Le mar. 14 janv. 2020 à 12:47, Alan Grayson <[email protected]> a écrit :
> > > On Tuesday, January 14, 2020 at 4:04:27 AM UTC-7, Bruce wrote: >> >> On Tue, Jan 14, 2020 at 9:30 PM Alan Grayson <[email protected]> wrote: >> >>> On Tuesday, January 14, 2020 at 3:06:48 AM UTC-7, John Clark wrote: >>>> >>>> On Mon, Jan 13, 2020 at 9:03 PM Alan Grayson <[email protected]> >>>> wrote: >>>> >>>> >> If infinite distances makes you squeamish I don't see how you can >>>>>> consistently embrace infinite outcomes. And besides this is not >>>>>> mathematics, in physics nothing is provably infinite, nobody has >>>>>> ever found an infinite number of anything. >>>>>> >>>>> >>>>> *> It's not a matter of, or a case of being squeamish with infinite >>>>> outcomes. I just don't see how cosmologists can claim the universe is flat >>>>> -- which means infinite in spatial extent -- if it starts small and >>>>> expands >>>>> for a finite time.* >>>>> >>>> >>>> Infinity is not a number, infinity is a process that evolves in time. >>>> If a cosmologists says the universe is infinite he means that a pulse of >>>> light will keep getting more distant from its starting point and never >>>> return. >>>> >>> >>> *That's what I mean! Only it's not true if the universe is spherical.* >>> >> >> It is true for a de Sitter universe as a solution of the Einstein >> equations. If the universe is spherical, it will eventually recontract, and >> light cannot get right round and back to its starting point before the >> universe recontracts to a point. If the universe is expanding via dark >> energy, even if spherical, light still cannot get round because of the >> expansion. In other words, you can never see the back of your own head no >> matter what the geometry of the universe!!!!! >> >> Bruce >> >>> > *Since it's not a perfect sphere, light never exactly returns to its > starting point. That's just an approximation for discussion purposes. So > let it contract. The point is that if the universe starts off small and > expands at any finite rate for a finite time (aka, the age of the > universe), it can't be flat, which implies spatially infinite. Sure it's > nearly flat, but not exactly flat, like a huge sphere. I don't know why > this is so hard to see. AG* > The only thing expansion tells us is that our observable part of the universe started small... nothing tells us that it was all there is... the universe could have been infinite, and our observable part is an infinitesimal portion of it... as of singularity, yes that means our theories break down, but I seen nothing bad in infinity or even infinitely dense... all in all, that's the magical part of reality... at one point, something miraculous happened. That something is reality. In the end, I can't see more than let there be light at the bottom, it's as nonsensical as anything else for that. There is no reason, no logic for us to be here. It just is. > > >> * Let's forget it. These discussions are worthless. 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/50d19fdf-2c5c-44aa-8fda-f3121ee7c9c8%40googlegroups.com > <https://groups.google.com/d/msgid/everything-list/50d19fdf-2c5c-44aa-8fda-f3121ee7c9c8%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/CAMW2kAo-%3DftwWpzJsbS6Bhd6RfpxGS204mq0n0TZ2MAtUcydWw%40mail.gmail.com.
