuse to engage with it. By focusing solely on length contraction, you are willfully ignoring the role of simultaneity in defining "fit." Brent’s approach, even if it relies on the same math, acknowledges simultaneity as critical to resolving the disagreement. Your refusal to do the same is intellectual dishonesty disguised as simplicity. Blaming Einstein is ironic given your misuse of his theory. The tools to resolve this paradox—length contraction, time dilation, and the relativity of simultaneity—are all derived from Einstein’s theory of special relativity. If you are unhappy with the role of simultaneity, it is not Einstein you should blame—it is your own refusal to fully engage with his framework. Final Word. You are not solving the paradox; you are dodging it. Length contraction alone is insufficient without simultaneity, and claiming otherwise is either ignorance or bad faith. If you are unwilling to address this foundational aspect of relativity, you are not arguing physics—you are arguing for the sake of arguing. Either engage with the actual problem or admit you are out of your depth. > *8ys* > > > -- > 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/176a6fe9-5d63-4a2c-ad37-d97957e71012n%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/176a6fe9-5d63-4a2c-ad37-d97957e71012n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- 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/CAMW2kAq%2B1AMYf5Yu0Om2eXETS0arHVg4GEO1JZzqpLWO9rJjnA%40mail.gmail.com.
