Maybe the speed of light is irrelevant? Einstein wanted to make the speed of light the basic metric for the entire universe. That was because of it's consistency as a measured constant . Light has to be detected for the speed of light to be measured and that takes mater of variable forms across the electro magnetic spectrum. My discovery that photons actually don't transmit energy though space but are code as in messages being sent that have 'semantic' properties across the spectrum and periodic table and that light neither has properties of wave nor frequencies since those are properties of the material indicators from material detectors leads to all new conclusions. The first problem was trying to figure out where the subatomic angular momentum push comes from if no energy is transmitted by the photon though empty space. That led to the quick realization that momentum as all mater is in motion or relative motion due to the rest of the objects in the cosmos being in motion. Einstein thought that a person in free fall would not feel any sensation of falling as such and that is the same thing as being on a planet in a solar system in a galaxy all moving at more than 30 thousand meters per second relative to other objects out there in the universe.
Should our planet suddenly crash into any object just sitting still it would become as annihilated as all or part of the earth in that collision. We don't feel that energy or even know it exists. It is like sitting on top of a dam just before the dam breaks....just floating on a lake not knowing we have all that potential energy to go into a free fall. On a rocket ship the astronauts may not even realize they are in forward motion until they collide with something that makes a gaping hole in the space craft or totally blows it up in the collision. It is thus "dark energy", imperceptible except in the instance of a collision of some sort. That's momentum and at the subatomic level it may just be this invisible energy of momentum that photons release as they deliver their code to atoms and their subatomic particles on collision. So it thus says the speed of light is irrelevant. The coding sent in photons was meant for instantaneous communications between atoms or molecules where they originated not for deep space travel which is why they might as well be seen as instantaneous just distended possibly over billions of years. It is the interface of the detection mater where the photon is detected and the energy detected is most likely (it becomes more obviously the proof of it when you go on thinking about it) because of the dark energy of momentum which is what happens at the photon collision level. That says the interaction of code and energy is already part and parcel of the mater and not incoming from space as some component of a photon. My radiometer proof clearly shows photons can't have mass. I only recently discovered they also have no energy either. It is just a frame of reference error an illusion that we think photons transmit energy.
Momentum of objects in space is then obviously the basic metric and constant of photonic energy release. Almost everyone agrees that virtually everything in space is in motion. Does that mean that light or photons can slow down mater? Ah , yes to a very small degree. The idea of the force of light is actually the opposite. Moving on to astronomy we have ideas that we are observing a universe that is expanding and now one expanding and never slowing down. You can retest theories like that with the photon data to decide from a momentum perspective instead of the speed of light analogy. Much of mater we observe in the universe is at one with the universe by virtue that it is part of a system of momentum such as the earth sharing the basic momentum of the sun and the rest of the solar system. it promotes an order that prevents chaos of solar system objects crashing into each other very often. Things out of step with this momentum in the vicinity are a hazard to themselves and to the rest of the solar system. Not one with the universe. The next thing to think about with the dark energy of momentum is how it relates to nuclear physics as it just might and thinking of the dynamic collisions that might help lead to the right conditions that build heavy unstable radioactive atoms.