On Sunday, January 26, 2020 at 1:57:51 AM UTC-6, Alan Grayson wrote: > > > > On Sunday, January 26, 2020 at 12:50:42 AM UTC-7, Lawrence Crowell wrote: >> >> On Sunday, January 26, 2020 at 1:20:53 AM UTC-6, Philip Thrift wrote: >>> >>> >>> >>> On Saturday, January 25, 2020 at 10:47:55 PM UTC-6, Brent wrote: >>>> >>>> >>>> >>>> On 1/25/2020 6:10 PM, Lawrence Crowell wrote: >>>> >>>> >>>> >>>> On Saturday, January 25, 2020 at 6:49:36 PM UTC-6, Brent wrote: >>>>> >>>>> >>>>> >>>>> On 1/25/2020 4:32 PM, Lawrence Crowell wrote: >>>>> >>>>> >>>>> >>>>> On Saturday, January 25, 2020 at 6:23:54 AM UTC-6, John Clark wrote: >>>>>> >>>>>> On Fri, Jan 24, 2020 at 5:21 PM Bruce Kellett <[email protected]> >>>>>> wrote: >>>>>> >>>>>> >> And I've heard a bunch of bad analogies but I still haven't heard >>>>>>>> a direct answer to my question: >>>>>>>> What is the difference between a "finite" universe that is >>>>>>>> expanding and accelerating forever and an infinite universe that is >>>>>>>> expanding and accelerating forever? >>>>>>>> >>>>>>> >>>>>> >>>>>> *> If you don't understand Brent's answer in terms of the range of >>>>>>> values in coordinate maps, then you will never understand the >>>>>>> difference.* >>>>>>> >>>>>> >>>>>> Then I guess I'll never understand the difference. >>>>>> >>>>>> >>>>>>> > A finite universe has a finite range of coordinate values. >>>>>>> >>>>>> >>>>>> NOPE! Brent specifically said "*I'm assuming a continuum spacetime. >>>>>> So even a 1cm interval takes an infinite number of labels*". Thus even >>>>>> if the universe is not expanding at all and even if it's only 1cm across >>>>>> a >>>>>> infinite number of labels with a infinite rage of coordinate values >>>>>> printed on them would be needed. >>>>>> >>>>> >>>>> Nope. Space and spacetime are an epiphenomenology. They are mental >>>>> perceptual models that result from large N-entanglements of quantum >>>>> states. >>>>> There are no infinite sets of points and labels, that would in fact be >>>>> uncountably infinite. These things only exist in our mathematical >>>>> representations or axiomatic systems. Now, what information we can get >>>>> about space from the IR domain of energy at extreme distances, such as >>>>> with >>>>> burstars etc,, is the representation of what we call space being smooth >>>>> fits the data. This does not mean that fundamentally there is an actual >>>>> smooth continuum of space. >>>>> >>>>> >>>>> I don't disagree, but you're getting further and further from saying >>>>> what it means for spacetime to be finite versus infinite. Since it's our >>>>> mathematical model, that should have a simple mathematical answer. >>>>> >>>>> Brent >>>>> >>>> >>>> There seems to be some sort of issue with the idea of continuum or >>>> space having an infinite number of points. I see this as a modern day >>>> version of asking how many angels can dance on a pin. >>>> >>>> >>>> I have no issue with it. But it doesn't mean that a spherical >>>> spacetime is infinite. The infinity of metric distance in a Riemannian >>>> space is not the same as the infinite cardinality of point in a real >>>> interval. >>>> >>>> Brent >>>> >>> >>> >>> >>> If the Universe is truly infinite, if you travel outwards from Earth, >>> eventually you will reach a place where there's a duplicate cubic meter of >>> space. The further you go, the more duplicates you'll find. >>> >>> Ooh, big deal, you think. One hydrogen pile looks the same as the next >>> to me. Except, you hydromattecist, you'll pass through places where the >>> configuration of particles will begin to appear familiar, and if you >>> proceed long enough you'll find larger and larger identical regions of >>> space, and eventually you'll find an identical you. And finding a copy of >>> yourself is just the start of the bananas crazy things you can do in an >>> infinite Universe. >>> >>> In fact, hopefully you'll absorb the powers of an immortal version of >>> you, because if you keep going you'll find an infinite number of yous. >>> You'll eventually find entire duplicate observable universes with more yous >>> also collecting other yous. And at least one of them is going to have a >>> beard. >>> >>> So, what's out there? Possibly an infinite number of duplicate >>> observable universes. We don't even need multiverses to find them. These >>> are duplicate universes inside of our own infinite universe. That's what >>> you can get when you can travel in one direction and never, ever stop. >>> >>> Whether the Universe is finite or infinite is an important question, and >>> either outcome is mindblenderingly fun. So far, astronomers have no idea >>> what the answer is, but they're working towards it and maybe someday >>> they'll be able to tell us. >>> >>> https://phys.org/news/2015-03-universe-finite-infinite.html >>> >>> @philipthrift >>> >> >> This is the case for a spatial surface that is infinite, but distance is >> using the idea of Poincare recurrence around 10^{10^{100}} light years >> away. This is far beyond the cosmological horizon and you could never get >> there no matter how long or extremely you try to accelerate outwards. With >> the spherical universe much the same also holds, but where getting around a >> spatial sphere with an enormous radius of curvature is impossible because >> it will always expand faster than you can travel. With the flat spacetime >> the existence of repeated versions of this local world means there is some >> covering space that is a torus or maybe the Poincare dodecahedral space. I >> tend to think this covering space is some form of quasi-crystal. For all we >> know we are in a cosmos with that sort of space. >> >> LC >> > > I don't see any basis for assuming infinite repetitions in an infinite > universe. It's sort-of like the claim that every thing that can happen, > must happen. What's your take? AG >
These repetitions are an aspect of what is called the level I multiverse. It is just the world beyond the horizon that if infinite is by statistical necessity going to reproduce local regions. LC -- 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/0f9098a7-3d64-4901-8eb3-00f8098237f8%40googlegroups.com.
