Is The Universe A Black Hole?

[SaxonViolence]

I read a book by Isaac Asimov two or three decades ago.

 

He said that while Relatively Small Black Holes need to be extraordinarily dense, an Arbitrarily Large Black Hole wouldn't need to be terribly Dense to warp space enough to prevent any light escaping.

 

Then he asked how dense a Black Hole the size of the Known Universe would have to be to have an escape Velocity equal to, or greater than C.

 

The average density would have to be—if I remember correctly—about one Hydrogen atom per Square Meter.....

 

This was very close to our best guestimate as to the Average Density of our Universe.

 

Well, a lot of things have happened in Cosmology since then—like Dark Matter and Dark Energy.....

 

But lets run with Asimov's Conjecture for a Moment.

 

If the Universe is a Giant Black Hole—Where would one expect to find the Singularity?

 

Presumably at the Center—but I thought Relativity ruled out the Universe having a Center.

 

Our Black Holes—how do we rationalize a Black Hole inside a Black Hole?

 

Could a Black Hole be the Universes Singularity?

 

Is it conceivable that each and every Black Hole is Connected somehow in "Higher Dimensions" for want of a better term?

 

What do y'all think?

 

 

Saxon Violence

[Aethelwulf]

Yes the universe could be a black hole.

 

The radius of a black hole is found to be directly proportional to its mass.

 

[math](R \propto M)[/math]

 

The density of a black hole is given by its mass divided by its volume,

 

[math](\rho =\frac{M}{V})[/math]

 

... and since the volume is proportional to the radius of the black hole to the power of three,

 

[math](V \propto R^3)[/math]

 

then the density of the black hole is inversely proportional to its mass raised by the second power.

 

[math](\rho \propto M^2)[/math]

 

This means that from inside a black hole, the universe would not appear to be very dense (and indeed ours is not) since matter only consumes a said 1% of all spacetime. Outside a black hole, the system would appear to be very dense, but the relativistic equations dictate that anything inside of it would not experience this. A most frequent question is

 

''but if this is the case, wouldn't we be dragged towards the singularity? The answer is not if we are stuck inside a special type of inner Horizon which is predicted by black hole theory. If you are stuck inside the first horizon, you will be dragged towards the singular region at it's center because space is now timelike (meaning you are only moving in one direction, and time spacelike (meaning you can now move in time as freely as you had moved in space). However, if you are lucky enough, you may manage to fall into one of these ''safe'' horizons where space and time take on their usual coordinate roles. In other words, the universe we live in would be indistinguishable to the black hole scenario just recited.

Edited December 6, 2012 by Aethelwulf