On Wednesday, February 20, 2019 at 7:09:10 AM UTC-7, John Clark wrote: > > > >* Newton "explained" * > > > Why did you put explained in quotation marks? If you can predict what > something is going to do then you've explained it, the better the > prediction the better the explanation. I don't know what else the word > could possibly mean. And in science no explanation is perfect, but some are > less wrong than others. >
*QM better illustrates the justification for quotes. Many interpretations that make the same predictions. AG * > > *> why a body at "rest" can start moving, via the application of "force"* > > > And Einstein explained that a body moving in a geodesic through 4D > spacetime will take a path that is not a geodesic if a force is applied. > The Earth is moving in a straight line (aka a geodesic) through curved > spacetime; the reason Earth's orbit looks elliptical to us is due to map > distortion, the same reason that in a flat map of the curved surface of the > Earth Greenland looks larger than South America and is almost as large as > Africa. > Except that it's even worse, in one we're projecting the 2 D curved surface > of the Earth into the flat 2D surface of the map, but with Einstein we're > projecting a curved 4D volume into a flat 3D volume. > > *> What does "rest" mean in GR * > > > In General Relativity moving in a geodesic is as close as you can get to > the traditional idea of rest, but as long as time passes you're going to be > moving through 4D spacetime. > *If you're at spatial rest in spacetime in the presence of a gravitational source, how does GR explain the subsequent spatial motion? AG * > > *> what causes "motion" from that pov?* > > > Force, same as with Newton. > > 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.
