taking into account that time travels at roughly half speed when orbiting a supermassive blackhole, as mass 'drags' on time, could it be possible to exploit this fact to preserve items for use in the future?(source; Stephen Hawking's Universe)

How long does it take for a black hole to fully form? 

If time appears to "stand still" at the centre of a black hole (from an outsiders point of view), does this mean that it takes forever for a singularity to form (as far as the rest of the universe is concerned)?

Or does the horizon make this problem go away?

The universe is obviously more massive than every existing black hole put together - therefore a split second after the big bang, the universe would have been massive enough to be a black hole by itself, and would also have been small enough to be contained within its own event horizon. As nothing can escape from its own event horizon, how then did the universe manage to expand?

As a stellar body collapses any angular momentum is conserved and shows itself as an increasing rate of rotation - it spins up. Isn't it true then that as a large body collapses down it will spin up without energy loss; particularly if it's a black hole where energy losses within the event horizon are effectively zero. As the collapse continues the central body will spin up to relativistic speeds and, at that point, won't the collapse slow (even inside the horizon) similarly to the so-called 'millisecond pulsars'?

We've all seen gravity described as a bend in spacetime - usually depicted in tv programmes as a couple of large marbles on a square marked rubber membrane. But surely these impossibly deep gravity wells have one overlooked facet - no matter what the celestial object is, the gravity at the centre has to be zero (granted massively huge pressures - but with equalivant gravitation pull outwards)? Meaning there should be a small but significant spike upwards on those maps - ie there is 'zero g' at the absolute centre of a black hole.

If all the matter in the universe was once in a singularity which expanded with the Big Bang to the size it is now, then surely the density of matter initially exceeded the threshhold to create a black hole.

If such is the case, then don't we all live within one massive black hole and the physics that we see are the physics that operate within a black hole?

And if there are smaller blackholes within our observable universe, then surely it is reasonable to assume that there is physics that operates within those blackholes that is similar to our own.

This leads me to think of 2 pretty cool outcomes.

1) there can be an infinite number of blackholes within blackholes and that our observable universe exists as a just one blackhole in a universe of a larger scale just as we have many black holes within our observable universe.  Kind of like infitie Russian Dolls.

and

2) it is possible that the observable universe can both expand to reach the scale and density equilibrium required to one day equalize with the space it occupies in the next higher up scale universe.  Balance could be achieved through the mechanism of matter falling into the Black Hole and hawking radiation out of it along with the gradual expansion.

Does it also mean that the gravity of the next higher scale universe is pulling the matter in this blackhole universe that we live in apart?  Is it the missing Dark Energy?  Is that the dimension where gravity leaks?

I wish I knew some cosmic mathematics to delve deeper into these ideas.  But I'm sure someone who does can tell me why I'm wrong and why a singularity can expand, can even inflate, without bending any rules of blackholes.

Regards,

Kevin

I have heard that black holes have a finite mass but no size and they most likely contain singularities which have infinite mass. How can a finite mass object contain infinite mass? Or am I thinking the question wrongly?

If me and a friend head to the event horizon of a local black hole and hold hands really tightly, what happens if they put their head through the horizon, take a look and then have me pull them out?

As I understand it a black hole can be connected to several universes at once, does this mean that it could in theory consume enough matter to become a super dense and collapse to form a singularity which in turn could generate a Big Bang thus creating a new universe ? 

Also, at what time after the big bang would the universe have been this size? And since nothing can escape a black hole, not even light, how did the universe grow bigger than this? And since the laws of physics break down inside a black hole, how has the behaviour of the universe been extrapolated back to earlier, denser states?