4 ms·

Not age of the star but experiance of the material that formed the star, how many past stars was it baked in. There may be some pocket of virgin bigbang hydrog

Not age of the star but experiance of the material that formed the star, how many past stars was it baked in. There may be some pocket of virgin bigbang hydrogen out there that could theoretically form a new low-metal star. A low-metal/high-mass star could be a technosignature of a very advanced civilization. Nobody would dare mess with anyone capable of building themselves a new star out of only hydrogen: the ultimate keep off my lawn sign.

LeonB 3y ago
If I were* the median atom in the universe, how many times would I have been through a full star cycle? 0? 1? 3000? * I’m not, but I’m just saying, “If I were” (but I’m not)
- anon25783 3y ago
  Zero. Of all the atoms in the Universe, about 98% are primordial hydrogen and helium[1], "primordial" meaning they formed very shortly after the Big Bang. [1] https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem...
  - simonh 3y ago
    That’s not quite the same question. Most of the primordial hydrogen that goes through stars isn’t fused into anything else and therefore is still primordial hydrogen, but it has been in one or more stars.
    - LeonB 3y ago
      Who’s to say it hasn’t been through a dozen stars? Or a thousand? It could’ve blinked into existence five minutes ago. (I could be wrong)
    - anon25783 3y ago
      Hmm... I wonder what portion of all matter in the Universe is the intergalactic medium? I would conjecture that most matter in the intergalactic medium has never been inside a star.
- throwup238 3y ago
  Most of the universe is primordial atoms that haven’t fused yet but if you were to take an iron atom, it probably would have been through only one star cycle. A main sequence star at least ten times the size of the sun goes through several stages as it ages: hydrogen, helium, carbon, neon, oxygen, and finally silicon burning. The silicon burning stage produces abundant iron and the type II supernova that follows spreads it around.
idiotsecant 3y ago
Such a civilization wouldn't have much incentive to build 'keep off my lawn' signs, I don't think, given that the answer to such an advertisement should be a trillion relativistic snowflakes aimed at every system within a thousand lightyears. Anyone observing such a show of power would have no choice but to act first before that civilization did it to them.

LeonB 3y ago

If I were* the median atom in the universe, how many times would I have been through a full star cycle? 0? 1? 3000? * I’m not, but I’m just saying, “If I were” (but I’m not)

anon25783 3y ago
Zero. Of all the atoms in the Universe, about 98% are primordial hydrogen and helium[1], "primordial" meaning they formed very shortly after the Big Bang. [1] https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem...
- simonh 3y ago
  That’s not quite the same question. Most of the primordial hydrogen that goes through stars isn’t fused into anything else and therefore is still primordial hydrogen, but it has been in one or more stars.
  - LeonB 3y ago
    Who’s to say it hasn’t been through a dozen stars? Or a thousand? It could’ve blinked into existence five minutes ago. (I could be wrong)
  - anon25783 3y ago
    Hmm... I wonder what portion of all matter in the Universe is the intergalactic medium? I would conjecture that most matter in the intergalactic medium has never been inside a star.
throwup238 3y ago
Most of the universe is primordial atoms that haven’t fused yet but if you were to take an iron atom, it probably would have been through only one star cycle. A main sequence star at least ten times the size of the sun goes through several stages as it ages: hydrogen, helium, carbon, neon, oxygen, and finally silicon burning. The silicon burning stage produces abundant iron and the type II supernova that follows spreads it around.

idiotsecant 3y ago

Such a civilization wouldn't have much incentive to build 'keep off my lawn' signs, I don't think, given that the answer to such an advertisement should be a trillion relativistic snowflakes aimed at every system within a thousand lightyears. Anyone observing such a show of power would have no choice but to act first before that civilization did it to them.