On Tue, Mar 26, 2019 at 4:40 AM <[email protected]> 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 -- 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.
