After confirming dark matter, in 1998 astronomers discovered that the expansion of universe, previously thought to be slowing down under the force of gravity, was actually accelerating. Some sort of negative gravity had to be pushing the universe apart against the gravity that pulls it together. The force stopping gravity from collapsing the universe was called dark energy. Cosmologists estimate that dark energy is 68% of the energy of the universe, dark matter is 27% and the standard model’s particle matter is at best only 5%. Since the standard model’s particles only account for a tiny fraction of the energy of the universe, it isn’t even close to being a theory of everything.
Dark energy is a weak effect, spread evenly through space that seems to have changed little over time. In equations, it makes space flat so some call it a property of space itself but if so, it should increase as space expands. If it is caused by particles, as the standard model assumes every force is, it should weaken over time as space expands but it doesn’t. Particles of any sort should clump together not remain evenly spread and what particle could cancel gravity to push the universe apart? The standard model can’t explain dark energy at all because a particle can’t have a negative energy.
In quantum realism, our space is the inner surface of a bubble expanding into a quantum bulk so an expanding universe must lose energy, just as expanding a box cools the gas within it. New points of space are added all the time throughout space and since they are new, for their first cycle they receive but don’t transmit energy. This negative energy effect, spread over all space, is then dark energy. It does not diminish as space expands because more of it continually pops into existence to keep pace with the expanding universe and indeed it may be gradually increasing.
If dark energy comes from new space, no particle cause will ever explain it.