Astronomy - Ch. 5: Light & E&M Radiation (21 of 30) Emission Spectrum of Nebula

In this video I will explain why nebula have emission spectra when they are not very hot.

[ALAL-jmlr]

Hi, is there any theory or explaination why different atoms have specific different spectrum?
Does this means every atoms electrons have only allowed levels to jumps between? And not allowed to make all possible jumps between all known levels?

[manuelcheta]

So that means that every element has a fixed number of lines in the emission spectrum or can they vary in number?

[glennedwards]

Michel, thanks for the time and energy put into these videos!  They're fantastic. 
One question regarding this process:  Does this mean that the electrons being kicked into the higher orbits and falling back down all take place at the speed of light...since we can observe this phenomena instantaneously?  It seems like it should be less since it's really a process of moving up and then back down....if both events (moving up and back down) took place at the exact same time (the speed of light) wouldn't that mean that the electron would be moving either up or down (or both) faster than the speed of light violating Einstein's universal speed limit?  Sorry, this question became longer than I anticipated as I thought about it. :)

[LearnMechanicalinதமிழ்]

Sir if we give a high energy and the electron is now knocked out, then will hydrogen become unstable?

[sushaminirastogi]

Thank you sir from my heart. 🙏🙏🙏🙏 from INDIA

[harshannn]

Sir but they have negative signs
(-13.6)-(-3.4)= -10.2
It's -10.2 bcuz energy is releasing it's exothermic..
Sir is it right

[lifetheuniverse]

If I understand this properly... here is a table of eV differences for all N 1 - 14