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 * 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/CAFxXSLTBtfzo%3D7bJ9C32yXXXHcJs3xeiVkMSasRRc0hT5hAtww%40mail.gmail.com.
