On Sunday, December 31, 2017 at 7:25:53 AM UTC-7, Lawrence Crowell wrote: > > On Saturday, December 30, 2017 at 8:33:17 PM UTC-6, [email protected] > wrote: >> >> >> >> On Saturday, December 30, 2017 at 2:40:22 PM UTC-7, Lawrence Crowell >> wrote: >>> >>> On Saturday, December 30, 2017 at 2:28:52 PM UTC-6, [email protected] >>> wrote: >>>> >>>> >>>> >>>> On Saturday, December 30, 2017 at 1:03:58 PM UTC-7, Lawrence Crowell >>>> wrote: >>>>> >>>>> On Friday, December 29, 2017 at 8:45:41 PM UTC-6, [email protected] >>>>> wrote: >>>>>> >>>>>> >>>>>> >>>>>> On Friday, December 29, 2017 at 6:59:22 AM UTC-7, Lawrence Crowell >>>>>> wrote: >>>>>>> >>>>>>> The cosmological constant is Λ ~ 10^{-52}cm^{-2} and the scale >>>>>>> factor evolves as >>>>>>> >>>>>>> a(t) = a_0 exp(t sqrt{Λc^2/3}). >>>>>>> >>>>>>> The factor sqrt{Λc^2/3} ~ 10^{-18}sec^{-1}. For a billion years this >>>>>>> is t ~ 3x10^{16} sec and so sqrt{Λc^2/3}t ~ .03 and the scale factor >>>>>>> increases by 1.03. The CMB microwave background will be expanded by a >>>>>>> small >>>>>>> change. In 10 billion years this is t ~ 3x10^{17}sec and so >>>>>>> sqrt{Λc^2/3}t ~ >>>>>>> .3 and the scale factor expands by 1.4. At 100 billion and a trillion >>>>>>> the >>>>>>> scale factor expands by 20 and in a trillion years by 10^{13}. This >>>>>>> means >>>>>>> the CMB peak wavelength will be about 10^{10}m. That is not quite the >>>>>>> length of the cosmos, but in 10 trillion years the expansion factor is >>>>>>> close to ~ 10^{800} which means the wavelength at this point is larger >>>>>>> than >>>>>>> the cosmological horizon scale. At that point the CMB will be removed >>>>>>> from >>>>>>> the view of any observer. The time where wavelength becomes longer than >>>>>>> the >>>>>>> cosmological horizon occurs in about 2 trillion years. >>>>>>> >>>>>>> LC >>>>>>> >>>>>> >>>>>> *Does the CMB just keep getting progressively redder as the cosmos >>>>>> expands, or does it actually "wink out", meaning CMB photons which we >>>>>> might >>>>>> eventually observe, begin their journey beyond our horizon? Since no new >>>>>> ones are being created, and the original ones are within our immediate >>>>>> neighborhood, like Andromeda, I don't see how they can wink out. AG * >>>>>> >>>>> >>>>> Think of a cube with sides length L. This is a region that permits >>>>> wavelengths of λ = L/2, L, 3L/2, ...as standing waves. By this as one >>>>> photon of those wavelength leaves another enters. So we can think of >>>>> space >>>>> as having properties similar to a resonance cavity. As space expands this >>>>> box expands, which means the permitted standing waves have longer >>>>> wavelength. So as space expands electromagnetic waves within it also >>>>> becomes stretched. This is the red shifting of light. >>>>> >>>>> Local clusters of galaxies that are gravitationally bound will not >>>>> have this issue. These galaxies will remain in relative close proximity. >>>>> If >>>>> it were not for the fact Andromeda and the Milky Way are going to >>>>> coalesce >>>>> in about 4 billion years Andromeda would be observable from this galaxy >>>>> far >>>>> into the future in wavelengths of light emitted by stars. The other >>>>> galaxy, >>>>> M33 or Triangulum, the smaller of the three large galaxies in the local >>>>> group, may orbit around this newly formed Androway or Milkomeda galaxy >>>>> for >>>>> a nearly indefinite time into the future. >>>>> >>>>> LC >>>>> >>>> >>>> *So you agree with Brent that the CMB will grow redder as the universe >>>> expands, but will never "wink out" as will be the case for galaxies not >>>> gravitationally bound to the MW? The key difference is contained in the >>>> concept of photons entering the box as others leave, and I suppose this >>>> follows from the omnidirectional nature of the CMB. Correct? AG* >>>> >>> >>> Once the wavelength of CMB radiation has expanded beyond any possible >>> quarter wave stack size it it no longer detectable. Once it has expanded to >>> a scale larger than the cosmological horizon it is absolutely impossible to >>> detect. In that case we can say the CMB has winked out. This will happen in >>> a finite time in the future, though two trillion years is 144 times the age >>> of the universe now and almost eternity compared to our lifetimes. In the >>> extreme time frame beyond from 10^{30} to 10^{110} years there will only be >>> supermassive black holes. The cosmological horizon does emit Hawking-Gibbon >>> radiation that is analogous to Hawking radiation. This radiation will >>> perturb black holes, and potentially a civilization or collective of >>> intelligent life that lives around such a SMBH using its angular momentum >>> as energy might be able to detect this perturbation. The SMBH might not >>> decay quite as it would in a pure vacuum. This might be the detection of >>> the cosmological horizon. I will refrain from much comment on the >>> plausibility of such civilizations. >>> >>> The box argument in part works because of the isotropy of the CMB >>> radiation. >>> >>> LC >>> >> >> *What is a quarter wave stack? I get the key point. TY. Since the CMB is >> ubiquitous and isotropic, it can't be treated like a source which becomes >> located beyond the cosmic horizon. AG * >> > > An organ pipe is a quarter wave stack. It has open and closed, or Newman > and Dirichlet, boundary conditions on either end. That way it is resonant > with a wavelength by being a quarter of a wavelength in dimension. > > LC >
*Standing waves in an expanding box is a plausible model for analyzing the evolution of the CMB, but in reality the photons comprising the CMB don't bounce off a barrier, but keep moving away from the source event, some 380,000 years after the BB. How would you overcome this deficiency in your model? TIA, 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 post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
