On Thursday, January 30, 2025 at 7:59:32 AM UTC-7 Jesse Mazer wrote:
On Thu, Jan 30, 2025 at 9:16 AM Alan Grayson <agrays...@gmail.com> wrote: On Thursday, January 30, 2025 at 6:48:21 AM UTC-7 Jesse Mazer wrote: On Thu, Jan 30, 2025 at 12:51 AM Alan Grayson <agrays...@gmail.com> wrote: On Wednesday, January 29, 2025 at 6:52:47 PM UTC-7 Brent Meeker wrote: Whooo! Hoooo! Brent Another fool who doesn't get it? Another fool who can't think out of the box? Jesse claims that the LT preserves what it predicts for local events AND, according to his lights, using the LT it can be shown that lengths are EXPANDED. OTOH, it's universally predicted that lengths are CONTRACTED under the LT. No, it's universally predicted that length in a frame where an object is *in motion* (coordinate-motion using the term I coined in my previous comment, to distinguish from your alternate non-standard usage which I called 'designated-motion') is contracted relative to that object's "proper length" in the frame where the object is *at rest* (coordinate-rest), the L in the length contraction equation is always stated to be the proper length. So, if you use the LT to transform FROM the frame where the object is in motion (coordinate-motion) TO the frame where the object is at rest (coordinate-rest), treating the coordinate-motion frame as what you call the "source frame" and the coordinate-rest frame as what you call the "target frame" for the LT, in this case the length should be contracted in the source frame and larger in the target frame, *So, after our exhausting discussion, you still have no clue what I meant by source and target frames.* So "source frame" doesn't just mean the frame whose information we are given to start with (i.e. given coordinates values of length/velocity etc. for the objects we are analyzing) before applying the Lorentz transform to predict coordinates in the "target frame", i.e. it's not just that source=unprimed and target=primed in your description of the LT as giving us x-->x' and t-->t'? If that's not what you meant by "source" and "target", fine, but that's just a linguistic matter, you can delete all references to "source frame" and "target frame" in my comment above and change it to "starting frame" and "predicted frame" or whatever terminology you want to use for this; it changes nothing about the substantive point I was making. * I never said anything about a LT from a frame where the object is in motion. I alway stated I was transforming FROM a rest frame to a moving frame.* But you made a big deal of the fact that a ruler isn't measured as contracted in its own frame (and a clock isn't measured as running slow in its own frame), claiming this shows a divergence between what is PREDICTED by the LT and what is MEASURED. If you aren't actually using the LT to make PREDICTIONS about what should be true in the ruler's own frame (the frame where the ruler is in a state of coordinate-rest), i.e. using the ruler's frame as what I called the 'predicted frame', then how can this example be used to show a divergence between LT predictions vs. measurements? * Is there any textbook which makes your claim? I've never seen it, or heard about it, or hinted about it, and for this reason I ignored your mathematics. AG* I don't know that any textbook would go to the trouble of saying something like "the length of an object may be larger in the primed frame than the unprimed frame when you use the Lorentz transform to go from unprimed to primed", but I promise you that no textbook will say anything like "applying the Lorentz transformation to go from unprimed to primed always results in the length of any object being shorter in the primed frame than the unprimed frame". The only real reason to say something like the former would be to dispel a misconception like the latter, but I doubt this is a common misconception, I've talked to plenty of people who are confused about relativity on various forums over the years and never come across this idea of yours. If I looked around a bit I could probably find numerical examples in textbooks where just looking at the coordinates they give for some object in the unprimed vs. primed frame (or whatever notation they use to distinguish coordinates in the 'starting frame' from the 'predicted frame'), you could verify that the object was longer in the primed than it was in the unprimed. *Since the primed frame is the moving frame, if that were true, then SR wouldn't predict length contraction! AG* Would that satisfy your request for a textbook citation, or are you looking exclusively for a general verbal statement like the one I imagined above? 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 everything-list+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/everything-list/b5a56588-82b5-431a-82ee-650b561d7795n%40googlegroups.com.
