<p>After a google search the answer is yes, in theory. There is nucleosynthesis associated with the Black Hole accretion disks, see <a href="https://wwwmpa.mpa-garching.mpg.de/~grb07/Presentations/McLaughlin.pdf" rel="nofollow noreferrer">here</a>, <a href="https://iopscience.iop.org/article/10.1086/588085/fulltext/72900.text.html" rel="nofollow noreferrer">here</a> and <a href="http://adsabs.harvard.edu/full/2000A%26A...353.1029M" rel="nofollow noreferrer">here</a>. These sources look at the nucleosynthesis in the hotter parts of the accretion disks surrounding black holes, and how this is effected by the neutrinos produced.</p>

<p>It is also proposed that its possible for very small mass (10e-9 Mass of sun) black holes to be devoured by a neutron star (<a href="https://cosmosmagazine.com/physics/primordial-black-holes-may-create-gold-and-other-heavy-elements" rel="nofollow noreferrer">see here</a>) and produce many of the heavier elements. This method starts with primordial black holes which can be of the required mass compacted into a region the size of a single atom. This tiny black hole could crash into a neutron star and initiate the r-process for nucleosynthesis.</p>

CC BY-SA 4.0
2019-07-25T20:39:06.027Z
Great, I'll give these sources read today. Thank you for taking my question seriously!
uhoh
CC BY-SA 4.0
2019-07-26T13:55:55.990Z
Good answer, I will read those documentations more seriously this week-end. Thank you !
Astrea
CC BY-SA 4.0
2019-07-25T17:25:56.087Z
2019-07-25T17:31:40.383Z
2019-07-25T17:31:40.383Z
Natsfan
<p>During its lifetime, a star can synthesize elements to iron because of the pressure and temperature. A neutron star is composed of iron nuclei 56 and up to krypton 118.</p>

<p>According to that, a black hole (which concentrates matter to an increasingly tiny space during infall) must also have an unimaginable pressure/temperature during its formation and as additional matter falls into it.</p>

<p>Can it therefore synthesize new elements? </p>

CC BY-SA 4.0
2019-07-19T20:09:35.170Z
Why do you say a neutron star has iron and krypton? A neutron star is composed of mostly neutrons and a small amount of electrons and protons.   At high temperatures there are too many high-energy gamma rays that photodisintegrate nuclei.
eshaya
CC BY-SA 4.0
2019-07-19T20:12:23.133Z
Please see https://physics.stackexchange.com/a/141876/123208 We don't have a quantum gravity theory, so we can't really talk about the ultimate fate of matter in a BH. But it's likely that atoms falling into a BH get ripped apart, and protons & neutrons probably can't survive either.
PM 2Ring
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2019-07-19T20:19:18.450Z
@eshaya A neutron star has a crust of relatively normal nuclei, albeit rather distorted from the gravity, and those nuclei have higher neutron : proton ratios than normal. Please see https://astronomy.stackexchange.com/a/23173/16685 for further details.
PM 2Ring
CC BY-SA 4.0
2019-07-19T21:06:05.917Z
@Astrea I've modified your question a bit so that it can be answerable. "Is a black hole made of heavy elements" can't really be answered easily, but the fate of matter during it's formation process, and as more matter falls in later might be answerable.
uhoh
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2019-07-19T21:06:34.707Z
@PM2Ring I've made an edit/adjustment, hopefully this is more answerable.
uhoh
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2019-07-19T22:52:50.750Z
@uhoh I still have nothing to say, apart from "Probably not". And it looks like Rob J doesn't want to answer it either. I *guess* you might get some exotic nuclei during the initial collapse, but nothing beyond what happens in a neutron star. And afterwards, infalling matter is too busy being spaghettified to do anything constructive. ;)
PM 2Ring
CC BY-SA 4.0
2019-07-19T23:11:36.257Z
It's probably not consequential, but somehow now I find this really intriguing and metaphoric; does infalling matter have one last chance to do something even if nobody outside the event horizon will ever know? "look at me, I nucleosynthesize, therefore I am!"
uhoh
CC BY-SA 4.0
2019-07-20T23:33:51.357Z
We cannot say what's inside a black hole because nothing escapes it. Around black holes, the energy of infalling material is high, but I doubt it is high enough to synthesize something new. However, it is known that in its creation process, a supernova, new elements are created.
jan.sende
CC BY-SA 4.0
2019-07-22T12:50:15.677Z
Ok, thank you all for your comments and modifications. So we are searching for a quantum gravity theory to be able to better understand what happens in a BH.
Astrea
CC BY-SA 4.0
2019-07-25T15:13:09.713Z
It would be nice to unify physics so that everything can be modeled by a single theory. Currently, we have GR which describes gravity, but which is oblivious to quantum effects, and QM which describes everything else, but which is ignorant of gravity.
PM 2Ring
CC BY-SA 4.0
2019-07-25T15:15:32.833Z
However, there aren't many situations that *need* both GR & QM. The most important is the very earliest moments of the Big Bang (less than a nanosecond); Quantum Gravity should also tell us about the ultimate fundamental nature of spacetime. It will tell us if Hawking radiation is real or not. It will also tell us exactly what goes on at the core of a black hole, but because of the event horizon we will never be able to make observations that allow us to verify those predictions.
PM 2Ring
CC BY-SA 4.0
2019-07-25T16:03:56.263Z
I still think we can answer the question with a "No". We do know that at high pressures and densities, as are already reached in neutron star cores and are much higher than in atomic nuclei, no protons and certainly no regular atoms can exist. I cant see how the further collapse to a BH or quantum-gravity could change that. The only thing that can happen is the r-process outside of the core during the supernova.
SpaceCore
CC BY-SA 4.0
2019-07-26T13:59:30.890Z
@uhoh thank you for boosting this question with bounties !
Astrea
<black-hole><astrophysics>
Does nucleosynthesis happen near a black hole or during its formation?
Astrea
# Does nucleosynthesis happen near a black hole or during its formation?

(Asked by: username_0 on 2019-07-19)

During its lifetime, a star can synthesize elements to iron because of the pressure and temperature. A neutron star is composed of iron nuclei 56 and up to krypton 118.

According to that, a black hole (which concentrates matter to an increasingly tiny space during infall) must also have an unimaginable pressure/temperature during its formation and as additional matter falls into it.

Can it therefore synthesize new elements?

**Tags:** black-hole, astrophysics

> **Comments:**
> **username_1**: Why do you say a neutron star has iron and krypton? A neutron star is composed of mostly neutrons and a small amount of electrons and protons.   At high temperatures there are too many high-energy gamma rays that photodisintegrate nuclei.  
> **username_2**: Please see https://physics.stackexchange.com/a/141876/123208 We don't have a quantum gravity theory, so we can't really talk about the ultimate fate of matter in a BH. But it's likely that atoms falling into a BH get ripped apart, and protons & neutrons probably can't survive either.  
> **username_2**: @username_1 A neutron star has a crust of relatively normal nuclei, albeit rather distorted from the gravity, and those nuclei have higher neutron : proton ratios than normal. Please see https://astronomy.stackexchange.com/a/23173/16685 for further details.  
> **username_3**: @username_0 I've modified your question a bit so that it can be answerable. "Is a black hole made of heavy elements" can't really be answered easily, but the fate of matter during it's formation process, and as more matter falls in later might be answerable.  
> **username_3**: @username_2 I've made an edit/adjustment, hopefully this is more answerable.  
> **username_2**: @username_3 I still have nothing to say, apart from "Probably not". And it looks like Rob J doesn't want to answer it either. I *guess* you might get some exotic nuclei during the initial collapse, but nothing beyond what happens in a neutron star. And afterwards, infalling matter is too busy being spaghettified to do anything constructive. ;)  
> **username_3**: It's probably not consequential, but somehow now I find this really intriguing and metaphoric; does infalling matter have one last chance to do something even if nobody outside the event horizon will ever know? "look at me, I nucleosynthesize, therefore I am!"  
> **username_4**: We cannot say what's inside a black hole because nothing escapes it. Around black holes, the energy of infalling material is high, but I doubt it is high enough to synthesize something new. However, it is known that in its creation process, a supernova, new elements are created.  
> **username_0**: Ok, thank you all for your comments and modifications. So we are searching for a quantum gravity theory to be able to better understand what happens in a BH.  
> **username_2**: It would be nice to unify physics so that everything can be modeled by a single theory. Currently, we have GR which describes gravity, but which is oblivious to quantum effects, and QM which describes everything else, but which is ignorant of gravity.  
> **username_2**: However, there aren't many situations that *need* both GR & QM. The most important is the very earliest moments of the Big Bang (less than a nanosecond); Quantum Gravity should also tell us about the ultimate fundamental nature of spacetime. It will tell us if Hawking radiation is real or not. It will also tell us exactly what goes on at the core of a black hole, but because of the event horizon we will never be able to make observations that allow us to verify those predictions.  
> **username_5**: I still think we can answer the question with a "No". We do know that at high pressures and densities, as are already reached in neutron star cores and are much higher than in atomic nuclei, no protons and certainly no regular atoms can exist. I cant see how the further collapse to a BH or quantum-gravity could change that. The only thing that can happen is the r-process outside of the core during the supernova.  
> **username_0**: @username_3 thank you for boosting this question with bounties !  

---

## 1 answers

### Answer by username_6 on 2019-07-25. Score: 3 | Accepted answer

After a google search the answer is yes, in theory. There is nucleosynthesis associated with the Black Hole accretion disks, see [here](https://wwwmpa.mpa-garching.mpg.de/~grb07/Presentations/McLaughlin.pdf), [here](https://iopscience.iop.org/article/10.1086/588085/fulltext/72900.text.html) and [here](http://adsabs.harvard.edu/full/2000A%26A...353.1029M). These sources look at the nucleosynthesis in the hotter parts of the accretion disks surrounding black holes, and how this is effected by the neutrinos produced.

It is also proposed that its possible for very small mass (10e-9 Mass of sun) black holes to be devoured by a neutron star ([see here](https://cosmosmagazine.com/physics/primordial-black-holes-may-create-gold-and-other-heavy-elements)) and produce many of the heavier elements. This method starts with primordial black holes which can be of the required mass compacted into a region the size of a single atom. This tiny black hole could crash into a neutron star and initiate the r-process for nucleosynthesis.

> **Comments:**
> **username_3**: Great, I'll give these sources read today. Thank you for taking my question seriously!  
> **username_0**: Good answer, I will read those documentations more seriously this week-end. Thank you !  

---

