When an electron emits a photon from changing energy levels, the frequency of the photon depends on the difference between the energy levels.
But if someone is moving with respect to the atom, the frequency will be apparently red shifted or blue shifted.
Does this mean that the energy levels of the orbits of the atom look to have different values if you are moving with respect to them? But, the apparent energy difference can be different depending on whether the photon is emitted towards you or away from you.
What's going on? Aren't energy levels of orbits supposed to be a fixed value given the kind of atom?