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Photons from black body spectra

  1. Jul 23, 2011 #1
    I don't quite understand which are the fundamental processes for production of photons that are emitted by a "black body". Usually this is explained by considering a cavity in thermodynamic equilibrium but I am not interested in this. I am looking for a more practical description of this phenomena. I would for example like to know if this includes processes like light scattering, bremsstrahlung, cyclotron radiation,...
    For example the Sun spectra is known to be close to black body spectra. But how are the photons emitted by the Sun actually produced?

  2. jcsd
  3. Jul 23, 2011 #2
    Hello dgrosel:

    Here are a few sources of light (electromagnetic radiation) :

    Thermal (heat) radiation, fission and fusion reactions, an accelerating electron (I think), an alternating electric current, a moving magnetic field, maybe the Unruh effect (behind Hawking radiation) and more generally nuclear or electron energy transitions.

    In a nutshell, if a subatomic particle isn't in a ground state, it's often capable of emitting energy quanta...energy....electromagnetic radiation.

    But how are the photons emitted by the Sun actually produced?

    See this current related discussion:

    Where do photons come from...where do they go???? VERY difficult questions.
    In string theory, a piece of a string can be a photon.....if it has the right energy vibrational characteristics. In QM we have the Schrodinger (wave) and the equivalent Heisenberg matrix mechanics observational based descriptions.
    Last edited: Jul 23, 2011
  4. Jul 23, 2011 #3
    Hi Naty1,
    thanks for your reply.

    What I am interested in is actually only the so called "thermal radiation", since this is related to black body radiation. There should probably exist some elementary processes that contribute to this type of radiation.
  5. Jul 23, 2011 #4


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    "Most of the energy we receive from the Sun is the visible (white) light emitted from the photosphere. The photosphere is one of the coolest regions of the Sun (6000 K), so only a small fraction (0.1%) of the gas is ionized (in the plasma state). The photosphere is the densest part of the solar atmosphere, but is still tenuous compared to Earth's atmosphere (0.01% of the mass density of air at sea level). The photosphere looks somewhat boring at first glance: a disk with some dark spots. "

    Most matter not ionized, but some is. Therefore electrons find ionized atoms from time to time and get localized and give off photons? From time to time photons find matter and eject electrons and disappear.
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