Sun Emission Spectrum: Redshift/Blueshift & Visible Light

[Entangled]

Is the rather continuous spectrum of the Sun due to redshift/blueshift of the radiation emenating from the Sun? I understand that the emission spectrum of Hydrogen in the visible range is quantized to four discrete values, but I'm trying to understand how all frequencies of visible light are available for us to use.

 

[Bill_K]

Light is produced in many ways besides the excitation of individual atomic spectral lines. For example it can be produced when atoms collide. Quoting Wikipedia,

When the temperature of the body is greater than absolute zero, interatomic collisions cause the kinetic energy of the atoms or molecules to change. This results in charge-acceleration and/or dipole oscillation which produces electromagnetic radiation, and the wide spectrum of radiation reflects the wide spectrum of energies and accelerations that occur even at a single temperature.

 

[UltrafastPED]

The sun can be treated as a blackbody ... it is a very hot body, and thus emits radiation following the blackbody spectrum.

You can see definite lines in the solar spectrum; these are well explained here:
http://www.astro.washington.edu/courses/labs/clearinghouse/labs/Solarspec2/sunspec.html

 

[edguy99]

NIST data (http://www.nist.gov/pml/data/asd.cfm) give Solar Hydrogen Spectral Lines intensity in terms of energy: 250,000@12.09eV, 840,000@10.20eV, 90,000@2.86eV, 180,000@2.55, 500,000@1.89eV. The 1.89 eVolt energy is the most common one we can see.

We see all sorts of other photon energies that are generated since the hydrogen on the sun surface is moving around. If the hydrogen atom is moving away from us, we will see a photon with less than 1.89eV (red shifted), if moving towards us, it will have more than 1.89eV energy (blue shifted)

 

[Bill_K]

We see all sorts of other photon energies that are generated since the hydrogen on the sun surface is moving around. If the hydrogen atom is moving away from us, we will see a photon with less than 1.89eV (red shifted), if moving towards us, it will have more than 1.89eV energy (blue shifted)

No. As pointed out above, this is absolutely not the explanation. Doppler broadening of the spectral lines is present, but much too small to produce a continuous spectrum. And the majority of the photons are produced in other ways, simply from the thermal motion of the atoms.

 

[edguy99]

... much too small to produce a continuous spectrum. And the majority of the photons are produced in other ways, simply from the thermal motion of the atoms.

Thank you for the correction, I agree the thermal motion is the most important.