Redshift increases proportional to distance in all directions. The original assumption was that all expansion was an artifact of the original "bang" and gravity causes it to diminish at a steady rate.
Yet what Perlmutter, et al, discovered was the rate of expansion dropped off rapidly, then settled into a more steady rate. To use ballistics as an analogy, it was like the universe was shot out of a cannon, but after it slowed, an engine kicked in to sustain that more gradual rate. "Dark Energy" being the engine.
Now if we look at it from our point of view out, rather than postulating in from some initial stage, what we are seeing is a steady increase, that eventually goes parabolic.
Which, if redshift is an optical effect and not the entire universe blowing up, would be a basic compounding effect.
The most basic logical flaw with this cosmological model is that when they realized redshift does increase proportional to distance in all directions, it either meant we are at the exact center of the universe, or that redshift is an optical effect.
Given the only known cause at the time was some sort of medium the light was passing through, that would slow it. Aka, "tired light." Yet the light was otherwise undistorted, so it was dismissed.
Then it was decided, given the relativistic flexibility of "spacetime," that space itself must be expanding, therefore every point would appear as its own center.
What this brainstorm forgot is the central premise of General Relativity is the speed of light is always a CONSTANT, in every frame. So if space expands, the speed of light would have to increase, in order to remain Constant. Yet that would nullify it causing redshift.
So two metrics of space are being derived from the same light. One based on the speed and one based on the spectrum.
Consider the inchworm crawling on an expanding balloon analogy. Both of these are metrics.
In Ethan's animation, the waves stretch, but the speed doesn't increase.
Given it's the same light, which is the denominator and which is the numerator?
When the train moves down the tracks, it doesn't stretch the tracks, only increases the distance. So the tracks are the denominator and the distance is the numerator.
If the speed was the numerator, it would be a "tired light" theory, but as an "expanding space" theory, the speed is still the implicit denominator. The ruler used to measure space.
It has been shown that multi spectrum "packets" of light will redshift over distance, as the higher frequencies dissipate faster. Yet that would mean we are sampling a wave front, not observing individual photons that traveled billions of lightyears, which would cause much larger problems with current physics. That quantization is an artifact of measurement, not fundamental to the light.
