On Friday, October 25, 2024 at 4:58:47 PM UTC-6 Brent Meeker wrote:
On 10/25/2024 2:49 PM, Alan Grayson wrote: On Friday, October 25, 2024 at 11:34:13 AM UTC-6 Jesse Mazer wrote: On Fri, Oct 25, 2024 at 5:44 AM Alan Grayson <agrays...@gmail.com> wrote: On Friday, October 25, 2024 at 2:44:06 AM UTC-6 Brent Meeker wrote: On 10/25/2024 1:36 AM, Alan Grayson wrote: On Thursday, October 24, 2024 at 11:07:18 PM UTC-6 Brent Meeker wrote: On 10/24/2024 5:46 PM, Alan Grayson wrote: On Thursday, October 24, 2024 at 1:30:32 PM UTC-6 Brent Meeker wrote: Here's how a light-clock ticks in when in motion. A light-clock is just two perfect mirrors a fixed distance apart with a photon bouncing back an forth between them. It's a hypothetical ideal clock for which the effect of motion is easily visualized. These are the spacetime diagrams of three identical light-clocks moving at *+*c relative to the blue one. *Three clocks? Black diagram? If only this was as clear as you claim. TY, AG* *You can't handle more than two? The left clock is black with a red photon. Is that hard to comprehend? Didn't they teach spacetime diagrams at your kindergarten? Brent * *What makes you think you can teach? * *That I have taught and my students came back for more.* *I can handle dozens of clocks. I know what a spacetime diagram. It was taught in pre-school. Why did you introduce a red photon? A joke perhaps? How can a clock move at light speed? * *None of the clocks in the diagram are moving at light speed. The black one and the red one are moving at 0.5c as the label says. What is it you don't understand about this diagram? Brent * *One thing among several that I don't understand is how the LT is applied. For example, if we transform from one frame to another, say in E&M, IIUC we get what the fields will actually be measured by an observer in the target or primed frame. (I assume we're transferring from frame S to frame S'). But when we use it to establish time dilation say, we don't get what's actually measured in the target frame, but rather how it appears from the pov of the source or unprimed frame. Presumably, that's why you say that after a LT, the internal situation in each transformed frame remains unchanged (or something to that effect). AG* Can you give a concrete example? If you some coordinate-based facts in frame S (source frame) and use the Lorentz transformation to get to frame S' (target frame), the result should be exactly what is measured in the target frame S' using their own system of rulers and clocks at rest relative to themselves (with their own clocks synchronized by the Einstein synchronization convention). Jesse *Glad you asked that question. Yes, this is what I expect when we use the LT. We measure some observable in S, use the LT to calculate its value in S', and this what an observer in S' will measure. But notice this, say for length contraction. Whereas from the pov of S, a moving rod shrinks as calculated and viewed from S, the observer in S' doesn't measure the rod as shortened! This is why I claim that the LT sometimes just tells how things appear in the source frame S, but not what an observer in S' actually measures. AG* *Yes, although "appear" can be misleading when you consider things moving near light speed. More accurate is "measure", using the invariant speed of light.* *On another point concerning time dilation; I demonstrated that given two inertial frames with relative velocity v < c, it's easy to synchronize clocks in both frames provided we know the distance of clocks from the location of juxtaposition, but I was mistaken in concluding this alone shows time dilation doesn't exist. It does, because we insist on using the LT as the only transformation between these frames, and the reason we do this is because the LT is presumably the only transformation that guarantees the invariance of the velocity of light. So time dilation is, so to speak, the price we pay for imposing the invariance of the velocity of light on our frame transformation. But I remain unclear how a breakdown in simultaneity resolves the apparent paradox of two frames viewing a passing clock in another frame, as running slower than its own clock. AG* *Look at the diagram I provided. At the bottom (t=0) the three clocks are passing by one another. The blue clock sees the other two as running slower.* *Finally, for Brent, a word about "snarky". You get snarky when I don't understand something, like your "kindergarten" reference in one of your recent replies. And occasionally I am correct in my criticisms. Moreover, if you have typos in your explanation of your graph, you shouldn't be surprised if they make it hard to understand your graphical explanation of time dilation. AG* *So that one typo, which was correct elsewhere made it muddled for you?* *In part yes. When I think an author doesn't know what he's expounding about, I lose interest. Also, although I was a software engineer at JPL, I don't know LISP, so it would be hard to see what assumptions you made in generating the plot. And the plot is claimed to establish time dilation, and I'm not sure how you developed the width of the blue path say, to show time passes more rapidly compared to the other plots. AG* * Brent* -- 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/15945d64-1300-405d-8c2d-74e2d0dec83an%40googlegroups.com.
