<p>From this <a href="http://scitechdaily.com/black-holes-could-grow-as-large-as-50-billion-suns-before-their-food-crumbles-into-stars-research-shows/" rel="nofollow">article</a>:  </p>

<blockquote>
  <p>“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.”</p>
</blockquote>

<p>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 <a href="https://en.wikipedia.org/wiki/Gravitational_wave" rel="nofollow">gravitational waves</a> 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.</p>

CC BY-SA 3.0
2016-01-07T06:17:27.893Z
2016-01-07T06:17:27.893Z
userLTK
<p>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?</p>

CC BY-SA 3.0
2016-01-07T05:40:55.410Z
Similar questions here:  http://astronomy.stackexchange.com/questions/2111/collision-of-2-black-holes and http://astronomy.stackexchange.com/questions/12044/what-happens-when-two-black-holes-collide
userLTK
CC BY-SA 3.0
2016-01-07T05:42:00.497Z
and related, as two supermassive black holes are only likely to meet when two galaxies merge.   http://astronomy.stackexchange.com/questions/13013/why-do-we-believe-that-the-super-massive-black-holes-at-the-centers-of-two-mergi?rq=1
userLTK
CC BY-SA 3.0
2016-01-07T05:51:10.073Z
@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!
user6760
<supermassive-black-hole>
What happens when an Ultra Massive Black Hole cannibalize another?
user6760
# What happens when an Ultra Massive Black Hole cannibalize another?

(Asked by: username_0 on 2016-01-07)

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?

**Tags:** supermassive-black-hole

> **Comments:**
> **username_1**: Similar questions here:  http://astronomy.stackexchange.com/questions/2111/collision-of-2-black-holes and http://astronomy.stackexchange.com/questions/12044/what-happens-when-two-black-holes-collide  
> **username_1**: and related, as two supermassive black holes are only likely to meet when two galaxies merge.   http://astronomy.stackexchange.com/questions/13013/why-do-we-believe-that-the-super-massive-black-holes-at-the-centers-of-two-mergi?rq=1  
> **username_0**: @username_1: 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!  

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## 1 answers

### Answer by username_1 on 2016-01-07. Score: 1 | Accepted answer

From this [article](http://scitechdaily.com/black-holes-could-grow-as-large-as-50-billion-suns-before-their-food-crumbles-into-stars-research-shows/):

> “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](https://en.wikipedia.org/wiki/Gravitational_wave) 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.


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