Many thanks again,
Am I right in thinking the tired light theory failed in part due to red and blue doppler shifts from the rotating arms of spiral galaxies?
I understand that the measured speed of light in a vacuum is constant regardless of the motion of source or observer. However a medium...
Follow up question
Many thanks for the replies.
I am puzzled by frequency shift which I think relates to change in energy of a photon -however the doppler effect is normally explained as a frequency change in the light wave(not the energy of a particle). Intuitively I would expect photons to...
Light from distant stars is doppler shifted. Is the measured speed of light from these stars lower than the speed of light from the sun? Would one expect the permativitity of free space to vary over the universe?