On Wednesday, January 22, 2020 at 9:03:55 PM UTC-7, Alan Grayson wrote: > > > > On Wednesday, January 22, 2020 at 8:54:37 PM UTC-7, Brent wrote: >> >> >> >> On 1/22/2020 6:38 PM, Alan Grayson wrote: >> >> >> >> On Wednesday, January 22, 2020 at 1:34:00 PM UTC-7, Lawrence Crowell >> wrote: >>> >>> On Wednesday, January 22, 2020 at 11:33:04 AM UTC-6, John Clark wrote: >>>> >>>> On Wed, Jan 22, 2020 at 12:06 PM Lawrence Crowell < >>>> [email protected]> wrote: >>>> >>>> > *It is then possible to have an expanding accelerated cosmos that is >>>>> spherically closed.* >>>> >>>> >>>> So if I keep going I will eventually return to where I started even >>>> though everything is constantly getting more distant from me and is doing >>>> so at an accelerating rate? >>>> >>>> John K Clark >>>> >>> >>> For an accelerated expansion of the sphere there is a cosmological >>> horizon that one can't cross. in other words, the sphere will keep >>> expanding faster than you can ever go. Think of the scene in the movie >>> "*The >>> Shining*" with Jack Nicholson where the hotel hallway telescoped away >>> faster than he could run. >>> >>> LC >>> >> >> I don't think it depends on acceleration. As long as the universe >> expands, even at a constant rate, at some distance, the distance between, >> say, an Earth observer, and some terminal point along a line of sight, will >> exceed 300,000 km (the distance light travels in one second) and points >> beyond that will keep increasing the increment every second, creating a >> cosmological horizon that light cannot cross. >> >> >> That's not quite right. Light can cross it just fine. But a photon >> crossing it toward us, can never reach us. This is how the Hubble boundary >> differs from a black hole event horizon. >> >> Brent >> > > Good point. TY. AG >
Now I'm not so sure. ISTM, the photons that never reach us, never cross the event horizon. They're emitted in a region receding faster than the SoL, so they can never cross it. AG > >> This is because the creation of the horizon is purely a geometric effect >> of the expansion, and the rate of expansion is irrelevant. 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/928bfcb1-8892-4858-a5d3-c2e6297c0256%40googlegroups.com >> >> <https://groups.google.com/d/msgid/everything-list/928bfcb1-8892-4858-a5d3-c2e6297c0256%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >> >> -- 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/a4c40e48-604c-4ed4-bfa9-98206aef8c92%40googlegroups.com.
