On Monday, January 27, 2025 at 4:46:07 PM UTC-7 Alan Grayson wrote:
On Monday, January 27, 2025 at 1:15:05 PM UTC-7 Jesse Mazer wrote: On Mon, Jan 27, 2025 at 3:01 PM Alan Grayson <[email protected]> wrote: On Monday, January 27, 2025 at 12:54:57 PM UTC-7 Jesse Mazer wrote: On Mon, Jan 27, 2025 at 8:32 AM Alan Grayson <[email protected]> wrote: On Sunday, January 26, 2025 at 9:02:01 PM UTC-7 Jesse Mazer wrote: On Sun, Jan 26, 2025 at 10:23 PM Alan Grayson <[email protected]> wrote: On Sunday, January 26, 2025 at 9:13:54 AM UTC-7 Jesse Mazer wrote: On Sun, Jan 26, 2025 at 1:54 AM Alan Grayson <[email protected]> wrote: On Saturday, January 25, 2025 at 11:25:53 PM UTC-7 Brent Meeker wrote: On 1/25/2025 10:13 PM, Alan Grayson wrote: On Saturday, January 25, 2025 at 9:06:18 PM UTC-7 Brent Meeker wrote: On 1/25/2025 6:34 PM, Alan Grayson wrote: On Saturday, January 25, 2025 at 6:47:22 PM UTC-7 Jesse Mazer wrote: On Sat, Jan 25, 2025 at 8:07 PM Alan Grayson <[email protected]> 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 Jesse; it's the last two of Brent's sentences that I find ambiguous. What does he mean? What about them do you find ambiguous? He's just saying that if there's a spacelike separation between the events F and R (as there was in his numerical example), then you can find a frame where R happens after F (as is true in the car frame where the car doesn't fit), and another frame where F happens after R (as is true in the garage frame where the car does fit). *What does he mean by "But if F and R are spacelike, then there is no fact of the matter about their time order."? (What you wrote above?) * Brent writes > Yes. Just what Jesse wrote above. It means the two events were so close together in time and distant in space that something would have to travel faster than light to be at both of them. *More important I just realized that in the frame of car fitting, the events F and R aren't simultaneous, so how does one apply disagreement on simultaneity when one starts with two events which are NOT simultaneous? AG* Brent writes > That's why you should talk about events being spacelike...the relativistic analogue of simultaneous. *I'd like to do that. BUT if the Parking Paradox is allegedly solved by star**ting in the garage frame where the car fits, the pair of events which define fitting are not spacelike since they occur at different times! * You didn't read the definition of "spacelike" that I wrote above. You want everything fed to you in tiny bites of knowledge which you forget eight lines later, so the questions start all over again. Brent *I read it, but didn't like it. Big difference. Maybe you should stop trying to read my intentions. You may be smart, but reading my intentions is way above your pay grade. How could two events with the same time coordinate be referred as "so close together". Moreover, in all discussions of solutions to the paradox, events that are simultaneous in one frame, are shown not simultaneous in another frame. This being the case, the two events of the car fitting in garage frame are simply NOT simultaneous! Also, Jesse seems to be referring to different events than the ones you refer to. So there's a muddle IMO. As a teacher, your preferred method is to intimidate students. Grade now D+. AG * Why do you think I am referring to different events? I referred to the same events F and R that Brent did (F is the event of the front of the car coinciding with the garage exit, R is the event of the rear of the car coinciding with the garage entrance). If you don't like Brent's verbal explanation, I also gave you a mathematical definition of "spacelike separation" in two recent posts on the "Brent on Parking Paradox" thread at https://groups.google.com/g/everything-list/c/QgVdhXi3Hdc/m/KC2lIKyrDQAJ and https://groups.google.com/g/everything-list/c/QgVdhXi3Hdc/m/FF7TpbG-DQAJ -- "If you know the distance x and time interval t between the two points/events in the coordinates of any inertial frame, to say they are spacelike separated just means that x > ct (and an equivalent definition is that neither point is in the past or future light cone of the other one)". Since I explicitly referred to a time interval t between the two events, if you had paid attention to that you would have known not to say "the pair of events which define fitting are not spacelike since they occur at different times". Jesse *Yes, you defined spacelike separation, but without specific numbers for events, one cannot automatically claim two events are spacelike separated. Same goes for fitting in garage frame. I wasn't sure that all pairs of events in garage where car fits are spacelike separated. And sometimes I haven't caught up with your posts so I seem like I can't remember. And occasionally I do forget what someone posted. AG* I was responding to your statement "the pair of events which define fitting are not spacelike since they occur at different times", one doesn't need any specific coordinates to see that this statement is wrong because it suggests spacelike separated events can't occur at different times. If you hadn't read my definition or didn't remember it, fine. *I meant above that I needed all the coordinate values to determine if two events are spacelike separated; the time coordinates are not enough. AG * I gave you both x and t coordinates for F and R in my last message, see below. Or when you say "I meant above that I needed all the coordinate values", is "above" referring to your original comment "the pair of events which define fitting are not spacelike since they occur at different times", i.e. are you saying that when you wrote that, what you really meant was just that Brent hadn't provided the coordinates or R and F? Or would you acknowledge that when you wrote that you were misunderstanding the notion of spacelike separation? I was referring to my original comment. I didn't misunderstand what spacelike separation means. I don't recall what Brent posted. AG Then why did you make the definitive sounding statement "the pair of events which define fitting are NOT SPACELIKE since they occur at different times", rather than something more open-ended like "you haven't given the coordinates for the pair of events which define fitting, so although those events could be spacelike separated you haven't given enough info to demonstrate that"? *I was left with the last recollection / impression when you gave an example of simultaneous event which were spacelike separated. Then when I considered it further, I realized I needed all the coordinates to make that assertion. As for Brent, as I recall, he didn't give any coordinates, just the claim as an approximation. FWIW, the car parking paradox reminds me of the S cat scenario, where S proved that a superposition of alive and dead when the box is closed, cannot imply the cat is alive and dead simultaneously. In a post here, I showed why a superposition cannot be interpreted that way because of the infinitely many bases for a system in Hilbert Space. In this problem, on relativity, although I accept that different frames can make different measurement due to relative motion,such as for E and B fields, the same car that can fit and not fit, albeit at different times, seems a bridge too far. If I am right, I can't say exactly what's wrong with relativity. It's a work in progress. AG* it seems like you're just coming up with an interpretation in retrospect to avoid acknowledging you were wrong, *I didn't use the word "wrong", but I clearly corrected my error. Why isn't that enough for you? AG* rather than accurately remembering/describing what you meant at the time. (In general you never seem to acknowledge you were wrong about any significant assertion you make concerning relativity, like with your earlier claim the LT sometimes give different coordinates than what's actually measured in a given frame, which you seem to have just dropped rather than acknowledging any flaw in your argument) *On that point, I am still not convinced the LT does what you claim. I was planning to come back to that issue. I have to review why I thought that. AG * *I recall my doubts about your interpretation of the LT. It has to do with length contraction and time dilation. The LT gives a result which isn't reproduced in the target frame of the transformation. IOW, an observer in the target frame doesn't notice (or measure) length contraction and time dilation. AG* 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/2db8bb5c-c641-4a73-87be-fe1854664799n%40googlegroups.com.
