On Tuesday, January 28, 2025 at 9:01:14 PM UTC-7 Jesse Mazer wrote:
On Tue, Jan 28, 2025 at 8:54 PM Alan Grayson <[email protected]> wrote: On Tuesday, January 28, 2025 at 2:56:32 PM UTC-7 Brent Meeker wrote: On 1/28/2025 6:49 AM, Alan Grayson wrote: I figured you'd jump on my word "separation". You have no idea what I mean? Of course, events with different coordinates are separated in a physical sense. Otherwise they'd have the SAME coordinates! But separated wrt spacetime events means no causal connections; whereas timelike events DO have causal connections. Of course, you know this, so please stop splitting hairs to make an argument. As for relative velocity, if you don't know what I mean, then you don't know what the v means in the gamma function. Again, stop splitting hairs. Oh, about GPS, I will look up this issue, but I was informed of it from a Ph'D in physics from Brent's Ph'D alma mater, University of Texas at Austin. It's surely NOT a distraction if it establishes that results in SR are physically real, not just appearances. AG There's an unfortunate but common confusion. The un-intuitive aspects of special relativity are physically real, but not it the sense that they happen to the moving object. If SR predicts length contraction, is the object is really shorter? (1) It's really shorter in the reference frame where it's moving. (2) It's not shorter in it's own frame. And (3) it's a different degree of shorter in other reference frames where it is moving with different velocities. Just looking at (2) people assume that it means (1) and (3) are just appearances. What's true is that *the contraction, relative to things in some reference frame, with respect to which it's moving, is real. *Brent *It's a baffling result. The LT doesn't tell us what will be MEASURED in a moving target frame being observed from a rest frame wrt length contraction and time dilation, so the result is just an APPEARANCE from the pov of the rest frame; and yet, from the pov of GPS clocks, these effects are real and measureable. This was the conclusion I argued, which is why I referenced the GPS clocks. * Brent's comment wasn't saying there was any disagreement between what coordinates the LT predicts for a given frame and what is really true (or really measured) in that frame, just like I wasn't saying that (see my last response above). You're really deluding yourself by rushing to read every explanation people give you as confirmation of your pre-existing fixed opinions. Jesse IMO you're deluding yourself in one important respect; your insistence that the results of the LT from the pov of some rest frame predicting length contraction in a frame moving wrt to it, can be measured in that moving frame; other than a no-contraction of length of some body at rest in that previously considered moving frame, which has zero length contraction (and zero time dilation) since the gamma factor applicable in that frame is equal to 1. So we're both correct from different points of view, but you were mistaken to ignore my comments about GPS. Also, to be candid, I don't appreciate your comment that I am rushing to accept an opinion that confirms my pre-existing fixed opinions. You like to focus on coordinates, but the fact is you were mistaken in claiming the LT makes a measurable prediction of what a source frame predicts. It does in the GPS case, but not in the case of what a target frame predicts internally. AG -- 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/3f8c6910-2951-4f35-93d4-62e733ee0883n%40googlegroups.com.
