On Tue, Feb 11, 2014 at 7:46 PM, Jesse Mazer <[email protected]> wrote: > > "Instantaneously pause" has no frame-independent meaning in relativity, do > you disagree? If A and B are in relative motion, and unlike my example > above, B is *not* at the same point in spacetime as A when A turns some age > (say 60), then different frames disagree on what age B is "at the same > instant" that B turns 60. So if one frame said B was 48 at the same instant > A turned 50, and another frame said B was 75 at the same instant A turned > 50, then at what age should B's motion relative to A be "paused"? We don't > have an "objective instantaneous pause machine" that can settle the > question empirically, it has to be *our choice* when to subject B to a > sudden acceleration to instantaneously bring him to rest relative to A. > Again, do you disagree? >
Sorry, I got the numbers and letters a little mixed up here, the paragraph should read: "Instantaneously pause" has no frame-independent meaning in relativity, do you disagree? If A and B are in relative motion, and unlike my example above, B is *not* at the same point in spacetime as A when A turns some age (say 60), then different frames disagree on what age B is "at the same instant" that A turns 60. So if one frame said B was 48 at the same instant A turned 60, and another frame said B was 75 at the same instant A turned 60, then at what age should B's motion relative to A be "paused"? We don't have an "objective instantaneous pause machine" that can settle the question empirically, it has to be *our choice* when to subject B to a sudden acceleration to instantaneously bring him to rest relative to A. Again, do you disagree? -- 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]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
