Let's say we run a light source (a strong torch) with full spectrum light through a big, transparent, glass box filled with neon. Will we be able to see any Fraunhofer lines on the spectral analysis of the light leaving the box? Will the neon gas trapped in the box absorb characteristic frequencies and heat up? Or does this only work in stars?

By the same token, will doing a spectral analysis on the direct sunlight give us different results than doing it on the sunlight passing through a block of glass itself? Would we be able to tell the chemical composition of this piece of glass just by looking at the Fraunhofer lines?


Spectroscopy is used on solids to determine some of its properties, but it can be used on gas as well.

The experiment (for UV light, using H, He, Ne and Ar) was done in 1941 by Takamine and Tanaka, and written up in Astrophysical Journal, vol. 93, p.386 (DOI 10.1086/144275). You can find the write up at this link

Quoting just a short section:

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Interestingly, they find that as the pressure of the gas increases, the lines quickly blur (the time between collisions becomes short to the point where it affects the resonance of the individual lines).

If the sunlight you are studying has passed through a piece of glass, that will affect the results. This is why people usually use a differential device - in one arm they have the optical windows and the sample, and in the other arm they have just the windows. The difference in signal between the two arms is due to the sample alone - properties of the windows cancel out.

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