On Tuesday, March 26, 2019 at 6:28:18 AM UTC-6, John Clark wrote: > > On Tue, Mar 26, 2019 at 4:40 AM <[email protected] <javascript:>> wrote: > > >>>Einstein never said everything is relative. Unlike velocity there is >>>> such a thing as absolute acceleration, if that were not true the Twin >>>> Paradox could not be resolved. >>>> >>> >>> *>> But in GR don't the field equations take the same form in all >>> frames, including accelerating frames, which if I understand correctly, IS >>> the Principle of Relativity? TIA, AG* >>> >> >> *> Clark, how about an answer?* >> > > *Sir yes sir!* Saying the field equations are the same form in all > reference frames is just another way of saying the fundamental laws of > physics are the same everywhere, and if they weren't the same > everywhere General Relativity would be a very bad theory. It took Einstein > 10 years to find equations that fit these invariant requirements so that in > every reference frame the spacetime distance between 2 events is the same, > and in every reference frame absolute acceleration exists but absolute > motion does not, and every frame is accelerating except for one moving > through flat spacetime (aka a zero gravitational field) in a straight path, > and for every curved spacetime path there must be a force being applied > unless that particular spacetime curve happens to be a geodesic. > > John K Clark >
*TY! But what still puzzles me is that, according to Brent, there is no general transformation from one accelerating frame to another accelerating frame (only a local LT). So, although the field equations are claimed to be the same in all frames, accelerating or not, how does one prove that without applying a general (non existent!) transformation? TIA, 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
