Missing Bruno here, but in the UDA framework, reality is continuous, emerging from the infinite computations that pass through your current state.
Quentin Le mar. 18 févr. 2025, 23:42, Brent Meeker <[email protected]> a écrit : > > > On 2/17/2025 5:08 PM, Alan Grayson wrote: > > > > On Monday, February 17, 2025 at 12:49:27 PM UTC-7 Liz R wrote: > > Apparently the simplest model of the universe is one that is infinite at > all times (according to Max Tegmark) - the "concordance" model? There is no > reason an infinite universe couldn't have undergone scale expansion, an (in > this case, presumably uncountably) infinite thing remains infinite no > matter how much you expand it. Whether the universe is a continuum is key > to this, so it depends on an as-yet unknown TOE. If spacetime is quantised > - in some sense - then whether it could be infinite, and whether it could > expand, might still be up for grabs. > > Note that a quantised spacetime would presumably only contain a finite > number of possible states inside any volume (e.g. our cosmological horizon) > and hemce an infinite universe would eventually repeat itself across > sufficiently large distances. Again quoting Max Tegmark, this would occur > for our Hubble sphere at something like a distance of 10^10^37 metres (from > memory - the actual figures don't really matter much for any practical > purpose, just note that they make a googol look ultramicroscopic). Assuming > that repeated identical quantum states are indistinguishable, an infinite > quantised universe would in fact be "piecewise finite" on Vast scales - > repeating arbitrarily large identical volumes would be not just > indistinguishable in principle but actually identical. So on this basis, > the universe would be a sort of Library of Babel in which all possible > quantum states exist (including "Harry Potter" and "White Rabbit" > universes) - but since the number of possible states is finite for a given > volume, it would eventually run out of combinations and repeat itself. > Quite what this would look like on "hyperastronomical scales" I leave to > the mathematicians. > > > > *FWIW, our best current measurements fail to show any quantization of > spacetime. This was discussed here by Lawrence Crowell a long time ago, and > I don't recall the level of fineness of these results. AG * > > > > > > *It was a paper I cited years ago that noted there was no dispersion of > gamma rays from very distant galaxies which ruled out on discrete structure > to space down to less than the Planck scale. Here's a more recent paper: > https://physics.aps.org/articles/v17/s99 > <https://physics.aps.org/articles/v17/s99> Brent * > > > > By the way the Cosmological Principle is an observation / assumption, not > an actual principle based on any physical laws. > > > *Not exactly. Physical observation do play a significant role in > generating principles. Faraday's observations of the behavior of magnetic > fields comes to mind, and the MM experiment, which Einstein was aware of, > which showed the velocity of light is independent of an observer's motion. > In the case of the CC, we have ambiguous results. The CMBR suggests the > universe was very close to homogeneous and isoptropic when its age was > about 380,000 years old, but measurements much later in time show it's > actually lumpy, with ultra long filaments containing galaxies, separated by > huge voids. I'd go with the later, showing that the CC is false. AG * > > > > On Monday, 17 February 2025 at 18:05:20 UTC+13 Alan Grayson wrote: > > On Sunday, February 16, 2025 at 1:57:39 AM UTC-7 Quentin Anciaux wrote: > > AG, your argument assumes a false dichotomy between "nothing" and > "something" > > > Why a false dichotomy? No transition from finite to infinite if it was > alway infinite, but was it? AG > > while making unjustified claims about infinity. If the universe is > infinite now, it was infinite at the Big Bang, there’s no "transition" from > finite to infinite. Your assertion that this is "not remotely intelligible" > is just an appeal to personal incredulity, not an actual argument. > > Quentin > > Le dim. 16 févr. 2025, 09:44, Alan Grayson <[email protected]> a écrit : > > > > On Saturday, February 15, 2025 at 9:20:55 PM UTC-7 Alan Grayson wrote: > > On Saturday, February 15, 2025 at 9:11:22 PM UTC-7 Brent Meeker wrote: > > On 2/15/2025 7:03 PM, Alan Grayson wrote: > > On Saturday, February 15, 2025 at 1:56:14 PM UTC-7 Brent Meeker wrote: > > On 2/14/2025 11:36 PM, Alan Grayson wrote: > > > > On Friday, February 14, 2025 at 11:06:42 PM UTC-7 Brent Meeker wrote: > > > > On 2/14/2025 3:23 PM, Alan Grayson wrote: > > > > On Wednesday, February 12, 2025 at 12:36:38 PM UTC-7 Brent Meeker wrote: > > > > On 2/12/2025 12:55 AM, Alan Grayson wrote: > > If the age of the universe is finite, which is generally believed, then no > matter how fast it expands, it can never become spatially infinite, So,* > IF* it is spatially infinite, this must have been its initial condition > at or around he time of the Big Bang (BB). But this contradicts the > assumption that it was at a super high temperature at or around the time of > the BB. > > No it doesn't. I can be infinite and high temperature. What gave you > idea it couldn't? > > IOW, if we run the clock backward, the universe seems to get incredibly > small, > > If the universe is infinite, then it is only the Observable Universe that > gets incredibly small. > > > > *Is there any principle you are aware of, which prevents an infinite > universe from becoming incredible small? * > > > > *It would have to undergo an infinite change in size in a finite time, > which would require infinite relative velocities. Brent* > > > *I can't imagine a universe starting as infinite in spatial extent -- can > you? -- * > > As well as I can imagine any infinite thing. Imagination can be trained. > My supervising professor, Englebert Schucking, could visualize four > dimensional objects and draw their projection on the blackboard. If you > can't do that, you just have to suppress some dimensions; then in the (t,r) > plane there's an infinite line, the t-axis, and to the right of this line > is the (t,r) plane and in that plane everything is moving apart. Just look > at Ned Wright's cosmology tutorial: > > https://www.astro.ucla.edu/~wright/cosmolog.htm > > Brent > > > The problem is this; how does one imagine a universe which suddenly comes > into being, initially resumably with zero spatial extent, and when it does, > it's infinite in spatial extent? IMO, this would be a singularity implying > infinite spatial expansion instantaneously. I have no alternative but to > reject this model for a finite one, starting small and hot, and expanding, > since I have no idea what it means to begin infinitely. I am open to > suggestions. AG > > Expand your imagination. Remember "infinite" just means without bound. > You don't have to imagine the whole infinite line, just imagine a line > without imagining it's ends. > > > Not saying I believe it, but the best bet at this point in time, is that > the universe began as a quantum fluctuation, thus small, very small! AG > > BTW, since a finite volume such as the observable universe, can originate > from a point, those pictorial models of the evolution of the universe, > starting from a point, aka the BB, are apparently accurate in their > descriptions. That is, they're not necessarily simplifications of the > evolution. AG > > Probably they are since they don't take account of quantum mechanics; but > we don't know exactly how they are wrong. > > Brent > > > Consider this: For Nothing to become Something and also be infinite in > spatial extent, that Something must have that infinity as its initial > condition, given that it now has a finite age. But transforming from > Nothing to Something and having that infinity as its initial condition as > infinite in spatial extent, is, if you think about, not remotely > intelligible. For this reason, I conclude it can't have this infinity as > its initial condition and can't be flat, which implies this infinity. 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