On Fri, Jan 24, 2025 at 8:53 AM Alan Grayson <[email protected]> wrote:
> > > On Thursday, January 23, 2025 at 11:46:46 PM UTC-7 Brent Meeker wrote: > > That's exactly what my diagram shows. Didn't you look at it? > > Brent > > > Sure, I looked at it but I prefer text, and I forgot you're a deaf mute. > And NO, I didn't know that frame transformations can invert time > relations. Let's forget it. I forgot you prefer your riddles. Grade C- . AG > The point that the LT can change the order of events with a spacelike separation is one I also talked about many times on the previous thread, for example at https://groups.google.com/g/everything-list/c/vcrAzg4HSSc/m/knVuCxHFAwAJ where I wrote: "Because as you previously agreed, the question of whether the car fits reduces to the question of whether the event A = back of car passes front of garage happens before, after, or simultaneously with the event B = front of car reaches back of garage. Since these events have a spacelike separation in both Brent’s and my numerical examples, in relativity different frames can disagree on their order, that’s the whole reason we say frames disagree on whether the car fits." Likewise in https://groups.google.com/g/everything-list/c/gbOE5B-7a6g/m/MwKDuJM-AQAJ where I wrote: "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." Brent has made this point in the past as well, for example at https://groups.google.com/g/everything-list/c/gbOE5B-7a6g/m/WcxkopmjAAAJ where he wrote: "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." Did you really not remember any of these discussions, or did you just misunderstand the meaning of "invert time relations" to be something different than the idea that two events A and B with a spacelike separation can have a different time-order in different frames? Jesse -- 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/CAPCWU3J4mz5ex9Usd7keZxDG0F1x1vU9%3DOrpuhZfKXGzpO%3D0mw%40mail.gmail.com.
