# Hollow Black Holes

1. Oct 13, 2004

### ObsessiveMathsFreak

I read recently about supermassive black holes and how they might even have a density close to that of water!! Far out. It got me thinking about the structures of black holes. Would someone be able to survive, "swimming" in the center of such a body. Of course they'd be crushed but it got me thinking.

What if a black hole, was hollow?

Let's say the material outside of the central hollow of the, say spherical, black hole was large enough to create an event horizon. What happens to those within the 'hollow' of the black hole. Let's say they got their before enough material accummulated to form an event horizon, and lived there dyson sphere style! I'm just adding narrative here! :E

Since the gravity within such a hollow, due to the mass around it, is zero, would bodies inside the hollow feel any gravity due to the black hole, and would they expierience any dilation as a result?

As a further query to tack on at the end, when hawking radiation has 'melted' the black hole away, will everyone still be alive inside? Or will the event horizon give way to a scene from the movie Event Horizon!!
Have a nice halloween!

2. Oct 14, 2004

### Aphex_Twin

Incidentally, I have also been interested in black holes. I am no physicist, far from it, however, from what I understand:

The notions of space and time change inside a black hole. The 3 dimensions of space disapear or have no more meaning as, according to the models, the timelines of all matter entering a BH converges towards the singularity. Not only you can you not escape from a BH once you entered, you can't move backwards, nor sideways, as there is no more "backwards" or "sideways". This also means that a person crossing the event horizon effectively dies even if it has not yet been crushed by the huge gravitational forces.

3. Oct 14, 2004

### CJames

This applies to traditional black holes. However, he is talking about a black hole that somehow formed hollow. In other words, in some strange way the outer wall of a black hole condences, but the inside is hollow and so consists of normal spacetime. I can't think of any mechanism that could produce this. However, if in some strange way it took place, I imagine you would live in a confined three dimensional space surrounded by an event horizon. You wouldn't actually be *inside* a black hole, you would be surrounded by black hole space, and the "singularity" would be some sort of spherical construct. I doubt this is possible, however. I don't believe there would be any way to keep a black hole hollow.

4. Oct 14, 2004

### Aphex_Twin

Ahem... What if instead of a hollow sphere it would be a hollow torus. As I see a spinning BH (kerr?) has a singularity the shape of a torus (I don't yet understand why). Does math even cover the propreties of space inside that singularity? What if the BH were spinning on two axes?

5. Oct 14, 2004

### Taoist

This Black Holes were predicted by relativity yet data or confirmation is still theoretical.

Effects of massive gravity and the effects of the description of a black hole have been observed yet Hawkins variables are still obscured by data.

Basic reasoning can deduce that if matter enters than there should be an exiting if the conversion. 1+1 = -1 is not easy to comprehend.

There have been views that have noted the universe as in its ending stage en route to returning to that singularity proposed in the big bang. Both side of the time gradient of matter have been predicted and observed in particle accelerators. Both in negative and positive vectors this has been observed.

As history dictates what blinders have been fitted usually take a fresh look to reach the next level and suggestions shelve themselves until a seeker takes his chance.

Singularity can be defined by 1 and unless the fourth or mirrors are taken into account then the definition is <1.

The same question arises.... How can that be?

I prefer to reason that what is above is equal to below.