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Observations

• The heaviest elements known in abundance in nature are forged deep within stars.




• These elements are made possible by the high densities/pressures within the stars.




• Black holes are known to have a much higher density/pressure than any known star.




• Black holes are also known to be a phase of stellar evolution - this suggests that the original star's internal process of forging metals would persist within the resultant black hole.




• Scientists have forged synthetic/ephemeral heavy metals under conditions which could hypothetically be sustained within a black hole.

Hypothesis:

Black holes forge heavier elements that have not been observed on earth. The conditions needed to sustain these elements are unique to the black hole, due to its high density/pressures. These conditions can be glimpsed, but not sustained in any experimental context

Follow up questions:

• Has this been hypothesized?




• Where can I find research on this topic?

The heaviest elements known in nature are forged deep within stars.

No, the heaviest elements are made on Earth in scientific laboratories, or in the extreme gravity of a neutron star's crust.

These elements are made possible by the high densities/temperature/pressures within the stars.

Many of the larger elements can be made in supernovae and neutron star collisions, not in stars. It requires extreme conditions for these elements to form.

Black holes are known to have a much higher density/temperature/pressure than any known star.

Black holes are actually very cold, they "absorb" any radiation that passes their event horizon. Outside the event horizon may be some very hot material, but it is not actually so hot compared to the core of a star.

Black holes are also known to be a phase of stellar evolution - this suggests that the original star's internal process of forging metals would persist within the resultant black hole.

No, inside the black hole everything falls, and reaches a singularity in a short amount of time.

Scientists have forged synthetic/ephemeral heavy metals under conditions which could hypothetically be sustained within a black hole.

As above, the conditions beyond the event horizon are unlike anything we have on Earth, because there is the unavoidable singularity.

After some matter has crossed the event horizon it will certainly come to the singularity. (in the same way as you will certainly reach tomorrow) And as it gets closer the tidal effects get greater, eventually ripping the atoms apart. The extreme gravity in a black hole will tend to pull matter apart not fusing it to larger atoms.

There may be nucleosynthesis in the accretion disc around a black hole. While the amount of high mass atoms made here is relatively small, it may be useful for the sake of detecting and distinguishing black holes from neutron stars or white dwarfs.

Superheavy elements have short half lives because of their extreme instability with respect to alpha decay and fission. This is a result of their high electric charge, which results in strong forces of electrical repulsion. Although theorists have predicted an "island of stability" due to quantum mechanical shell effects, this stability is a relative thing. We're still talking about half-lives on the order of seconds or less. So any such element created by astrophysical processes will not survive for very long, even if it doesn't fall into the black hole.

So conceivably in the accretion disk, outside the event horizon, you could get some fusion events resulting in the formation of superheavy elements, but those elements would not survive for very long, even if they were somehow ejected rather than infalling past the horizon. And the normal methods for detecting and characterizing superheavy elements would not work here. Normally we look for things like alpha-decay chains with characteristic alpha energies. Those would not be detectable from outside the accretion disk, since charged particles interact strongly with matter and are stopped.

The conditions needed to sustain these elements are unique to the black hole, due to its high density/pressures.

Most of the interior of a black hole (inside the event horizon) is probably an extremely good vacuum. The only high densities and pressures would be near the singularity. So any exotic matter formed at high densities and pressures would not be observable from earth or have any consequences for the outside universe, because nothing can escape from inside the event horizon.

If we were to send a space probe inside a black hole to look for exotic matter being formed near the singularity, the probe would not be able to report its results back. Also, the region of high-density and high-pressure infalling matter would exist near the singularity, which would probably not be detectable to the probe until the probe itself had been destroyed by the same processes. (On the inside of a black hole, if general relativity is correct, you can't see the singularity. You only see infalling photons from the outside.)

If exotic matter is formed near the singularity, it will only exist for a very short time before accreting onto the singularity. (IIRC the maximum infall time for a 10-solar-mass black hole is on the order of milliseconds from horizon to singularity.) We don't really know what happens at the singularity, but we certainly can't have atomic nuclei under those conditions.

The problem of the superheavy elements is not that we can't forge them. Their problem is that they decay very quickly. For example, Oganesson, the heaviest element synthetised until now, has a half life of 181 ms.

In theory, even much heavier elements could be created in particle accelerators, but there is no way to even detect them.

In neutron stars, or in exploding supernovas, all the elements are created, but there is no way to even detect them. We can consider a neutron star as a large nucleus with $approx 10^56$ neutrons.¹

In black holes, the fact is that no one knows, what is in them. They don't radiate anything (with a very little exception), and nothing leaves the singularity in them. To understand what is in them, would require currently unrealistic advances in Physics. The singularity in their center is probably not baryonic matter, though, thus we could hardly say that it would be any chemical element.

¹_{As @PM2Ring's excellent comment says, neutron stars also have a significant number of other particles, too, not only neutrons. I also extend it that they are bound gravitationally and not by the strong interaction, which makes them in this aspect essentially different from nuclei.}

Instead of diving into misdirected debates and bike-shedding, I will answer my own question here with clarity, coalescing some of the useful feedback I've received thus far.

Question

Could Black holes forge heavier elements that have yet to be discovered? Has this been hypothesized? Where can I find research on this topic?

Answer

Yes, and it is hypothesized that they do as they interact with and consume other celestial objects.

Research performed last year at Cornell suggests that some or all of the inventory of r-process nucleosynthesis can be produced in interactions of primordial black holes (PBHs). In nuclear astrophysics, R-process capture is responsible for the creation (nucleosynthesis) of approximately half the abundances of the atomic nuclei heavier than iron.

Feel free to take a look at that research here: https://arxiv.org/abs/1704.01129