>Light is a particle. The particle does not degrade over time. Light is light. Or is it E=MC2 unless the light has travelled over a billion miles, then it E=MC?


E = mc^2 doesn't really apply to a photon (light particle) because it is supposed to have zero mass.

The energy of the photon is given by:

E = h * frequency

Where h is Planck's constant.

When the Universe expands, we observe it as Hubble's redshift which is a loss in frequency and energy proportional with distance.

These observations falsified our theories of space and light.

Which one had to give?

Space.

They could fix it by making space expand.

But I think that's the wrong move. The properties of light should be modified.

Einstein's theories replaced Newton's.

Newton's work very well, but it has limits to its accuracy.

Why should Einstein's be any different? Perfect with an unlimited domain?