Le lun. 13 janv. 2020 à 11:10, Alan Grayson <[email protected]> a écrit :
> > > On Monday, January 13, 2020 at 2:54:48 AM UTC-7, Quentin Anciaux wrote: >> >> >> >> Le lun. 13 janv. 2020 à 10:50, Alan Grayson <[email protected]> a >> écrit : >> >>> >>> >>> On Monday, January 13, 2020 at 2:38:57 AM UTC-7, Quentin Anciaux wrote: >>>> >>>> >>>> >>>> Le lun. 13 janv. 2020 à 10:28, Alan Grayson <[email protected]> a >>>> écrit : >>>> >>>>> >>>>> >>>>> On Monday, January 13, 2020 at 1:33:01 AM UTC-7, stathisp wrote: >>>>>> >>>>>> >>>>>> >>>>>> On Mon, 13 Jan 2020 at 13:48, Alan Grayson <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> >>>>>>> On Sunday, January 12, 2020 at 8:58:06 AM UTC-7, John Clark wrote: >>>>>>>> >>>>>>>> On Thu, Jan 2, 2020 at 2:30 AM Alan Grayson <[email protected]> >>>>>>>> wrote: >>>>>>>> >>>>>>>> >>>>>>>>> *> If we're convinced it's finite in age, then it can't be >>>>>>>>> infinite in spatial extent. AG * >>>>>>>> >>>>>>>> >>>>>>>> We don't know for sure our universe is infinite in size and we'll >>>>>>>> never know for sure because we'll never be able to measure precisely >>>>>>>> zero >>>>>>>> curvature with no error at all, but we do know it's pretty damn flat, >>>>>>>> if >>>>>>>> it's curved it's so slight that a light beam would have to go at least >>>>>>>> 500 >>>>>>>> times as far as our telescopes can see for it to return where it >>>>>>>> started. >>>>>>>> So if you respect the empirical evidence for the Big Bang but the idea >>>>>>>> of a >>>>>>>> beginning of a infinitely sized universe makes you unhappy then the >>>>>>>> Multiverse idea offers you an obvious solution, you get an infinitely >>>>>>>> large >>>>>>>> infinitely old Multiverse but with the observable universe having a >>>>>>>> beginning and being only finitely large. However I understand the >>>>>>>> Multiverse makes you unhappy too. I fear you may be destined to be >>>>>>>> unhappy. >>>>>>>> >>>>>>>> By the way ... does the inverse also make you unhappy, something >>>>>>>> infinitely old but finite in spatial extent? >>>>>>>> >>>>>>>> John K Clark >>>>>>>> >>>>>>> >>>>>>> *All the models pictorially represented, have the Universe beginning >>>>>>> very small, and inflation is claimed to increase its size from, say, >>>>>>> much >>>>>>> smaller than a proton, to about the size of the Earth or Solar System >>>>>>> in a >>>>>>> few Planck intervals. If it begins small, or if you run the clock >>>>>>> backward >>>>>>> it becomes progressively smaller, how could it have started with >>>>>>> infinite >>>>>>> spatial extent? Don't you see something wrong with the model? AG* >>>>>>> >>>>>> >>>>>> The model says that a subset of the universe starts small and gets >>>>>> bigger. This is not inconsistent with the whole universe starting and >>>>>> remaining infinite in spatial extent. >>>>>> >>>>>>> -- >>>>>> Stathis Papaioannou >>>>>> >>>>> >>>>> *I thought I made that clear; what I am calling "the universe" is >>>>> precisely the SUBSET you refer to, which starts small and gets bigger. It >>>>> is THAT SUBSET which cosmologists claim has infinite spatial extent, based >>>>> on measurements. What you're calling "the whole universe" includes the >>>>> underlying entity on which the BB started, and on which measurements >>>>> CANNOT >>>>> be made. It could be infinite in spatial extent, or is possibly an entity >>>>> for which the concept of spatial extent might not exist. AG* >>>>> >>>> >> And so what do you see not contradictory in the existence of the universe >> itself ? Either it has always been, or not, and if not, that makes no >> sense. I see nothing contradictory to have something infinite, so it could >> always has been infinite in content, seeing it as zero volume is a mistake >> because that presuppose a volume in another space. What I'm saying is that >> there was infinite content (and still is) but all metrics (space) was of >> zero extends, and inflation extended the "space" not the content. >> > > *I don't think you understand the issue I've raised; namely, if our bubble > has a finite age and is expanding, it must be finite in spatial extent > since the expansion rate is finite. But a flat universe, claimed by most, > maybe all cosmologists, is infinite in spatial extent. How could it start > infinite in spatial extent, yet be tiny in the beginning? I conclude that > our universe, that is, our bubble (which doesn't include the substratum > from which it arose), must be spherical and closed. AG* > If the content was infinite, but space metric inflated from zero to something, the result is still infinite and space arise, as there was an infinity of space whose metric got bigger, there is still infinity after inflation, just more empty space in between matter. > >> Anyway, in the end, there can't be an explanation which make sense. The >> fact we're here in the first place being able to ask question is magical. >> >> Quentin >> >>> >>>> As the bigbang is a singularity at the start... what prevents it to >>>> contain an infinite content in a zero/small volume, after all it's a >>>> singularity and we know only things after the big bang started ? and after >>>> inflation (which I understand is only space metric which inflate), there is >>>> still an infinite content. >>>> >>> >>> *The BB is only a singularity as far as GR is concerned, because GR >>> fails at that point in time. When we have a better theory, the alleged >>> singularity at T = 0 will go away. What you call "infinite content in zero/ >>> small volume" makes no sense, which is why we call this condition is called >>> a singularity! How could the content be space, if you've have zero or small >>> volume. This idea is immediately, and obviously, self contradictory. 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/c9a07678-7721-4d68-ba7a-ea0b3455c4d7%40googlegroups.com >>>>> <https://groups.google.com/d/msgid/everything-list/c9a07678-7721-4d68-ba7a-ea0b3455c4d7%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>> . >>>>> >>>> >>>> >>>> -- >>>> All those moments will be lost in time, like tears in rain. (Roy >>>> Batty/Rutger Hauer) >>>> >>> -- >>> 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/a31f806e-0b3c-4bc3-a6d9-5b1543f11918%40googlegroups.com >>> <https://groups.google.com/d/msgid/everything-list/a31f806e-0b3c-4bc3-a6d9-5b1543f11918%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> >> >> -- >> All those moments will be lost in time, like tears in rain. (Roy >> Batty/Rutger Hauer) >> > -- > 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/692e04e2-eec2-4c8d-aca7-011087e41608%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/692e04e2-eec2-4c8d-aca7-011087e41608%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- All those moments will be lost in time, like tears in rain. (Roy Batty/Rutger Hauer) -- 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]. 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