On Tuesday, December 19, 2017 at 8:51:51 PM UTC, Brent wrote: > > > > On 12/18/2017 11:44 PM, [email protected] <javascript:> wrote: > > Invariants are always the important things in physics because they are >> what we can have intersubjective agreement on. >> >> Brent >> > > *IIUC, the field equations are covariant, which means coordinate system > independent. * > > > Right. Covariant means that something that changes in such a way that > invariant things remain the same. So vectors components transform > covariantly so that they keep the vector physically the same. > > *Isn't Newton's Law of Gravitation also coordinate independent? That is, > if we use Newton to calculate the planetary orbits, won't we get the same > results in different coordinate systems? * > > Right. >
*If Newton's Law of Gravitation is covariant -- that is, coordinate frame independent -- I'd expect it to to be invariant between inertial frames, but I don't believe it is. That is, I don't think a LT between inertial frames will leave the form of the law unchanged. How do you resolve this problem? TIA, AG* > > *... Is there a distinction in GR between frame independence and > coordinate independence? AG* > > > I'd say frame independence is a special case of coordinate independence. > It refers only to relative motion of coordinate frames. > > Brent > > -- 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.
