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Re:star crust 10 billon times stronger than steel

  1. May 6, 2010 #1
    Just out of curiousity, regardless that we cant reach it, can a star like that be mined? would it still retain its strength?
     
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  3. May 7, 2010 #2

    Matterwave

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    Re: star crust 10 billon times stronger than steel

    A star is not made of solid material...it's a huge ball of gas/plasma basically.
     
  4. May 7, 2010 #3

    mgb_phys

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    Re: star crust 10 billon times stronger than steel

    I'm guessing the OP is thinking of a neutron star - that's the only thing i can think of with a 'crust'.
    But no - it's only a crust because of the conditions on the star, if you removed it - the neutrons would just form into a ball.
     
  5. May 7, 2010 #4

    Chronos

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    Re: star crust 10 billon times stronger than steel

    Neutron stars are believed to have an iron crust. The reasons are fairly complicated. Mining them would be impractical. If you somehow managed to remove a hunk, it would evaporate once you pulled it away. The intense gravity of the neutron star is all that holds that stuff together.
     
  6. May 17, 2010 #5

    Entropee

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    Re: star crust 10 billon times stronger than steel

    Even if you were to mine something from a neutron star, when you got it back to earth (assuming it was a significant amount) it would be way too massive to use for anything.
     
  7. May 18, 2010 #6

    Mentallic

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    Re: star crust 10 billon times stronger than steel

    Could you please explain this in more depth? Why would the iron evaporate and would the neutron material evaporate also?
     
  8. May 18, 2010 #7

    Janus

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    Re: star crust 10 billon times stronger than steel

    Essentially it is like a extremely compressed spring and it is the intense gravity that keeps its compressed. Once that gravity is removed, all that energy stored by the compression is released, and it is enough to evaporate the iron.

    As far as the neutronium is concerned, neutrons, on there own, are unstable particles with a half life of about 15 min. Again, it is the intense gravity that prevents them from decaying into a proton, electron and an electron-antineutrino. Remove the gravity and the mass will begin to decay.
     
  9. May 18, 2010 #8

    Mentallic

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    Re: star crust 10 billon times stronger than steel

    Very interesting, thanks :smile:
     
  10. May 18, 2010 #9
    Re: star crust 10 billon times stronger than steel

    It's kind of sad that we can't synthesize materials that strong another way. Isn't there some kind of ceiling that physics puts on the strength of materials under Earth conditions?
     
  11. May 18, 2010 #10

    russ_watters

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    Re: star crust 10 billon times stronger than steel

    I'm wondering if the word "strong" really should apply since this material exists in an environment where chemical bonds aren't possible.
     
  12. May 19, 2010 #11

    Entropee

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    Re: star crust 10 billon times stronger than steel

    Good point Russ...
     
  13. May 21, 2010 #12
    Re: star crust 10 billon times stronger than steel

    If were talking about the crust of a neutron star then it should typically still be electron degenerate. The outer crust would be heavy nuclei (Fe56 --> Ni62 --> Kr118) and electrons while the inner crust would be neutron rich nuclei with a superfluid of neutrons and electrons but still the pressure would be from electron degeneracy. This crust would be a little over a km deep and the density would range from 1e+9 to 2e+17 kg/m3 (or 1 to 2e+8 tonnes/cm3, the size of a sugar cube). http://var.astro.cz/brno/perseus4_2002_clanek2.pdf" [Broken] page 2.

    In regard of neutron degenerate matter, as already stated, if you take neutron degenerate matter out of the gravity field, it will fly apart, but there is a prediction for some quark stars (or strange stars) that strange quark matter might be stable-

    '..When comparing the energy per baryon of Fe56 and nuclear matter with the energy per baryon of 2-flavour (u,d quarks) and 3-flavour (u,d,s quarks) strange matter, theoretically the energy per baryon of strange quark matter may be below 930 MeV, which would render such matter more stable than nuclear matter. Fe56 ~930 MeV, 2-flavour quark matter ~1250 MeV, 3-flavour quark matter ~830 MeV...'
    http://arxiv.org/PS_cache/astro-ph/pdf/0407/0407155v2.pdf page 19, fig. 11
     
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