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Oxygen in sun

  1. Oct 29, 2015 #1
    There is only 0.77% of oxygen in sun
    And only 0.29% of carbon
    The question is
    there is only small amount of o2 but how how sun is surrounded by fire with very less emissions of carbon
    ( referred to Wikipedia for amount of gas in sun)
     
  2. jcsd
  3. Oct 29, 2015 #2

    jfizzix

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    The sun is surrounded by fire in that it is surrounded by gas that's hot enough to be glowing red (which is as good a definition for fire as any). Some of it's even hot enough to be plasma, but that's not the point to be made here.

    Even though there's probably no significant amounts of chemical combustion going on, the nuclear fusion at the core certainly keeps the rest of the Sun hot enough to be the glowing ball of "fire" we see.
     
  4. Oct 30, 2015 #3

    davenn

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    its not fire in the sense of what is usually termed fire as the fire in a furnace or your home fireplace
    nothing is burning, there are NO flames. As you noted, O2 is almost non-existent

    The heat from the sun is primarily caused by the nuclear reactions occurring in its core.
    An interesting feature is the Suns corona which varies from 1 to 3 million Kelvin, very much hotter than the photosphere surface
    that is around 5800 K
    The jury is still out on all the causes for this, but the sun's magnetic fields do play a part.


    that is incorrect and quite misleading

    there is no combustion going on



    regards
    Dave
     
  5. Oct 30, 2015 #4
    Then how when objects get near catch up flame
     
  6. Oct 30, 2015 #5
    And what type of nuclear reaction takes place fission or fussion
     
  7. Oct 30, 2015 #6

    Drakkith

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    Get near what? The Sun?

    Fusion reactions occur in the Sun's core.

    https://en.wikipedia.org/wiki/Sun#Core
     
  8. Oct 30, 2015 #7

    davenn

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    what objects ?
     
  9. Oct 30, 2015 #8
    space ships or comets
     
  10. Oct 30, 2015 #9

    jfizzix

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    Okay, I'm here to learn as much as anyone else (mea culpa).

    Are you saying that fire is not red-hot gas,
    or that the Sun is not surrounded by gas?

    Not counting the corona (which doesn't produce most of the light we see anyway)
    the surface of the Sun's a mix of hot gas, and gas hot enough to become a plasma
    If you work out the Boltzmann statistics for hydrogen gas, at around 5800K, you'll find that most of the surface of the sun's in the gas phase, and not in the plasma phase.
     
  11. Oct 30, 2015 #10

    DrClaude

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    I don't know if this is what @davenn had in mind, but I would also not call it fire, as there is no combustion taking place.
     
  12. Oct 30, 2015 #11

    davenn

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    spaceships ? .... well don't think any made on earth have ever got close enough to the sun to worry about
    I cant find any specific info links, maybe others more informed than me can confirm my thoughts :smile: @DrClaude , @mfb

    spacecraft will be mainly metal and maybe some tanks of fuel and other than those fuel tanks exploding when the contents reaches ignition temperature
    all the remaining metallic parts would simply melt and vaporise

    The similar thing I suspect would happen to comets and meteoroids
    Comets are mainly lumps of rock dust and ice. The ices are going to vent from the comet, melt and vaporise
    Trapped pockets of ice and gasses could well cause lots of rock fracturing to occur, breaking sections of the comet apart
    but in the end, the rock or ice is going to melt and vaporise once the required temperatures are reached

    Regards
    Dave
     
  13. Oct 30, 2015 #12
    They don't, what has given you this idea?
    No comet or other object approaching the Sun will catch fire because there is no oxygen in space.
    They can get very hot though due to direct solar radiation, and comets have been seen to disintegrate.
    These basically melted and fell apart, they didn't catch fire in the normal use of the word 'fire' (=combustion).

    Also there are no flames around the sun, what you are seeing is electromagnetic radiation (light) which is generated by the fusion reactions in the Sun's core. (You can also directly feel infrared radiation from the Sun as heat on a clear hot day.)
     
    Last edited: Oct 30, 2015
  14. Oct 30, 2015 #13

    mfb

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    It is called plasma even if most atoms are neutral, as long as the ionized atoms and electrons dominate the behavior of the matter (and they certainly do that in the sun).
    They do not. They can melt and evaporate, depending on their chemical composition some chemical reactions might take place, but unless you carry around oxygen in the spacecraft (or comet) no combustion with oxygen happens.
     
  15. Oct 31, 2015 #14

    davenn

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    cool, so I covered it pretty well :smile:


    Dave
     
  16. Nov 1, 2015 #15

    jfizzix

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    I stand corrected
     
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