- #1
Lopes1801
- 1
- 0
This had me thinking for a while. Imagine a photon emitted by a very distant object at a redshift of z = 2.0 for example. As the photon travels through space, due to space expansion the photon's wavelength will shift towards red. With an increase in the wavelength there must come a decrease in the frequency. With that, the energy of the photon also decreases. Therefore, the photon must lose energy. And by the law of conservation of energy, this amount of energy cannot disappear. So where does the energy go to?
(I don't know whether the question should be labeled as Basic or Intermediary, so I arbitrarily chose one of the options)
(I don't know whether the question should be labeled as Basic or Intermediary, so I arbitrarily chose one of the options)