Photons from black body spectra

In summary, the photons emitted from the Sun are a result of the photosphere being in a thermal equilibrium state.
  • #1
dgrosel
3
0
Hi,
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?

Thanks!
 
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  • #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:
https://www.physicsforums.com/showthread.php?p=3416597#post3416597

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.
 
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  • #3
Hi Naty1,
thanks for your reply.

Naty1 said:
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.

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.
 
  • #4
From:

http://www.windows2universe.org/sun/atmosphere/photosphere.html


"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.
 

1. What is a black body spectrum?

A black body spectrum is a theoretical model that describes the electromagnetic radiation emitted by a perfect black body. It is characterized by a continuous distribution of radiation across all wavelengths, with the peak intensity shifting to shorter wavelengths as the temperature of the black body increases.

2. How are photons related to black body spectra?

Photons are the individual particles of electromagnetic radiation that make up a black body spectrum. The energy of each photon is directly related to its wavelength, with shorter wavelengths corresponding to higher energy photons. The total number of photons emitted by a black body is determined by its temperature.

3. What is the significance of black body spectra in physics?

Black body spectra are important in physics because they provide a fundamental understanding of how objects emit and absorb radiation. They also serve as a standard for comparing the radiation emitted by different objects, and have practical applications in fields such as astrophysics and thermodynamics.

4. How do real objects differ from theoretical black bodies?

Real objects do not perfectly absorb and emit radiation like a black body does. They may reflect or transmit some of the radiation, which can affect the shape of their emission spectra. Additionally, the temperature of real objects may not be uniform, leading to variations in the emitted radiation across their surface.

5. How is the temperature of a black body related to its emission of photons?

The temperature of a black body is directly related to the amount and energy of photons it emits. As the temperature increases, the number of photons increases and the peak intensity shifts to shorter wavelengths. This relationship is described by the Planck's law, which is a key equation in understanding black body spectra.

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