Say hypothetically an UMBH with 50 billion solar masses (supposedly upper limit) is beginning to merge with another (Super)MBH similar to Sagittarius A* that sits at the center of the Milky Way Galaxy, what would happen next in this clash of the titans?
-
$\begingroup$ Similar questions here: astronomy.stackexchange.com/questions/2111/… and astronomy.stackexchange.com/questions/12044/… $\endgroup$– userLTKJan 7, 2016 at 5:40
-
$\begingroup$ and related, as two supermassive black holes are only likely to meet when two galaxies merge. astronomy.stackexchange.com/questions/13013/… $\endgroup$– userLTKJan 7, 2016 at 5:42
-
$\begingroup$ @userLTK: mine is concerning the theoretical upper limit for the size of a black hole which is cap at 50 billion solar masses give and take a couple billion, I wish to know what would happen if an already bloated UMBH is subjected to force feeding... unless all black holes are truely bottomless! $\endgroup$– user6760Jan 7, 2016 at 5:51
1 Answer
From this article:
“Bigger black hole masses are in principle possible – for example, a hole near the maximum mass could merge with another black hole, and the result would be bigger still. But no light would be produced in this merger, and the bigger merged black hole could not have a disc of gas that would make light.”
The theoretical size limit has to do with the ability to form an accretion disk, not the hole itself. While it's probably an extremely rare occurrence due to space expansion, if a 50 billion solar mass black hole was to merge with another 50 billion solar mass black hole, you'd have a 100 billion solar mass black hole. There might be some interesting spiraling in towards each other and some gravitational waves made in the process. It would be cool to study, but in such a scenario, there's no force that would prevent the two black holes from merging into a bigger black hole.