I heard in a documentary that the elements of the sun can be read out from the absorption lines.
But I have also heard that an elements absorption lines and emission lies coincide. That means the sun can emit only the colors that its elements absorb.
So if that is the case where does all the other colors (which are not in the absorption spectra) of the sunlight come from?
And why aren't they being absorbed?
Thanks a lot.
Best Answer
A stars emission comes from thermal radiation, which will approximately be equal to black body radiation. However part of this spectrum will be absorbed by the outer layers of this star. It is true that absorption lines and emission lies coincide, so these frequencies will be re-emitted. But they are scattered in all directions, so also back into the star. So the further you move up in the outer layer, the more of these frequencies are "reflected" back into the star.