One way to explain various cosmological features would be if the universe is infinitely old. Currently we have a cosmological model that assumes the entire universe can only be about 13.8 billion years old. Yet as science, it can’t be falsified, because every time there is a gap between prediction and observation, some enormous new force of nature is assumed and all is fine.

Before Inflation, Dark Matter and Dark Energy, the original patch was when they realized redshift increases proportional to distance in all directions. Meaning that we appear to be at the center of this expansion.

So it was changed from an expansion in space, to an expansion of space, because Spacetime!

Which totally ignores the central premise of General Relativity; That the speed of light is measured as a Constant in every frame. If intergalactic light is being redshifted, obviously it cannot be Constant to intergalactic space/distance! Necessarily there would be more lightyears, not that the lightyears are being stretched.

Two metrics are being derived from the same light. One based on its spectrum and one based on its speed. Given the expansion is relative to the speed, causing the redshift, the speed is implicitly still being treated as the real “ruler.”

We are at the center of our point of view, so an optical explanation for redshift might be worth considering. “Packets” of light do redshift over distance, as the higher spectrums dissipate faster, but that would mean we are sampling a wave front, not individual photons traveling billions of lightyears.

Which would suggest photons are not indivisible and that opens a significant can of worms for quantum theory.

I suspect the problems besetting theoretical physics will not be solved with more math, as strings, multiverses, etc, but reviewing some of the unquestioned assumptions.

Epicycles were brilliant math, as a modeling of our point of view of the cosmos, but lousy physics. Not because every detail hadn’t been worked out, but because certain assumptions were wrong.