Cosmic chemistry

Discussion in 'The Off Topic Room' started by Nemo, Dec 7, 2018.

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  1. Dec 7, 2018 #1

    Nemo

    Nemo

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    Started this to continue a fascinating conversation about the origin of various elements and to save another thread from derail:

    The story so far:
    Most of the heavier elements come from a few supermassive stars (for elements up to iron) or from supernovae (for elements heavier than iron, which is the highest entropy state of matter).

    One member asserted (perhaps in jest) that this is all an unprovable science based fairy tale.

    A periodic table was presented showing the origin of each element ( @Vils -could that be reposted here?) which shows that the story is a little more complicated again.

    What is a white dwarf? A neutron star?

    How big is a massive star?

    What causes a supernova?
     
    Last edited: Dec 7, 2018
  2. Dec 7, 2018 #2

    inferno

    inferno

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    on a side not. I've heard that even when the long cold death of the universe occurs not all matter will be iron. much of it will be cobalt and nickel. not all of it will have time to convert to iron (or is it transmutate??) or just decay?
     
  3. Dec 7, 2018 #3

    Vils

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    Ok [​IMG]
     
  4. Dec 7, 2018 #4

    MontezumaBoy

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  5. Dec 8, 2018 #5

    Xenif

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    Im not an astrophysicist by trade so if my awnsers piss off any astrophysicists I apologize ahead of time.

    1) white dwarfs are stellar remnants of low-medium mass stars. The left over core once the star is no longer able to fuse the remaining element (which is carbon and oxygen), these things are small (planet size) and cannot exceed 1.44 solar masses (if it does eletro-degenerate force loses to gravity and you probably get a supernova)
    A neutronstar is when a massive (10-30solar masses) star goes supernova but the the core gets compressed even more than a white dwarf,but not enough to form a blackhole. Basically its a sphere about (in theory) 30km-ish across, and the whole thing has the same density as an atomic nucleus. If mass exceeds 3solar masses, neutron-degernerate pressure loses to gravity and you get supernova and a spanking new black hole.
    Hope that answers some questions. Knives are far more complicated than stars.
     
  6. Dec 8, 2018 #6

    Nemo

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    Good answers... thx.

    A neutron star having the same density as an atomic nucleus is amazing.
     
  7. Dec 8, 2018 #7

    Kippington

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    Imagine seeing something that massive, so dense in fact that dropping a small everyday object (such as a banana) down into it would be enough to tip it over the edge, causing a collapse into a black hole.
    That would be an "OH SHI..." moment and a half! :eek:
     
  8. Dec 8, 2018 #8

    Nemo

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    Nope. I wouldn't use a banana. I'd drop in a really sharp knife...
     
  9. Dec 15, 2018 #9

    MindTone

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    Hmm, knife-related star dream! How about a knife forged from neutronium? :rolleyes: (the stuff neutron stars are made of)
     
  10. Dec 17, 2018 #10

    Marek07

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    Dream? :confused:
    A knife forged from a substance that (probably) exists for only a few seconds as a star is dying. And with density around 4 x 10¹⁷ kg/m³ who's going to make a knife, pick it up and then cut something (an atom perhaps?) all in the last couple of seconds of their existence? Assuming existence is a thing on a star, dying or otherwise. We often talk of unicorns here. This idea is waaaaaaay beyond that!
     
  11. Dec 17, 2018 #11

    Xenif

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    Density of 4 x 10^17 only if you have enough gravity to hold them together, otherwise at room temp/regular pressure it's many times less dense than even hydrogen. So technically if a knife was to made it can only be on the surface of a neutron star, which with gravity accounted for it would probably weight on ... 100+million tons
     

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