On Fri, Jan 17, 2025 at 7:22 PM Alan Grayson <agrayson2...@gmail.com> wrote:
*> If you model any observer leaving Earth, that observer cannot be > inertial. AG * *You can if that observer had always been inertial and had passed the vicinity of earth at a given "proper time", the time he sees on his wristwatch. And if X and Y are moving relative to each other they will each observe that the other's wristwatch is running slower than their own. If your trajectory is inertial (meaning you're not being pushed around by external forces) , you will always take the path that maximizes your proper time between two events. At first that may seem like a paradox but if you dig a little deeper you realize that it is not, it's just odd. You really should look at that video I recommended. * *Richard Feynman gave a related anecdote in his book "Surely you're joking Mr. Feynman" when he posed this puzzle to an assistant of Einstein: * *"You blast off in a rocket which has a clock on board, and there's a clock on the ground. The idea is that you have to be back when the clock on the ground says one hour has passed. Now you want it so that **when you come back, your clock is as far ahead as possible. According to Einstein, if you go very high, your clock will go faster, because the higher something is in a gravitational field, the faster its clock goes. But if you try to go too high, since you've only got an hour, you have to go so fast to get there that the speed slows your clock down. So you can't go too high. The question is, exactly what program of speed and height should you make so that you get the maximum time on your clock?"* *"This assistant of Einstein worked on it for quite a bit before he realized that the answer is the real motion of matter. If you shoot something up in a normal way, so that the time it takes the shell to go up and come down is an hour, that's the correct motion. It's the fundamental principle of Einstein's gravity--that is, what's called the "proper time" is at a maximum for the actual curve."* *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* um8 > > -- 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/CAJPayv15kbpoSDNt8bjSqVQqj46keoA3_xBYHuxLFWm%3DiznZrA%40mail.gmail.com.
