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Physics, Astronomy & Cosmology / Can a black hole exist inside another black hole?
« on: 24/02/2014 09:05:22 »
Hello everone,
I had a question regarding the possibiliy of a black hole existing inside another black hole.
Theoretically, an objet that goes through the horizon of a black hole sees nothing special ( except for the firewall theory but let's keep things simple for now ).
That should also be true for a black hole in particular. Lets take the example of a small black hole, let's say of stellar mass, falling in a very large black hole like a galactic black hole. At the horazon of the galactic black hole the gravitational field is not very strong and space is flat at its horizon.
When the small BH enters the large one, its gravitationnal field adds to that of the large one, so obviously the large one has a stronger gravitionnal field and its horizon expands accordingly. The 2 black hole can be said to "merge". However the small black hole remains intact inside the large one.
In other words a photon trapped inside the small black hole continues to be trapped inside that small region of space-time after the small black hole has fallen into the large one.
As for what happens to the small black hole once inside the large one, I don't know but I guess several possibilities could be imagined, such as:
- when the small BH gets close to the center the gravitationnal field becomes so strong that the small BH is torn apart and destroyed.
- the small BH evaporates before it gets to the center
- the small black hole swallows all the matter located in the center and grows until all the content of the large BH in the center has been swallowed and thus it becomes the large BH.
I guess that scientists have already thought about that kind of things, so I was wondering if you knew what they thought was happening.
Thank you,
Regards,
Nic321.
I had a question regarding the possibiliy of a black hole existing inside another black hole.
Theoretically, an objet that goes through the horizon of a black hole sees nothing special ( except for the firewall theory but let's keep things simple for now ).
That should also be true for a black hole in particular. Lets take the example of a small black hole, let's say of stellar mass, falling in a very large black hole like a galactic black hole. At the horazon of the galactic black hole the gravitational field is not very strong and space is flat at its horizon.
When the small BH enters the large one, its gravitationnal field adds to that of the large one, so obviously the large one has a stronger gravitionnal field and its horizon expands accordingly. The 2 black hole can be said to "merge". However the small black hole remains intact inside the large one.
In other words a photon trapped inside the small black hole continues to be trapped inside that small region of space-time after the small black hole has fallen into the large one.
As for what happens to the small black hole once inside the large one, I don't know but I guess several possibilities could be imagined, such as:
- when the small BH gets close to the center the gravitationnal field becomes so strong that the small BH is torn apart and destroyed.
- the small BH evaporates before it gets to the center
- the small black hole swallows all the matter located in the center and grows until all the content of the large BH in the center has been swallowed and thus it becomes the large BH.
I guess that scientists have already thought about that kind of things, so I was wondering if you knew what they thought was happening.
Thank you,
Regards,
Nic321.