Jesse, It's not clear to me what you mean by, "in every coordinate system the time-coordinate of A = the time-coordinate of B. Are you actually disagreeing with that (please answer clearly yes or no)".
The way I understand that the answer is clearly NO. The whole idea of relativity is that the time coordinates (clock times) of A and B are NOT in general the same in either A nor B's coordinate systems, or any other coordinate system. And I did answer your crossing tapes example in detail showing how it is not relevant for p-time. I'm beginning to wonder if you actual read my posts... Edgar On Sunday, February 9, 2014 12:13:53 PM UTC-5, jessem wrote: > > > > On Sat, Feb 8, 2014 at 6:55 PM, Edgar L. Owen <[email protected]<javascript:> > > wrote: > > Jesse, > > The ages are the only 'real' clocks here because they are not arbitrary > but real and actual and cannot be reset. They show different clock times in > the same present moment. All other clocks are arbitrary. > > I don't know what else I can add to this. I did address all of your > questions whether or not you like my answers... > > > No you did not, because my question had nothing to do with what clock you > consider "real", it was just about how things are defined in relativity > theory. There is no clear answer above to the question I actually asked in > the post you were responding to, namely: > > "in every coordinate system the time-coordinate of A = the > time-coordinate of B. Are you actually disagreeing with that (please > answer clearly yes or no)" > > And note that I specifically added the qualification "Keep in mind that > we were talking about what's true according to the definitions of > coordinate time in relativity, this question has nothing to do with > anything not part of relativity theory like p-time, nor is it asking > whether you *approve* of the definitions used in relativity." So, can you > please give me a yes-or-no answer to the question above, under the > understanding that we're just talking about coordinate time as it's defined > in relativity and not any other notion of time which you may feel is more > "real"? > > Then I also discussed the perfect point-by-point analogy between the twin > paradox scenario and the measuring-tapes-which-cross-at-two-points > scenario, and asked another yes-or-no question: > > "I know that in some conceptual way you don't think a spatial scenario can > be analogous to one involving time, but can you point out any specific > measurable, quantitative facts about the twin scenario that don't have a > direct analogue in measurable, quantitative facts in the measuring-tape > scenario? As usual this is not meant to be a merely rhetorical question, > please answer yes or no (and if "yes" point to a specific measurable > quantitative fact in the twin paradox that you think lacks an analogue in > the measuring tape scenario)." > > Can you please answer this as well? > > Jesse > > > > > > Edgar > > > > On Saturday, February 8, 2014 6:23:37 PM UTC-5, jessem wrote: > > > > On Sat, Feb 8, 2014 at 10:41 AM, Edgar L. Owen <[email protected]> wrote: > > Jesse, > > No, they do NOT have the same time coordinates in their respective frames > because their clocks read different t-values. > > > In the post you're responding to here I had another request for > clarification which you didn't answer: > > "in every coordinate system the time-coordinate of A = the time-coordinate > of B. Are you actually disagreeing with that (please answer clearly yes > or no), or are you just pointing out that the shared time-coordinate is > different in different systems, or that the shared time-coordinate will not > match the clock time for both of them?" > > Keep in mind that we were talking about what's true according to the > definitions of coordinate time in relativity, this question has nothing to > do with anything not part of relativity theory like p-time, nor is it > asking whether you *approve* of the definitions used in relativity. > > > > You simply cannot invent any frame that makes the actual difference in > their ages go away. > > > I didn't say anything about making the difference in ages go away. If when > they meet twin #1 is turning 30 and twin #2 is turning 40, then if event A > = (twin #1 turns 30) and event B = (twin #2 turns 40), in every coordinate > system A has the same time-coordinate as B, but they are really different > ages at that point. > > > > > All you are doing is trying to ignore the effect by assigning a new > arbitrary time to the meeting. That's fine but they are still really > different ages so in that sense they can never actually be at the same > clock time except by an arbitrary definition which ignores the fact of the > trip and thus refuses to address the whole point of the trip. > > > I have no idea what you think I am "refusing to address". Yes, they really > are different ages, I have never suggested otherwise--and they really are > those different ages at the same coordinate time as coordinate time is > defined in relativity (using local measurements on physical coordinate > clocks). You may not *like* that definition of "same time", but if you are > actually denying that what I am saying is true ACCORDING TO THE STANDARD > DEFINITIONS OF RELATIVITY, then you are misunderstanding something about > how relativity works. > > Speaking of refusing to address things, yet again you just drop the > subject of spatial analogues when I explain how every quantitative fact > about the twin paradox scenario has a directly analogous quantitative fact > in the measuring tape scenario. For example, as I mentioned, the fact that > the twins are the same age when they depart is analogous to the fact that > at the first crossing-point that the measuring tapes diverge from, they > both show the same marking (say, 0 centimeters) at that first crossing > point. We can also lay out these tapes on a piece of graph paper with > Cartesian coordinate axes drawn on, so that any point on any given tape has > a spatial coordinate as well as a measuring-tape marking, analogous to the > fact that any event on the twins' worldline has a coordinate time as well > as a clock time according to their own clock. > > I know that in some conceptual way you don't think a spatial scenario can > be analogous to one involving time, but can you point out any specific > measurable, quantitative facts about the twin scenario that don't have a > direct analogue in measurable, quantitative facts in the measuring-tape > scenario? As usual this is not meant to be a merely rhetorical question, > please answer yes or no (and if "yes" point to a specific measurable > quantitative fact in the twin paradox that you think lacks an analogue in > the measuring tape scenario). > > 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] <javascript:>. > To post to this group, send email to [email protected]<javascript:> > . > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/groups/opt_out. > > ... -- 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 post to this group, send email to [email protected]. 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