ASTR 209 Lecture Notes - Lecture 7: Lyman Series, Balmer Series, Continuous Spectrum
30 Apr 2019
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If the gas wasn"t there i"d get a rainbow. Inside the gas thera are atomm in particular energy state: as long as i don"t have too many photos absorption line spectrum, opacity, opacity of a cloud is the degree to which the cloud intercepts radiation from behind. Photons are absorbed and re-emitted by the cloud. Important: opacity and emission go hand in hand: the observer detects more radiation if the layers are not completely opaque, what about the spectrum, apply this principle to one wavelengths at a time. Intensity of a layer has nothing to do with the distance: angualr size of the lamp depends on the distance, when different people in the room see the same lamp at different brightness level. If ;layer 2 is completely opaque there"s no layer 1: as long as opacity is high, i get most layer 1 and some layer 2. If the opacity is 0, you see layer two.
