Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: chris on 05/06/2017 23:51:42
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Dean is wondering:
Has anyone given any thought into weather or not elements heavier than uranium are created in black holes, or in the collision of two or more black holes?
Do you think that, if hyper-dense elments can be created, what kind of chances are there that some of this stuff is floating freely around in space? And would these new hyper-dense elements follow the octet rule?
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I wouldn't expect any new matter produced by the collisions of black hole to be observable to us out here (I think it would all stay behind the event horizon(s).
But, collisions of neutron stars is hypothesized to be the source of most of the elements heavier than iron. https://en.wikipedia.org/wiki/Nucleosynthesis
I would guess that they can (and do) produce many elements heavier than uranium, but because none of them are stable for any substantial amount of time (https://en.wikipedia.org/wiki/Transuranium_element), they just fall apart before we can come across them. It is possible that such elements can be detected spectroscopically, if we know what to look for (this is one argument for trying to make extremely heavy atoms in particle colliders.)
As far as the octet rule goes. We already have many examples of elements that don't obey the octet rule.
Hydrogen and helium are notable because they only have a 1s orbital that can be populated by electrons (essentially following a 'duet rule' or two electron rule).
Boron formally has only 6 electrons around it in many boron compounds (though one could argue that because most of these compounds are reactive that this argues in favor of the octet rule)
Elements in the third and fourth rows of the periodic table follow the '18 electron rule' (https://en.wikipedia.org/wiki/18-electron_rule though there are many examples of stable compounds with 16 electrons. Going even farther down the periodic table results in even larger numbers of electrons being considered in the valence shell.
Actually, this is one of the things that the periodic table is great at demonstrating. Both elements in the first row follow the 2-electron rule. Each of the next rows contains 8 elements, each of which obey the 8-electron rule. The next two rows have 18 elements each (folwoing the 18-electron rule). Then next two rows have 32 elements each, and follow 32 electron rules (ish). Actually the rules break down somewhat the farther down you go (they're rules of thumb anyway), but essentially however many elements are in a row of the periodic table each want to have that many electrons, or none.
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elements heavier than uranium are created in black holes?
It is thought that the singularity at the core of a black hole would crush atoms so they are no longer recognizable as the familiar protons, neutrons and electrons - so there would not really be elements as we know them. But the inside of a black hole is a strange place, and we really can't tell what is happening from the outside.
However, there is a sense in which a neutron star is like a massive nucleus, with zillions of neutrons and a smaller number of protons and electrons, all held together by gravity. However, there are various theories about what happens at the center of a neutron star - some suggest that the pressure there is so great that individual protons and neutrons would lose their individual identities.
A new NASA space telescope (NICER, launching about now) is intended to study the internal structure of neutron stars, using careful timing and single-photon spectral analysis of pulsars. It will be mounted on the ISS.
See: https://www.nasa.gov/feature/goddard/2017/new-nasa-mission-to-study-mysterious-neutron-stars-aid-in-deep-space-navigation