On Thursday, July 23, 2020 at 8:27:52 AM UTC-6, Lawrence Crowell wrote: > > Coordinates are not the basis of physics. Curvatures are covariant, while > connections and coordinates are not. These can be imposed in many ways, > similar to a gauge choice. > > LC >
That right; coordinates are not the basis of physics. That's why Einstein had to cast his GR equation in tensor form, so the laws of physics would be independent of coordinate systems. But you're asserting, or so it seems, that there is a unique coordinate system wherein the external gravitational effect of a BH can be calculated. This is what I object to. AG > > > On Thursday, July 23, 2020 at 6:49:44 AM UTC-5 [email protected] wrote: > >> >> >> On Thursday, July 23, 2020 at 5:41:42 AM UTC-6, Lawrence Crowell wrote: >>> >>> On Thursday, July 23, 2020 at 5:56:32 AM UTC-5 [email protected] >>> wrote: >>> >>>> >>>> >>>> On Saturday, July 18, 2020 at 6:31:23 AM UTC-6, Alan Grayson wrote: >>>>> >>>>> >>>>> >>>>> On Saturday, July 18, 2020 at 6:18:28 AM UTC-6, Lawrence Crowell wrote: >>>>>> >>>>>> The tortoise coordinates is found from the Schwarzschild metric >>>>>> >>>>>> ds^2 = (1 - 2m/r)dt^2 - (1 - 2m/r)^{-1}dr^2 - r^2dΩ^2 >>>>>> >>>>>> where for a signal leaving a point near the black hole with ds = 0 >>>>>> (null path) and propagating radially out, dΩ = 0, we have dt = dr/(1 - >>>>>> 2m/r) which then leads to >>>>>> >>>>>> T = t - t0 - 2m ln|r - 2m|. >>>>>> >>>>>> That is the tortoise coordinate. Please look this up to read further. >>>>>> I can't spend beaucoup time going over this for weeks to come. >>>>>> >>>>>> LC >>>>>> >>>>> >>>>> You don't have to. We're done. But you should IMO address Brent's >>>>> objection, maybe on another thread. AG >>>>> >>>> >>>> When it comes to GR, you're a genius; no question about it. I wouldn't >>>> want to waste your valuable time. But consider this; the Schwartzschild >>>> metric applies to NON-ROTATING masses. Do you really think a massive >>>> contracting star which forms a BH will be non-rotating? Obviously, it will >>>> be RAPIDLY rotating, like an ice skater who contracts her arms. Brent also >>>> had some substantive questions about your model. But I see you prefer your >>>> illusions than to address his objections. AG >>>> >>> >>> The result is similar, but more complex. The same calculation can be >>> done for the Kerr solution. It is just a lot more complicated >>> mathematically. >>> >>> LC >>> >> >> If you say so. In any event, the idea that an objectively existing >> gravitational field outside a BH should depend on the choice of a >> particular coordinate system, seems a non-starter. 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/7657a0e7-e53f-4c0d-989a-54ada2e24bbao%40googlegroups.com.
