From Aeon to Zeon to Zeit, simplifying the standard cosmic model

[RyanH42]

Ok.I am in holiday and here there's really nothing to do.Nothing

 

[marcus]

I am guessing that your time zone is near UTC or european central. It is 8am pacific, so maybe where you live is 16h, or 4pm? or maybe 5 pm?
I don;t have anything I need to do for the next 2 hours.
We could take up another standard concept---the "particle horizon".
but I want your Mom to be happy.

 

[RyanH42]

S=0 means infinty isn't it.I means S=1/a(t) If a(t) goes infinity S goes zero.

 

[marcus]

Yes that's right, it is just another way to do the same integral, but without having to say "sinh"
Real world human relationships are obviously very very important. Please ignore what I say about particle horizon if there is a risk of making your mother unhappy. Any of this "horizon" business can wait till tomorrow or another day.

Let's try
((s/1.3)^3+1)^(-1/2) between 1 and inf
That is going back in time, from the present, back to very early (large S)

Yes! that works. That gives what cosmologists call the present "radius of the observable universe"
You can see it is 2.69.

It is the distance from us NOW of the farthest matter which could have sent us a signal, some light, some neutrinos, some gravity waves, anything, which is arriving today.

this distance is also called "particle horizon" because it is the farthest distance any particle can have traveled (helped by expansion) starting at the earliest time, at the beginning of expansion.

$${\scriptsize\begin{array}{|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|r|} \hline a=1/S&S&T (zeit)&D_{now} (lzeit)&D_{then}(lzeit)&D_{hor}(lzeit)&D_{par}(lzeit) \\ \hline 1.000&1.000&0.796948&0.000000&0.000000&0.952155&2.675083\\ \hline \end{array}}$$

 

[RyanH42]

Yes We can do

 

[RyanH42]

The problem is am a shy person .I don't have any friends.

 

[RyanH42]

Ok.Lets do this not today.Maybe tomorrow.You can write what you need to write (so you can ready to teach me)

 

[marcus]

Tomorrow is good. I live at the edge of the city near some open country, and some hills with only trees, grass, birds, deer,...
I walk.
It is good exercise. I sometimes get my neighbors to walk with me. It is easy to be with them when we are walking in Nature. looking at the sky and the hills, and the water. The purpose is to get some exercise. The neighbor knows it is for her good health or his good health. So there is a purpose to going on the walk. Either alone or with a companion. I will go walking this morning, with a neighbor who is a retired university professor. She used to teach language, or linguistics. It is an easy way to be with people, when there is a purpose, and a natural environment.