[spunkets]

They have at least 10% of the matter accounted for, so the 5% matter/45%dark are good rough numbers. The rest is vacuum, which is an important part of the universe. Each cm³ of vacuum contains more energy than the entire other 1/2 of the universe. The interaction of a photon with the vacuum is what limits light ot a speed of 3*10⁸ m/sec

[eastsider]

Each cm3 of vacuum contains more energy than the entire other 1/2 of the universe.

What kind of energy, and what is the source of that energy?