Is dark matter, matter and energy at the same time?

In the the theory I propose, dark energy accelerates the flow of time, and dark matter (because it slows the expansion of the universe) would slow the flow of time. ... that most of the energy of the universe remains as E0 energy and that the amount of E0 energy of (empty) spacetime is not the same everywhere in the universe. read more

Only in the sense that all matter is matter and energy at the same time, via the usual energy/mass equivalence relation. (Not all energy is matter, but all matter has mass, and all mass is energy.) Addendum: Dark matter and dark energy have absolutely nothing to do with one another. read more

Unlike for dark matter, scientists have no plausible explanation for dark energy. According to one idea, dark energy is a fifth and previously unknown type of fundamental force called quintessence, which fills the universe like a fluid. read more

As Richard Muller suggests, dark energy accelerates the flow of time, and dark matter would slow the flow of time. This can be expected since mass of any sort slows time and light is relatively slower near a higher mass density. read more