Dark energy Definition and 553 Threads

What implications if any does the potential existence of dark energy have on the speed of light passing through empty spaces between galactic structures [remote space where dark energy is thought by some to dominate]? How might the permittivity and permeability constants be effected?

Dark Energy is now thought by some to contain 65% of the total mass of the universe. It will accelerate the expansion of the universe for some 20 million years. Then all normal matter/energy will have its constituents torn asunder resulting in a universe consisting entirely of Dark Energy...

this is not to argue or persuade but just to share a calculation. no answer needed unless you particularly like something about it. several websites, eg. NedWright's Cosmology tutorial have formulas for things like the critical density and the estimate that real density is very close to...