can a black hole exist inside of another black hole?

[alan2here]

As I understand it if you fell into a black hole then you would see the rest of the universe speed up dramatically, more and more as you get to the center and observers outside would see you taking a long time to his the center, giving them a verry long time to save you, unfortunatly they would not be able to do so after you got past the event horizon.

 

So a black hole I supose could appear to be sitting next to another one for a long time.

 

I understood that they are solid in the middle, do they have an "inside"?

[jamey2k9]

I dont think so but I do know something about how two black holes circle each other for ages and then eventually there gravitational pull pulls them together and they merge think of getting two blobs of clay and sticking them together the size increases but only one remains

[J.C.MacSwell]

If you had a small blackhole and a much greater amount of mass "fell" from all directions toward it, at some point you would have a second event horizon form.

 

The first would not immediately disappear and by definition you would have two Black Holes. You could "safely" orbit the inner one while waiting for your demise.

[Martin]

Yes.

 

I agree with MacSwell on the general issue, but probably not at the level of detail.

 

The simplest situation would be a small (solar mass) BH which falls in thru the event horizon of a supermassive (million solar mass) BH.

 

The diameter of the big hole is say 6 million km. The diameter of the solarmass hole is only say 6 kilometers.

 

At first the small BH doesn't even know it has passed in thru the horizon.

 

Eventually its pit will coalesce with that of the more massive.

 

But temporarily there would be a nesting of event horizons.

 

I could be wrong. There have been some computer simulation studies of BH coalescing. We should check the literature.

 

MacSwell would you be willing to do the search?

Here is a place to start:

http://arxiv.org/abs/0902.0136

An improved analytical description of inspiralling and coalescing black-hole binaries

Thibault Damour, Alessandro Nagar

(Submitted on 2 Feb 2009 (v1), last revised 19 Mar 2009 (this version, v2))

"We present an analytical formalism, within the Effective-One-Body framework, which predicts gravitational-wave signals from inspiralling and coalescing black-hole binaries that agree, within numerical errors, with the results of the currently most accurate numerical relativity simulations for several different mass ratios. In the equal-mass case, the gravitational wave energy flux predicted by our formalism agrees, within numerical errors, with the most accurate numerical-relativity energy flux. We think that our formalism opens a realistic possibility of constructing a sufficiently accurate, large bank of gravitational wave templates, as needed both for detection and data analysis of (non spinning) coalescing binary black holes."

Comments: 5 pages, 5 figures, to apper as a Phys. Rev. D Rapid

 

==============

 

I haven't looked at this, but I can attest that Thib Damour is top notch. And the thing is already accepted for peerreview publication. So the quality must be OK.

 

Now this might not be the ideal paper on the subject, but it is recent and it will have footnotes and references to earlier papers.

If you check out some references you may find a review paper that gives some pictures of the computer simulation output of merging black holes.

 

Or maybe somebody else has a better idea of how to check this out.

 

The ideal would be a computer animation movie of a BH merger. I seem to recall seeing one, but I've forgotten where, lost track of the link.

Edited April 21, 2009 by Martin

[J.C.MacSwell]

I agree with MacSwell on the general issue, but probably not at the level of detail.

 

The simplest situation would be a small (solar mass) BH which falls in thru the event horizon of a supermassive (million solar mass) BH.

 

The diameter of the big hole is say 6 million km. The diameter of the solarmass hole is only say 6 kilometers.

 

At first the small BH doesn't even know it has passed in thru the horizon.

 

Eventually its pit will coalesce with that of the more massive.

 

But temporarily there would be a nesting of event horizons.

 

I could be wrong. There have been some computer simulation studies of BH coalescing. We should check the literature.

 

MacSwell would you be willing to do the search?

Here is a place to start:

http://arxiv.org/abs/0902.0136

An improved analytical description of inspiralling and coalescing black-hole binaries

Thibault Damour, Alessandro Nagar

(Submitted on 2 Feb 2009 (v1), last revised 19 Mar 2009 (this version, v2))

"We present an analytical formalism, within the Effective-One-Body framework, which predicts gravitational-wave signals from inspiralling and coalescing black-hole binaries that agree, within numerical errors, with the results of the currently most accurate numerical relativity simulations for several different mass ratios. In the equal-mass case, the gravitational wave energy flux predicted by our formalism agrees, within numerical errors, with the most accurate numerical-relativity energy flux. We think that our formalism opens a realistic possibility of constructing a sufficiently accurate, large bank of gravitational wave templates, as needed both for detection and data analysis of (non spinning) coalescing binary black holes."

Comments: 5 pages, 5 figures, to apper as a Phys. Rev. D Rapid

 

==============

 

I haven't looked at this, but I can attest that Thib Damour is top notch. And the thing is already accepted for peerreview publication. So the quality must be OK.

 

Now this might not be the ideal paper on the subject, but it is recent and it will have footnotes and references to earlier papers.

If you check out some references you may find a review paper that gives some pictures of the computer simulation output of merging black holes.

 

Or maybe somebody else has a better idea of how to check this out.

 

The ideal would be a computer animation movie of a BH merger. I seem to recall seeing one, but I've forgotten where, lost track of the link.

 

Homework, Ouch! That is what I'm here trying to avoid!

 

(actually it's been quite a while since I was a student)

 

I agree that your scenario is much simpler. In fact if Supermassive Black holes exist, and Black Holes are at all common, it would probably unlikely for the Supermassive BH's not to have smaller BH's meander into their event horizon now and then.

 

I will try to remember your link and look it up when I get a chance.

[Airbrush]

Since they suspect binary neutron stars merging to cause the short gamma ray bursts (GRB), then could binary black holes produce the same effect? Each black hole drags an accretion disk into the other black hole. Could that energy released be comparable to neutron stars merging?

 

From wiki:

"Most GRBs appear to be collimated emissions caused by the collapse of the core of a rapidly rotating, high-mass star into a black hole. A subclass of GRBs (the "short" bursts) appear to originate from a different process, the leading theory being the merger of neutron stars orbiting in a binary system."

[Kygron]

I think it's important to remember perspective, especially with relativity.

 

From the perspective of an outside observer, anything entering a black hole becomes part of it, end of discussion. There's really no inside or outside, just a value of mass.

 

From the perspective of someone falling into a black hole, you don't even notice the horizon. Eventually you'll get stretched out, but before that there's no reason why anything that exists in normal space can't exist in "falling space", including other black holes.

[universe2009]

A black hole has nuclear density. Black hole into black hole is vary bad explanation. There are neutrons and insignificant amount protons.