/sci/ - Science & Math

>>15943916
This is the sun's blackbody curve.

As I said before when any element absorbs a photon of light it absorbs it in a very specific wavelength of color and then emits it as a number of random colors in a random direction. This means it leaves gaps in the spectrum.

Because the sun is such a great blackbody radiation emitter all those gaps correspond to very specific elements in both the atmosphere of the sun and later in the atmosphere of the Earth. This is how we discovered helium, it corresponded to an absorption line we didn't know existed.
https://www.smithsonianmag.com/history/how-scientists-discovered-helium-first-alien-element-1868-180970057/

Everything in the atmosphere absorbs light at specifically known spectra. O2, O3, N2, CO2, H2O. Because most of the energy from the sun is in the visible spectrum and because most of those atmospheric compounds are invisible in visible spectrum that means sunlight passes right on through. Except for the O3 which absorbs the ultraviolet light.