5 ms·

Blood is red due to iron content. Iron can only be produced by nuclear fusion in stars. We are all stardust.

• JumpCrisscross 10mo ago
  > stardust What form does stellar iron take once the star it was formed in fails? Is it a gas? Small solids? Individual atoms?
  • chasil 10mo ago
    As I understand it, much comes out as nickel-56 that undergoes radioactive decay to iron-56 in short order. It is also somewhat ionized.
  • A_D_E_P_T 10mo ago
    A hot, expanding, fully ionized plasma. Over weeks to years it cools, recombines into ions/neutral atoms, forms molecules in some regions, and a fraction condenses into dust grains, often as iron-bearing compounds like FeS and as inclusions in silicates.
    • JumpCrisscross 10mo ago
      > Over weeks to years it cools Neat. Good source for reading up more on this? > a fraction condenses into dust grains Does it deposit straight into grains from gas? Or is there a period when a bunch of liquid iron is sitting around radiating its tail off?
      • chasil 10mo ago
        I don't think liquid can exist in space. If I remember from undergrad thermodynamics, the vapor dome describes states where liquid can exist, and (gas) pressure must be present. https://www.sciencefocus.com/space/strange-reason-space-wont-let-liquids-exist https://www.sciencefocus.com/space/strange-reason-space-wont...
        • JumpCrisscross 10mo ago
          > don't think liquid can exist in space Ordinarily, no. Whether supernova remnants count as “space” might be an alternate phrasing of my question.
          • mr_toad 10mo ago
            Even before it exploded it would have been less dense than water. It just goes from a hot cloud of gas to a cold one.
            • chasil 10mo ago
              As I understand it, a white dwarf is "electron degenerate matter," which is more dense. https://en.wikipedia.org/wiki/Degenerate_matter https://en.wikipedia.org/wiki/Degenerate_matter
      • A_D_E_P_T 10mo ago
        Here you go bro: https://orca.cardiff.ac.uk/id/eprint/110293/1/10.1007%252Fs11214-018-0492-7.pdf https://orca.cardiff.ac.uk/id/eprint/110293/1/10.1007%252Fs1...
        • JumpCrisscross 10mo ago
          :D Thank you!
      • pixl97 10mo ago
        > liquid iron is sitting around radiating its tail off With the energy imparted by the cataclysmic devastation of a supernova I'd assume it's a plasma that cools and sublimates into a gas. These clouds of gas typically have magnetic fields that can bring particles close together where they form dust/grains.
• stouset 10mo ago
  I feel like iron in the blood gets a lot of airtime, but literally all the carbon in our bodies is star stuff too. As is the oxygen making up the water. And almost everything else.
  • chasil 10mo ago
    The CNO cycle dominates fusion in stars much larger than our own. The carbon transitions to nitrogen and oxygen repeatedly. https://en.wikipedia.org/wiki/CNO_cycle https://en.wikipedia.org/wiki/CNO_cycle
    • gus_massa 10mo ago
      From your link: > This result therefore paves the way towards a direct measurement of the solar metallicity using CNO neutrinos. Our findings quantify the relative contribution of CNO fusion in the Sun to be of the order of 1 per cent; I find it amazing that we can analize the composition of the core of the Sun measuring the energy of the neutrinos. (Photons are not useful, because they bounce a lot of times before escaping from the Sun, so they provide only information about the outher layers.)
• fluoridation 10mo ago
  The color of feces is also due (partly) to the iron content of blood. Stars are fecal particles that haven't been shat out yet.
• bossyTeacher 10mo ago
  > We are all stardust. Is that meant to be good? I always chuckle when people make these kind of statements. Is the association to cosmic objects meant to make you feel better about something? I personally don't find stardust particularly interesting. The fundamental forces of nature on the other hand are much more appealing to me.
  • pgalvin 10mo ago
    I believe it’s quite common for people to marvel at the vastness of the universe. For that reason, people might like the tangible link that they feel to the rest of the universe when they think of this - it’s amazing to think of how small we are in it, but also amazing to think of where “we” came from.