On Mon, Dec 11, 2017 at 12:15:58PM -0800, [email protected] wrote: > > *IIUC, you're saying that tensors transform covariantly, that is, > independent of coordinate system, but you haven't addressed my question why > Einstein would think accelerating frames are equivalent, or why a theory of > gravity could be, or must be covariant. BTW, is it correct to say that > "covariance" is a synonym for "Lorentz invariant"? TIA, AG*
All physical theories must be covariant. It is nonsense for physical law to depend on one's chosen coordinate system. Lorentz invariance is just one form of covariance. As for the principle of equivalence, that is something else, unrelated to covariance. Empirically they have been found to be identical, plus it is required in Newtonian mechanics in order to have stable orbits. Even now, there are still experiments directly testing the principle of equivalence. A finding of a departure from it would be very big news! -- ---------------------------------------------------------------------------- Dr Russell Standish Phone 0425 253119 (mobile) Principal, High Performance Coders Visiting Senior Research Fellow [email protected] Economics, Kingston University http://www.hpcoders.com.au ---------------------------------------------------------------------------- -- 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.
