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> All natural uranium today contains 0.720% of U-235. That's related to the material of our solar system all coming from the same supernova explosion or simila

> All natural uranium today contains 0.720% of U-235. That's related to the material of our solar system all coming from the same supernova explosion or similar, right? Does this apply to our entire milky way or just the solar system? What if parts collided with material of _other_ origins and some of that is on Earth, then there could be different mixes, right?

BurningFrog 1y ago
Grok says: At Earth's formation ~4.5 billion years ago, natural uranium contained approximately 23.2% U-235 These numbers are probably only for the local corner of the galaxy. It depends on when the supernova(s) that created the uranium exploded.
- _Algernon_ 1y ago
  We all have access to Grok and other AI models, and we will ask it if we want it's bullshit hallucinations. There is no point polluting HN with this trash.
  - deleted 1y ago
    [deleted]
  - BurningFrog 1y ago
    Anyone can look it up, yet I was the only one who did.
    - _Algernon_ 1y ago
      You didn't look anything up. You prompted a stochastic parrot.
  - CamperBob2 1y ago
    Is it wrong?
    - joemi 1y ago
      That's a good question. In order to know whether or not the AI was wrong, you'd need to do some research. Otherwise it's about as reliable as any "fact" some random person on the internet claims to be true.
    - _Algernon_ 1y ago
      Talk about missing the point. Why should I spend my time fact checking the output of a glorified, stochastic parrot?
      - CamperBob2 1y ago
        Because your competitors are using it, and they are going to flatten you. Effective tool use is kind of a big deal.
philipkglass 1y ago
It's related to how long ago the uranium was formed: https://world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/the-cosmic-origins-of-uranium https://world-nuclear.org/information-library/nuclear-fuel-c... We can calculate the abundances of U-235 and U-238 at the time the Earth was formed. Knowing further that the production ratio of U-235 to U-238 in a supernova is about 1.65, we can calculate that if all of the uranium now in the solar system were made in a single supernova, this event must have occurred some 6.5 billion years ago. This 'single stage' is, however, an oversimplification... The really interesting thing is that phrase "the production ratio of U-235 to U-238 in a supernova is about 1.65"; the now-rare U-235 is actually more abundant than U-238 in the fresh debris of a supernova. Prolonged aging has preserved more U-238 (half life 4.47 billion years) than U-235 (half life 0.704 billion years) to the point that U-238 is now much more terrestrially abundant. If Earth had been formed with uranium that rich in U-235, there would have been Oklo events all over the place. Uranium wouldn't need isotopic enrichment to be used as fuel in light water reactors. Nuclear fission would probably have been discovered early in the 19th century, soon after the element itself was recognized, because any substantial quantity dissolved in aqueous solution would have reached criticality.
- lazide 1y ago
  It’s interesting to extrapolate that to the early earth - radioactive decay and fission interactions likely play a much larger role than we are able to reliably model. Okla is somewhat unique in that the formation survived for us to dig it up - most from that time would not.
- cryptonector 1y ago
  I read GP's question really as: "did all Uranium on Earth come from the same source?" and your answer implies "yes". I think that's right. The fact that everywhere we see the same U-235/U-238 ratio or very close (Oklo) strongly implies either a single source (supernova) or that if it was more than one source they were all at roughly the same time (6.5 billion years ago), with the latter seeming [to me] less likely, so a single source at 6.5 billion years ago is what makes sense. Unless there were many supernovae and their remnants mixed quite well in our corner of the galaxy where our sun was born.
mandevil 1y ago
This is just in our little corner of the Milky Way, but not thought to be the result of just one supernova. I last looked into this about a decade ago so I might be behind the times, but at that time the most popular theory was that the cloud that became our Solar System was the result of thousands of supernova scattering and mixing atoms, across both the first two generations of stars (the Sun is considered to be a third-generation star), and that mixing is thought to be an important factor in making it complex enough to have rocky inner planets, gaseous outer planets, etc.

BurningFrog 1y ago

Grok says: At Earth's formation ~4.5 billion years ago, natural uranium contained approximately 23.2% U-235 These numbers are probably only for the local corner of the galaxy. It depends on when the supernova(s) that created the uranium exploded.

_Algernon_ 1y ago
We all have access to Grok and other AI models, and we will ask it if we want it's bullshit hallucinations. There is no point polluting HN with this trash.
- deleted 1y ago
  [deleted]
- BurningFrog 1y ago
  Anyone can look it up, yet I was the only one who did.
  - _Algernon_ 1y ago
    You didn't look anything up. You prompted a stochastic parrot.
- CamperBob2 1y ago
  Is it wrong?
  - joemi 1y ago
    That's a good question. In order to know whether or not the AI was wrong, you'd need to do some research. Otherwise it's about as reliable as any "fact" some random person on the internet claims to be true.
  - _Algernon_ 1y ago
    Talk about missing the point. Why should I spend my time fact checking the output of a glorified, stochastic parrot?
    - CamperBob2 1y ago
      Because your competitors are using it, and they are going to flatten you. Effective tool use is kind of a big deal.

philipkglass 1y ago

It's related to how long ago the uranium was formed: https://world-nuclear.org/information-library/nuclear-fuel-cycle/uranium-resources/the-cosmic-origins-of-uranium https://world-nuclear.org/information-library/nuclear-fuel-c... We can calculate the abundances of U-235 and U-238 at the time the Earth was formed. Knowing further that the production ratio of U-235 to U-238 in a supernova is about 1.65, we can calculate that if all of the uranium now in the solar system were made in a single supernova, this event must have occurred some 6.5 billion years ago. This 'single stage' is, however, an oversimplification... The really interesting thing is that phrase "the production ratio of U-235 to U-238 in a supernova is about 1.65"; the now-rare U-235 is actually more abundant than U-238 in the fresh debris of a supernova. Prolonged aging has preserved more U-238 (half life 4.47 billion years) than U-235 (half life 0.704 billion years) to the point that U-238 is now much more terrestrially abundant. If Earth had been formed with uranium that rich in U-235, there would have been Oklo events all over the place. Uranium wouldn't need isotopic enrichment to be used as fuel in light water reactors. Nuclear fission would probably have been discovered early in the 19th century, soon after the element itself was recognized, because any substantial quantity dissolved in aqueous solution would have reached criticality.

lazide 1y ago
It’s interesting to extrapolate that to the early earth - radioactive decay and fission interactions likely play a much larger role than we are able to reliably model. Okla is somewhat unique in that the formation survived for us to dig it up - most from that time would not.
cryptonector 1y ago
I read GP's question really as: "did all Uranium on Earth come from the same source?" and your answer implies "yes". I think that's right. The fact that everywhere we see the same U-235/U-238 ratio or very close (Oklo) strongly implies either a single source (supernova) or that if it was more than one source they were all at roughly the same time (6.5 billion years ago), with the latter seeming [to me] less likely, so a single source at 6.5 billion years ago is what makes sense. Unless there were many supernovae and their remnants mixed quite well in our corner of the galaxy where our sun was born.

mandevil 1y ago

This is just in our little corner of the Milky Way, but not thought to be the result of just one supernova. I last looked into this about a decade ago so I might be behind the times, but at that time the most popular theory was that the cloud that became our Solar System was the result of thousands of supernova scattering and mixing atoms, across both the first two generations of stars (the Sun is considered to be a third-generation star), and that mixing is thought to be an important factor in making it complex enough to have rocky inner planets, gaseous outer planets, etc.