On Sunday, January 19, 2020 at 4:46:41 PM UTC-7, Brent wrote: > > > > On 1/19/2020 2:44 PM, Alan Grayson wrote: > > > > On Sunday, January 19, 2020 at 11:52:18 AM UTC-7, Brent wrote: >> >> >> >> On 1/18/2020 11:58 PM, Alan Grayson wrote: >> >> >> >> On Sunday, January 19, 2020 at 12:18:54 AM UTC-7, Brent wrote: >>> >>> >>> >>> On 1/18/2020 10:56 PM, Alan Grayson wrote: >>> >>> I don't claim anything except that GR has solutions for a cosmos in >>>> which space is flat and, in that solution, space is infinite and >>>> empirically it appears that space is flat. >>>> >>> >>> *Measurements don't establish it's flat, as I previously argued. And, as >>> you previously stated, the sign of k, the parameter in GR intimately >>> associated with curvature, is folded into the initial conditions. But since >>> the initial conditions are really unknown, or are speculative, you can >>> assume initial conditions which satisfy your bias, in this case FLAT. AG * >>> >>> >>> No. It's not an assumption. Empirically the universe appears flat, >>> which (assuming the FLRW model) implies it was always flat. It is not a >>> question of assuming an initial condition, it is inferring the initial >>> condition from present measurements of k. >>> >> >> *This seems to modify what you wrote a few day ago. In any event, >> "empirically" means "measurement", and one cannot measure the curvature as >> exactly zero, which is what you need to empirically establish flatness. The >> measurements are very close to zero, but not zero. AG* >> >> >> When you measure something and it is so close to zero as to be >> indistinguishable from zero, then taking it to be zero is not an assumption. >> >> Brent >> > > *But it could be HUGELY spherical and seem to be zero! * > > > That's right it COULD! But that's not the way to bet and just because it > could wrong doesn't make it an assumption. The whole theory of general > relativity not only could be wrong, we in fact know it must be wrong at > sufficiently short distances. > > > *The cases could be indistinguishable. What I want to know is this; when > you solve using the FLRW model, does it give exactly zero for the > curvature? TIA, AG * > > > Solutions exist for all different curvatures. >
*OK, but what value of curvature does the FLRW model give? AG * > > 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 view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/ccb8b95e-60b3-4d7a-82b4-b58bb7983ee4%40googlegroups.com.
