Finitism and Cosmology

> [jim]: 10E80 cubic meters is actually a bigger volume than the BB allows at the current era. The number of galaxies in that volume is ~3x10E12 allowing an average of 10E19 cubic lightyears of space per galaxy. This can be adjusted to what ever volume is correct and the basic fact remains that the totals don't come out anywhere near the model. The BB is well designed and should have an explaination of why all the mass required by the calculations is 1/3rd the mass observed.

It appears that you forgot that space is not uniform in the BB. Near us, the volume inside a sphere of radius 2 Mpc is 8 times the volume inside 1 Mpc -- the standard amount for uniform space. However, in the BB, as we look farther out, the farther we look back in time when the volume of the entire universe was much smaller. So the volume inside a sphere of radius 2 Gpc is *not* eight times the volume inside 1 Gpc, but is appreciably less than that. And as the sphere considered approaches the Hubble radius, the incremental volume approaches zero. Then there is no more space at all beyond that distance.

So your galaxy count estimate is way too high because you asume more volume than exists in the BB universe. -|Tom|-

Not a too shabby explanation, but, my sample of 10E80 is just a representive portion of the universe and the BB model will get to that volume all in the fullness of time. When that happens the mass will still be the same and the model will have way too little mass for the theory to work. The volume going the other direction is smaller and the mass is the same so at some point in the very distant past the process would have reversed and the contraction would have begun maybe way back when the quasars were glowing.

> [jim]: my sample of 10E80 is just a representive portion of the universe and the BB model will get to that volume all in the fullness of time. When that happens the mass will still be the same and the model will have way too little mass for the theory to work.

The BB doesn't require some minimum mass to "work". It just requires that the matter content parameter plus the cosmological constant parameter sum to unity. Right now, these are supposedly 0.3 and 0.7, respectively. As the first of these numbers goes down, the second can go up to keep the balance.

In simple terms, that just means that the universe is expanding (in BB), the expansion is accelerating (as recently announced), and the acceleration will increase in the future. -|Tom|-

If these issues can only be researched in BB concepts it would be good to know the volume of the universe according to BB theory. It is less than 10E80m3 by a lot. I wonder if there is a way to get the volume estimate? It must be less then 10E70m3 or more than 10E68, but, does the BB even have volume perameter? It seems to have only one real dimension-time and everything else like the radius and volume are not really there.

> [jim]: If these issues can only be researched in BB concepts it would be good to know the volume of the universe according to BB theory. It is less than 10E80m3 by a lot. I wonder if there is a way to get the volume estimate? It must be less then 10E70m3 or more than 10E68, but, does the BB even have volume perameter? It seems to have only one real dimension-time and everything else like the radius and volume are not really there.

You are correct that the BB does not specify these parameters such as volume. That is because the "volume" we see is not the volume today, but rather a combination of volume today in our neighborhood plus past volumes at other distances, in accord with the "look-back time".

In the Meta Model, volume is simply 4/3 pi * (distance)^3, as you would expect. However, the relationship between distance and redshift is quite different than in BB, especially at large redshifts. -|Tom|-

That the BB model has no dimensions related to volume seems to imply there is little to connect the real universe to the model. But, thats ok because it is only a model and its main usefulness is not effected by this. But, according to the story that goes will the model the universe was very small ~12 billion years ago. So, maybe there is a way to determine what the volume is using BB rules. I don't know how this can be done since it expands very slowly relative to light speed and stuff observed at ~z=5 or so is not at a distance that redshift indicates. So that cannot be used to indicate distance because the universe is not that big according to theory.