As many of you are aware, I have serious problems in the application of infinity. and related infinite descriptions, to non-mathematical (reality) situations. Here is a post from 2022:

I am delighted to find that serious attention is being drawn to these difficulties by Open University texts published by Cambridge University Press. Here is just a start from what I have been so pleased to read regarding cosmology, and the problems arising from

In the OU text on

and

I am still reading further and will add as appropriate.

Cat

## Question - BIG BANG EVIDENCE

strophysics > Cosmology and Nongalactic Astrophysics [Submitted on 22 Apr 2022] How the Big Bang Ends up Inside a Black Hole Enrique Gaztanaga The standard model of cosmology assumes that our Universe began 14 Gyrs (billion years) ago from a singular Big Bang creation. This can explain a vast...forums.space.com

Why do you bring infinity into it? The CMB is good evidence of BB theory, which can be dated back to approx. 13.8 billion ya. I do not believe that science can support the idea of a singularity. Any ideas of division by zero (in GR), giving infinite density and temperatures is unsupportable.

No one knows what happened at t = 0 (where the singularity would be). There are ideas (and only ideas) about what might have occurred. One idea (and it is just imaginary) is that, at t = 0), there may have been a nexus, perhaps associated with cyclic process similar to a final 'black hole leading to a big bang, continuing a cyclic process. Some might call this infinite, but infinity is a mathematical term, which has no correspondence with reality. But no one knows what happened. Any idea of a singularity is definitely 'out'.

I am delighted to find that serious attention is being drawn to these difficulties by Open University texts published by Cambridge University Press. Here is just a start from what I have been so pleased to read regarding cosmology, and the problems arising from

*division by zero*and like mathematical operations and trying to apply the results to reality.In the OU text on

*Galaxies and Cosmology*we find:. . . . . . the cosmic microwave background and the expansion of the Universe imply that there was an early phase of the history of the Universe which was characterized by high temperatures and high densities . . . . . . A natural question to ask then is how far back towards t = 0 can we go in understanding processes in the Universe.

and

. . . . . . the Friedmann equation gives a model for a radiation dominated Universe that is characterized by the scale factor having a value of zero at the instant of t = 0 . . . . . . the naive interpretation of this is that the Universe came into existence with an infinitely high temperature; the truth of the matter is that we don't really understand the physical processes in the very early Universe

So, how early in the history of the Universe can we be confident that our physical theories really do apply? There are essentially two answers . . . . . .

Goodbye INFINITE temperatures and densities etcetera.The first is to say that the theories are only well tested for the ranges of physical conditions that can be explored by experiments. Thus, we have a good deal of confidence in describing the Universe at times when the particle energies were similar to the highest values that can be imparted in large accelerator experiments .

(A second approach) is to apply physical theories to conditions that never have been, and probably never will be, tested in the Earth-bound laboratory and to look for observable consequences in Nature. Clearly, this is a more speculative approach than having to rely on 'tried and tested' physical theory.

While it might be expected that physical theories could be extrapolated to describe processes at ever increasing temperatures, it turns out that there is a limit to out theoretical understanding of the processes of Nature . . . . . .

I am still reading further and will add as appropriate.

Cat

Last edited: