If the light loses energy, then it must surely lose it to something? And if your last point that energy isn’t being conserved in our universe, in which case we are either in some deep shit with the first law of thermodynamics, or our universe isn’t an isolated system.
The thing about photons is that they redshift, losing energy as space expands. If we keep track of a certain fixed number of photons, the number stays constant while the energy per photon decreases, so the total energy decreases.
The energy is actually not conserved across the universe in general relativity, as it is currently understood. Conversation of energy is due to the time symmetry, which the expansion of space breaks.
If the light loses energy, then it must surely lose it to something? And if your last point that energy isn’t being conserved in our universe, in which case we are either in some deep shit with the first law of thermodynamics, or our universe isn’t an isolated system.
Seems energy is not conserved.
https://www.preposterousuniverse.com/blog/2010/02/22/energy-is-not-conserved/
The energy is actually not conserved across the universe in general relativity, as it is currently understood. Conversation of energy is due to the time symmetry, which the expansion of space breaks.