On Friday, December 30, 2022 at 10:13:41 AM UTC-6 [email protected] wrote: > Hence, the plausibility of the causality of Smolin's Autodidactic > Universe. > The Laws of the Universe Are Changing | RealClearScience > <https://www.realclearscience.com/2022/07/09/the_laws_of_the_universe_are_changing_841586.html> > > Slum-dunk? No, there is only more research to be funded to search for what > can be detected. > > For this peasant? A great working theory. > > >From what I know of observations and measurements there has been no recorded evidence of the laws of physics changing.
LC > > -----Original Message----- > From: Lawrence Crowell <[email protected]> > To: Everything List <[email protected]> > Sent: Fri, Dec 30, 2022 10:04 am > Subject: Re: Physics? Ok Astronomers view 2 distant Water Worlds so > following the physics I ask.. > > On Wednesday, December 28, 2022 at 11:41:36 PM UTC-6 Bruce wrote: > > On Thu, Dec 29, 2022 at 4:34 PM Brent Meeker <[email protected]> wrote: > > On 12/28/2022 9:01 PM, Bruce Kellett wrote: > > On Thu, Dec 29, 2022 at 3:29 PM Brent Meeker <[email protected]> wrote: > > Of course one reason there are "laws of physics" is what my late friend > Vic Stenger called Point Of View Invariance. This was his generalization > of Emmy Noether's theorem that showed every symmetry implied a conservation > law. > > > That is not strictly true. It is only continuous symmetries of the > Lagrangian that imply conservation laws -- not all symmetries. For example, > the symmetries of a square under rotation and reflection do not generate > any conservation laws. Neither do discrete symmetries like parity and > charge conjugation. > > So momentum is conserved because we want any law of physics to be > invariant under translation of a different location. Energy is conserved > because we want the laws of physics to be the same at different times, etc. > > > It is not what we want, it is what we find. We find that nature is > invariant under these continuous transformations, so we build those > symmetries into our laws. > > > Vic called in POVI because he wanted to extend it to transformations in > abstract spaces, e.g. gauge invariance. Of course the invariance depends > on the "point of view" in a sense. Things didn't look at all space > translation invariant to Aristotle. Galileo said ignore that your ship is > moving along the shore, just look at the dynamics in the cabin. So we > discovered these symmetries by learning what ignore as well as what to > measure. > > > The real point is that the laws are discovered, not imposed. The fact that > continuous symmetries correspond to conservation laws was discovered only > very much later. Most of the history of physics is about discovering what > works -- what the laws might be. POVI was thought of only very late in the > game, and is not a fundamental insight. > > Bruce > > > This begins to look a bit similar to the debate over whether mathematics > is objectively real or something invented. Emmy Noether gave consideration > to that boundary term we usually discard when deriving the Euler-Lagrange > formula to show that a symmetry was involved with this term. This symmetry > and that this boundary term is zero meant a conservation law. A law of > physics considered as such is something associated with covariant and > invariant properties of space, spacetime or an abstract space under some > set of transformations. Is this principle, a law of laws should we say, > something that is discovered or is some objective aspect of a mathematical > reality? > > The type D, II, III and N solutions, black holes = D and gravitational > waves = N, are vacuum solutions with the Weyl tensor C_{abcd} that wholly > determines the curvature. The Weyl curvature is an operator on Killing > vectors, such that Killing vectors are eigenvalued with the Weyl curvature > C_{abcd}K^bK^d = λK_aK_c. The type N solutions have Killing vectors that > have zero eigenvalue C_{abcd}K^d = 0. Type III spacetimes have λ = 0 and > type II and D have nontrivial eigenvalues that are unequal for C_{abcd} and > *C_{abcd}, for * the Hodge dual with C_{abcd}K^bK^d = λK_aK_c and > *C_{abcd}K^bK^d = λ’K_aK_c for λ ≠ λ’ and λλ ≠ 0. These Killing vectors > define symmetries and thus conservation laws. A timelike Killing vector > defines conservation of energy, a spacelike Killing vector defines > conservation of momentum, and a Killing bi-vector or one derived from such > defines conservation of angular momentum. That is a total of 1 + 3 + 6 = 10 > Killing vectors. These eigenvalued equations should make one think of the > Schrodinger equation. Indeed for a timelike Killing vector K_t = > √(g_{tt})∂_t so that this gives a general wave equation HΨ[g] = > iK_t∂Ψ[g]/∂t, which for g_{tt} = 1 is the Schrodinger equation. The ADM > approach to general relativity give NH = 0 and the Wheeler-deWitt equation > HΨ[g] = 0. General relativity does not automatically define conservation > laws. Conservation laws only occur with certain symmetries of spacetime. > This often occurs where there is an ADM mass defined by an asymptotic > condition of flatness or some other spacetime with constant curvature at a > distance. > > Conservation laws appear as asymptotic or boundary terms. The AdS/CFT > correspondence of Maldacena shows that a nonlocal quantum gravity theory > corresponds to a local conformal field theory on the conformal boundary of > the anti-de Sitter spacetime. The anti-de Sitter (AdS) spacetime has > constant negative curvature. This is a negative vacuum energy, where this > has some correspondence with string theory, such as the type I string > theory has a negative energy vacuum and its first excited state is a > negative energy state. The AdS_4 has a correspondence with black hole > physics. The AdS spacetime is not the spacetime of the observable universe. > It is though in line with the theory of Emmy Noether, also work by > Hurzebruch, and even the old Gauss-Bonnet theory. > > Physical spacetime is more similar to de Sitter spacetime, and is the > Friedmann-Lemaitre-Robertson-Walker spacetime with positive energy. This > means curvature is positive, which involves how space is embedded in > spacetime, and this does not have conservation laws. If that space is a > sphere S^3 the constant vacuum energy on this space grows with the > evolution of this space and volume growth. This is one reason that people > tend to prefer the flat space model, where vacuum energy is net "infinity" > and remains so. However, there is nothing to prevent vacuum energy density > from changing. The phantom energy model leading to a big rip of the cosmos > is possible, and the curious discrepancy between CMB and SNII data, with > the Hubble constant H = 70km/sec-Mpc and H = 74km/sec-Mpc respectively, > appears to resist analysis meant to show it is zero. If the phantom energy > model should be realized then conservation of energy, even with an infinite > flat space, is gone. > > The expansion of the universe also means we will not be able to observe > much physics that could be called “pre-cosmic,” or the quantum gravitation > of the pre-inflationary universe. Because of inflation and this 60-efolds > of expansion, expansion by ~ 10^{29}, a Planck scale region was expanded > from 10^{-33}cm to 10^{-4} cm. Since inflation began at 10^{30} sec in the > early universe, any Planck scale fluctuation involved with the generation > of the universe would have been 10^{-23}cm, and was expanded to 10^6 cm --- > beyond the scale of the then observable universe ~ 10cm. After inflation > the observable universe with a scale of ~ 10cm an possible Planck scale > process was stretched by more normal expansion to 10^{10} light years, and > might appear as some order anisotropy in the CMB. Using blackbody physics, > these quanta would have been a tiny aspect of the early universe. These > would be very difficult to find in the CMB. Beyond that, we cannot observe > anything. Any pre-cosmic physics emerged from something smaller than the > Planck scale and is expanded beyond any measurable scale on the CMB. > > John Wheeler said that the ultimate law of physics is there is no law. We > may then have something similar to this, where what we call the laws of > physics are just local emergent pattern in the observable universe. At > large the universe may simply have no conservation laws and ultimate there > are globally no physical laws. > 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/e45935c8-1aa6-44a6-94a4-09e43c6a2bd0n%40googlegroups.com > > <https://groups.google.com/d/msgid/everything-list/e45935c8-1aa6-44a6-94a4-09e43c6a2bd0n%40googlegroups.com?utm_medium=email&utm_source=footer> > > . > -- 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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