Dark Energy from Lost Light
What happens to the light that shines out from stars but does not hit anything, light beams that keep going off into the black edges of the universe? If the light never hits anything it gives no evidence of its existence, a beam that hits nothing is identical to no beam. Energy was used in its generation but instinct tells me that only the act of detecting the light would cause it to be, and that light that is never detected and never encounters any object does not exist because it is identical in every way to no light. The definition of this "lost light" is that it is not ever and cannot be detected.
Could this lost light return its energy somehow and become what we know as dark energy? How much light from stars is destined to encounter nothing? There are not many stars and planets for a beam to hit but space dust and thin gasses might provide a target for a measurable proportion of the light emitted by all stars to hit. As atoms are tiny perhaps a huge proportion of light is destined to miss all of the atoms in the universe.
Perhaps the amount of lost light is the same as the amount of "dark energy", the name for energy that accelerates the expansion of the universe. If my instinct above was correct then the energy used to generate lost light might not be expelled in a beam that is fundamentally undetectable but instead used to provide some motive force or gravitation. How ironically named it would be if dark energy was made by light!