> Dark energy is really the fudge for all this. The idea is that creating new space takes energy. That has to come from somewhere and dark energy is our fudge f

> Dark energy is really the fudge for all this. The idea is that creating new space takes energy. That has to come from somewhere and dark energy is our fudge factor for that. No one really knows what dark energy is or looks like just like we don't know what creating new space looks like. It just solves a conservation problem. That's simply not true. You don't need energy to create new space (and you wouldn't magically get energy from nowhere if the universe were contracting). General relativity gives you expanding (or contracting) space just fine if dark energy doesn't exist -- in fact, that was the most common cosmological model before the late 1990s discovery that the expansion was accelerating. The fact that the simplest version of dark energy is the cosmological constant tells us your basic idea is wrong: if that energy was going into creating new space, then it would decrease over time, not remain constant. In fact, it's worse than that, because the cosmological constant is a constant energy density. So if expansion doubles some volume of intergalactic space, then the total amount of dark energy also doubles (while the total energy in the form of ordinary or dark matter stays the same, and the energy in the form of photons decreases due to redshifting). Conservation of energy in general relativity is messy and sometimes counter-intuitive; e.g. https://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html https://math.ucr.edu/home/baez/physics/Relativity/GR/energy_...