The reality is that the James Webb will do to the Big Bang Theory, what CERN did to supersymmetry and string theory.
What they will see is that background radiation is the light of ever further sources, shifted off the visible spectrum. Basically the solution to Olber's Paradox; The light of infinite sources.
The expanding universe model is based on the apparent fact the only way for light to redshift is recession of the source. Though some filter could interfere with the light, aka, "tired light." Yet it's too clear for any evident interference.
Originally it was assumed these distant galaxies are simply moving away in space, but as observations soon showed, the over-all redshift increases proportional to distance in all directions. So, either we are at the exact center of the universe, or it is an optical effect.
Then it was decided space itself must be expanding, because "spacetime," in what will go down in history as science's greatest brain fart.
For one thing, if space is expanding relativistically, then the speed of light would have to increase, in order to remain CONSTANT!!!!
Yet that would negate explaining redshift, but whatever.
As it is, light is being treated as some wavy line on the surface of space, that becomes less wavy, as the space stretches. Really, that's the idea. Consider the inchworm crawling on an expanding balloon model.
For one thing, two metrics of space are being derived from the same intergalactic light. One based on the speed and one based on the spectrum. One the inchworm and one the balloon.
(Actual physicists understand waves are generated by the motion of the energy through a medium and while there is no aether, the waves are only observed by interaction with the measuring device. Energy is not necessarily synonymous with the information derived from it. Processes generate patterns. The physics generates the math. Map versus territory.)
In this model, the speed is Still being treated as the denominator, or it would be some form of tired light theory. Just go back through this article and see how distances are always expressed in the speed of light, aka, lightyears.
That means the expansion is the numerator and as anyone with an elementary math education, or at least one from a few decades ago, knows, that means it is increasing distance, in stable space, not "expanding" space. So we are back to classic doppler shift and the "center of the universe, or optical effect"problem.
There is one way light will redshift over distance and that is as "packets," as the higher frequencies dissipate faster.
The much larger Pandora's Box this creates, is it means we are sampling a wave front, not observing individual photons, traveling billions of lightyears, so that the quantization of light is a consequence of its absorption and measurement, not fundamental to light itself. Energy versus information. That means reality is a mix of analog and digital, not strictly digital.
Like life, some choices are binary and some are a spectrum. Nodes and networks, particles and fields.
As this effect apparently compounds on itself, that is why the rate of redshift goes parabolic, from our point of view outward, so there is no need to postulate Dark Energy, to explain the latter part of the curve, not attributable to the initial impulse of the Bang.
The winds of change will howl through the multiverse.
