On Friday, June 20, 2025 at 5:50:45 AM UTC-6 Alan Grayson wrote:
On Friday, June 20, 2025 at 5:41:19 AM UTC-6 John Clark wrote: On Fri, Jun 20, 2025 at 3:44 AM Alan Grayson <[email protected]> wrote: > *if a test particle is released from a state of spatial rest (due to an external force ceasing to be applied); why does it start of move in a theory where no forces exist? * *I think you're trapped in an infinite loop. If you keep asking the exact same question then you will keep getting the exact same answer. So I suggest you reread what the previous answers were.* *John K Clark See what's on my new list at Extropol <https://groups.google.com/g/extropolis>* I'll do that, but as I recall you posted a weak argument which depended on the equivalence of gravitational and inertial mass, so the consequences immediately followed, AG Here, in part, is what you wrote earlier to answer to my question; what causes a test particle it to begin spatial motion when initially being spatially at rest, after a restraining force is removed: *> I fail to see how the EP implies geodesic motion. If true, the proof must be exceedingly subtle.* *I'll try one more time. If you are in freefall then you experience no gravity, so from your perspective your local spacetime is flat and things move in a path that is the shortest distance between two points, a Euclidean straight line. But from my perspective standing on the Earth's surface you are being affected by gravity and are moving through spacetime that is curved and non-Euclidean. The Equivalence Principle says both points of view are equally valid, but the only way that could be true is if I see you moving in a path that is the shortest distance between two points in 4D non-Euclidean space, and that is a geodesic.* *> If we assume mass/energy somehow causes a distortion in spacetime gemetry, and we hold a test mass spatially at rest in a gravity field, the question "why does it move"* *If you are holding an object and standing motionless on the Earth's surface then you and the object are still following a path through 4D non-Euclidean spacetime because both of you are still moving through time, but that path is NOT a geodesic because a force is being applied to the bottom of your feet. When you release the object its spacetime path suddenly changes to that of a geodesic while your path remains non-geodesic. And things on different spacetime paths is the definition of "movement".* ********************* I don't understand how your text answers my question. I highlighted your claim above. What causes the "sudden" change you refer to above. Are you invoking magic? You seem to claim that 4D curvature is the cause, as if it replaces an external force called gravity. Maybe you don't understand my question or won't admit you don't know the answer. 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/88778151-6faa-412e-ad7a-7cea2bc780a9n%40googlegroups.com.
