Hi thanks for the response. I'm so confused because my teacher said you can't have an absorption spectrum without an emission spectrum? So when a continuous spectrum is sent through a say gas cloud in space, it will absorb and also emit in different directions. I suppose what I'm asking is when using atomic absorption spectroscopy, do scientists still rely on absorption and emission, or have they found a way to only extract absorption? For example, in that example you mentioned, or in the link below, they say this is how you analyse absorption spectrums. What I'm asking is, in this scientific setting, do the absorption spectrums still give off emission spectrums? Or do they cool the gas so it doesn't give off an emission spectrum, but they still get the absorption spectrum?
(https://easychem.com.au/monitoring-and-management/manufactured-products/atomic-absorption-spectroscopy-aas/)
Oops...I totally didn't forget about this
What your teacher says is right, for the spectrum to be termed an "absorption spectrum", there must be some missing wavelengths which have been absorbed by the gas cloud; these wavelengths WILL be emitted elsewhere.
Important point to note here: you won't be measuring an emission spectrum from something like the sun's radiation or passing incandescent white light through an unexcited gas...the wavelengths which have been absorbed will be re-emitted in random directions. It's more feasible to measure the wavelengths that pass through the gas and create the absorption spectrum. From this, you can generate an emission spectrum with the missing wavelengths. You can then use this emission spectrum to identify the gases that the light was passed through, e.g. the gases that make up the sun.
The only instance (at least, the only one I'm aware of) where you would be directly finding emission spectra is with the spectral analysis of light emitted from a low-pressure gas discharge tube, excited by a high voltage. This is because the spectral lines that show up on the emission spectrum are not as a result of the gaseous atoms re-emitting photons that it absorbed from an incandescent light source...they are from the electrons of the gaseous atoms being excited by the electrical energy and then releasing this energy as photons of light when they fall back to their stable ground state. The emission spectrum that is created by exciting low-pressure gas in a discharge tube with a high voltage is unique to the gaseous element in the tube, e.g. neon, hydrogen, etc. Using these unique elemental 'signatures', scientists (us too) can then identify the gas element(s) that, for example, make up the sun or is present in a discharge tube, etc.
I hope I've answered your questions. If not, fire some more