Volume of the universe

[no-one-particular]

Assuming that the universe is 1 trillion light years in radius and 100 angstroms in thickness then the volume of the universe is the same as a four dimensional sphere 1,434 light years in radius.

Atoms have volumes of 10-100 ų. Water has a density of 1 gram/cm³ which is 560,000,000 eV/ų. A three dimensional sphere with a density of 0.0056 eV/ų and a radius of 1,434 light years would have a surface gravity of 3.87 g's.

The surface gravity of a four dimensional sphere would be approximately the same or a little bit less.

An object falling from infinity to the surface (or from the surface to the center) would accelerate to 75c

75c * 13.8 billion years = 1 trillion light years

The pressure at the center would be approximately 25.75 million bars which is 7 times the pressure at the center of the Earth.

It is probable that when an object reaches that size its core begins collapsing and emitting energy and that this normally prevents the object from growing further.

 

[steve_bank]

The volume was loud at the BB and tapered off exponentially.

 

[bilby]

When your maths includes velocities greater than c, that's a sure sign that you are doing something wrong - most likely, trying to apply Newtonian physics to a problem that requires Einstinian physics to resolve.

 

[no-one-particular]

When your maths includes velocities greater than c, that's a sure sign that you are doing something wrong - most likely, trying to apply Newtonian physics to a problem that requires Einstinian physics to resolve.

The universe is expanding much faster than the speed of light

 

[steve_bank]

There is no way to know the extents of the universe. We have an observational limit to detect EM radiation. We have no way of knowing what the universe looks from the edge of our detection limits.

 

[no-one-particular]

We can see to the CMB which is 46 billion light years away.
Thats 2.6356° of the way around the entire universe.
Cos(2.6356°) = 0.99894
flat to within 0.1 percent

 

[steve_bank]

We can see to the CMB which is 46 billion light years away.
Thats 2.6356° of the way around the entire universe.
Cos(2.6356°) = 0.99894
flat to within 0.1 percent

The CMB looks like a BB at a low temperature. I don't think it has a location.

 

[Loren Pechtel]

When your maths includes velocities greater than c, that's a sure sign that you are doing something wrong - most likely, trying to apply Newtonian physics to a problem that requires Einstinian physics to resolve.

The universe is expanding much faster than the speed of light

Which has nothing to do with the problem. You're looking at what gravity would do, the expansion of the universe doesn't enter into that (although it could change the final outcome.) Einsteinian math is a lot harder but it's required here.

 

[skepticalbip]

We can see to the CMB which is 46 billion light years away.
Thats 2.6356° of the way around the entire universe.
Cos(2.6356°) = 0.99894
flat to within 0.1 percent

The CMB looks like a BB at a low temperature. I don't think it has a location.

Right. The CMB isn't "out there on the edge". The radiation left from the BB is throughout the universe everywhere. The average temperature of empty space away from heat sources like stars is calculated to be ~3 kelvins