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I The cold interior of the Sun seen in a sun spot

  1. Jul 8, 2016 #1
    The sun we see has a measured surface temperature of 5800K. This is the temperature of the photosphere , a glowing layer of plasma radiating energy from the sun.

    But when there is a hole in this layer and we look deeper into the interior the temperature drops to 3800K.
    How can this possibly be explained?

  2. jcsd
  3. Jul 8, 2016 #2


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    To quote wikipedia's article on sunspots: They are areas of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection.

    Heat is lost from the region in the form of EM radiation, but the lack of convection means that there is no heat transfer from the inside to replace the lost heat. Hence the entire region cools down. Eventually the magnetic field flux breaks down, convection resumes, and the sunspot disappears.
  4. Jul 9, 2016 #3


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    Or, in other words, the sunspot is not a hole in the photosphere as assumed by the OP.
  5. Jul 9, 2016 #4


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    A sunspot is merely a place where solar magnetic field lines converge and impede radiant emissions from the sun - a cool oasis in other words. This phenomenon has been detected on other stars, so its not really considered peculiar.
  6. Jul 9, 2016 #5
    Thanks for the replies......I get it!
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