6 ms·

Ancient Stars Made Extraordinarily Heavy Elements (2023)

130 points by samch 3y ago

Erlangen 3y ago
The paper on archive: https://arxiv.org/abs/2312.06844 https://arxiv.org/abs/2312.06844
teekert 3y ago
Just today I was listening to this very nice podcast on the subject: [0] [0] https://podverse.fm/episode/HCgiHwGBC https://podverse.fm/episode/HCgiHwGBC
GMoromisato 3y ago
Still rooting for an Island of Stability: https://en.wikipedia.org/wiki/Island_of_stability https://en.wikipedia.org/wiki/Island_of_stability
- JumpCrisscross 3y ago
  I raise you a continent [1]. [1] https://en.wikipedia.org/wiki/Continent_of_stability https://en.wikipedia.org/wiki/Continent_of_stability
  - mjw_byrne 3y ago
    I'd heard of the island of stability but this one is new to me. I love the idea of there being loads more exotic elements to play with, and substances with densities far exceeding 22 kg/l (which it roughly where it tops out with currently-available elements).
    - idontwantthis 3y ago
      I wonder if USPS would raise their flat rate shipping weight limit.
- thriftwy 3y ago
  It is likely that it does not exists, otherwise we will be seeing these nucleotides in earth crust.
  - JumpCrisscross 3y ago
    > likely that it does not exists, otherwise we will be seeing these nucleotides in earth crust Source? We don’t know these elements’ half lives to an order of magnitude of orders of magnitude. How could we predict their concentration in our crust?
dotancohen 3y ago
The headline goes a bit far. They postulate that some elements, e.g. silver, are the result of the fission of extraordinarily high atomic number elements. There are no actual observations of such elements.
- kstrauser 3y ago
  Do we have the technology to observe such elements if they could even possibly exist? I'd guess they'd be the sort of ephemera that would take a gazillion eV to form, then would decay a femtosecond later.[0] If so, creating an atom in the lab may be outside our engineering skills today. [0] Not a physicist. Not your physicist. Not FDA approved medical advice.
  - pfdietz 3y ago
    We've made elements up to mass number 294. https://en.wikipedia.org/wiki/Superheavy_element https://en.wikipedia.org/wiki/Superheavy_element However, the specific isotopes made in the r-process are very neutron rich, right up to the neutron drip line, and I don't believe we've made many of them.
pjungwir 3y ago
Something I've been curious about lately is: why do we find elements on Earth clumped together, for example veins of iron or gold? I can understand coal or oil since that comes from something organic that put it there. But what about elemental substances? When I throw stuff into my blender or spice mixer it gets pretty homogeneous. Surely an exploding star ought to mix things up better than that. So is there something that brings the iron & gold back together again? I don't know if this is a question for an astrophysicist, chemist, or geologist, but I suppose HN has all three. :-)
- photochemsyn 3y ago
  A remarkably large number of minerals (I've heard estimates as high as 2/3 of all mineral forms) are produced via microbiological activity, e.g. selective oxidation, precipitation, etc. A famous example is the natural uranium reactor Oklo from 2 billion years ago (Congo), formed most likely by microbial precipitation of uranium from seepage water. Today people are investigating the use of microbial uranium precipitation to clean up mine tailings, accident sites, waste leakage etc. from the nuclear sector: https://www.sciencedirect.com/science/article/abs/pii/S0304389411011496 https://www.sciencedirect.com/science/article/abs/pii/S03043...
- umvi 3y ago
  I imagine it's sort of like how if you pour a bunch of liquids together (oil, water, etc), even if you blend them up (ignoring emulsification) they will naturally separate into layers based on density, buoyancy, or some other property that causes them to separate again when subject to natural forces.
- thsksbd 3y ago
  Clearly the metals and their oxides phase segregate, so the question is: "Why do you assume that molten rocks mix?" What mental model do you have that leads you to the wrong answer?
  - bee_rider 3y ago
    Their model seems to be that the elements mix like in a blender. It isn’t clear to me if that’s wrong or not. In particular, two seemingly reasonable processes could the that the elements mix, and then have some additional process to separate, or that they simply don’t mix in the first place. In the former case, their model isn’t wrong, it is just missing an understanding of that last process. In general I think it is good to investigate both options: maybe I’m just wrong, or maybe I’m mostly right but am just missing a couple steps. We’ve got lots of people commenting with processes that will sort the elements back out, so I think op was mostly right, just missing a lot of little processes.
TheOtherHobbes 3y ago
Relevant: https://en.wikipedia.org/wiki/Przybylski%27s_Star https://en.wikipedia.org/wiki/Przybylski%27s_Star
deleted 3y ago
[deleted]
simonebrunozzi 3y ago
Atomic mass of at least 260: yes, but... what does it mean? How much would it weight, on Earth, compared to Uranium or Molibdenum?
- hermitcrab 3y ago
  >How much would it weight A pound of it would weigh a pound. ;0) Do you mean how dense would it be? I don't know how well models predict density. But density is not proportional to atomic number or mass. Osmium has an atomic number of 76 and a density of ~23 g/cm^3. Uranium has an atomic number of 92 and a density of ~19 g/cm^3.
willmadden 3y ago
There's some cool science fiction / conspiracy theory out there about antimatter reactors and stable Moscovium 115. Our part of the galaxy is a desert for stable heavy elements.
- bell-cot 3y ago
  An evil alien (Vogon, FWIW) mining company came through a zillion years ago, and stripped our part of galaxy of every last atom of precious unobtainium, leaving poor humanity stuck in the galactic equivalent of the Stone Age forever?
  - willmadden 3y ago
    Sans the lore; look into interviews with Bob Lazar, both from the 80's and recently. His story hasn't changed in decades, and he has nothing to gain from it financially, at least that I can tell. Also, his wikipedia page has been edited into a hit piece against him, which makes the story even more interesting. He predicted the discovery of Moscovium 115 before it was synthesized in an unstable form by Russian scientists. He claimed (and claims) that a stable form of element 115 is the "fuel" in antimatter reactors. It's an intriguing story. There's a Joe Rogan podcast interviewing him.

130 points by samch 3y ago

The paper on archive: https://arxiv.org/abs/2312.06844 https://arxiv.org/abs/2312.06844

Just today I was listening to this very nice podcast on the subject: [0] [0] https://podverse.fm/episode/HCgiHwGBC https://podverse.fm/episode/HCgiHwGBC

GMoromisato 3y ago

Still rooting for an Island of Stability: https://en.wikipedia.org/wiki/Island_of_stability https://en.wikipedia.org/wiki/Island_of_stability

JumpCrisscross 3y ago
I raise you a continent [1]. [1] https://en.wikipedia.org/wiki/Continent_of_stability https://en.wikipedia.org/wiki/Continent_of_stability
- mjw_byrne 3y ago
  I'd heard of the island of stability but this one is new to me. I love the idea of there being loads more exotic elements to play with, and substances with densities far exceeding 22 kg/l (which it roughly where it tops out with currently-available elements).
  - idontwantthis 3y ago
    I wonder if USPS would raise their flat rate shipping weight limit.
thriftwy 3y ago
It is likely that it does not exists, otherwise we will be seeing these nucleotides in earth crust.
- JumpCrisscross 3y ago
  > likely that it does not exists, otherwise we will be seeing these nucleotides in earth crust Source? We don’t know these elements’ half lives to an order of magnitude of orders of magnitude. How could we predict their concentration in our crust?

dotancohen 3y ago

The headline goes a bit far. They postulate that some elements, e.g. silver, are the result of the fission of extraordinarily high atomic number elements. There are no actual observations of such elements.

kstrauser 3y ago
Do we have the technology to observe such elements if they could even possibly exist? I'd guess they'd be the sort of ephemera that would take a gazillion eV to form, then would decay a femtosecond later.[0] If so, creating an atom in the lab may be outside our engineering skills today. [0] Not a physicist. Not your physicist. Not FDA approved medical advice.
- pfdietz 3y ago
  We've made elements up to mass number 294. https://en.wikipedia.org/wiki/Superheavy_element https://en.wikipedia.org/wiki/Superheavy_element However, the specific isotopes made in the r-process are very neutron rich, right up to the neutron drip line, and I don't believe we've made many of them.

pjungwir 3y ago

Something I've been curious about lately is: why do we find elements on Earth clumped together, for example veins of iron or gold? I can understand coal or oil since that comes from something organic that put it there. But what about elemental substances? When I throw stuff into my blender or spice mixer it gets pretty homogeneous. Surely an exploding star ought to mix things up better than that. So is there something that brings the iron & gold back together again? I don't know if this is a question for an astrophysicist, chemist, or geologist, but I suppose HN has all three. :-)

photochemsyn 3y ago
A remarkably large number of minerals (I've heard estimates as high as 2/3 of all mineral forms) are produced via microbiological activity, e.g. selective oxidation, precipitation, etc. A famous example is the natural uranium reactor Oklo from 2 billion years ago (Congo), formed most likely by microbial precipitation of uranium from seepage water. Today people are investigating the use of microbial uranium precipitation to clean up mine tailings, accident sites, waste leakage etc. from the nuclear sector: https://www.sciencedirect.com/science/article/abs/pii/S0304389411011496 https://www.sciencedirect.com/science/article/abs/pii/S03043...
umvi 3y ago
I imagine it's sort of like how if you pour a bunch of liquids together (oil, water, etc), even if you blend them up (ignoring emulsification) they will naturally separate into layers based on density, buoyancy, or some other property that causes them to separate again when subject to natural forces.
thsksbd 3y ago
Clearly the metals and their oxides phase segregate, so the question is: "Why do you assume that molten rocks mix?" What mental model do you have that leads you to the wrong answer?
- bee_rider 3y ago
  Their model seems to be that the elements mix like in a blender. It isn’t clear to me if that’s wrong or not. In particular, two seemingly reasonable processes could the that the elements mix, and then have some additional process to separate, or that they simply don’t mix in the first place. In the former case, their model isn’t wrong, it is just missing an understanding of that last process. In general I think it is good to investigate both options: maybe I’m just wrong, or maybe I’m mostly right but am just missing a couple steps. We’ve got lots of people commenting with processes that will sort the elements back out, so I think op was mostly right, just missing a lot of little processes.

TheOtherHobbes 3y ago

Relevant: https://en.wikipedia.org/wiki/Przybylski%27s_Star https://en.wikipedia.org/wiki/Przybylski%27s_Star

deleted 3y ago

[deleted]

simonebrunozzi 3y ago

Atomic mass of at least 260: yes, but... what does it mean? How much would it weight, on Earth, compared to Uranium or Molibdenum?

hermitcrab 3y ago
>How much would it weight A pound of it would weigh a pound. ;0) Do you mean how dense would it be? I don't know how well models predict density. But density is not proportional to atomic number or mass. Osmium has an atomic number of 76 and a density of ~23 g/cm^3. Uranium has an atomic number of 92 and a density of ~19 g/cm^3.

willmadden 3y ago

There's some cool science fiction / conspiracy theory out there about antimatter reactors and stable Moscovium 115. Our part of the galaxy is a desert for stable heavy elements.

bell-cot 3y ago
An evil alien (Vogon, FWIW) mining company came through a zillion years ago, and stripped our part of galaxy of every last atom of precious unobtainium, leaving poor humanity stuck in the galactic equivalent of the Stone Age forever?
- willmadden 3y ago
  Sans the lore; look into interviews with Bob Lazar, both from the 80's and recently. His story hasn't changed in decades, and he has nothing to gain from it financially, at least that I can tell. Also, his wikipedia page has been edited into a hit piece against him, which makes the story even more interesting. He predicted the discovery of Moscovium 115 before it was synthesized in an unstable form by Russian scientists. He claimed (and claims) that a stable form of element 115 is the "fuel" in antimatter reactors. It's an intriguing story. There's a Joe Rogan podcast interviewing him.