What science knows on the "dark energy"?

Question

Which its nature.. It is of electromagnetic origin?

Answer 1

To be frank, at the present time, not a lot.

Answer 2

The idea of dark energy was hidden in Einstein 's Cosmological constant which had been erroneously discarted for nearly a century has presently come into being as Real.
Dark Energy has been realized that it exists as per Einstein's cosmolocical constant and field equation.

The proof came about when observation was made on the recession velocity of th e Galaxies of this Universe.

And since mass is defined as the quotient of energy and velocity squared, Dark matter was postulated to exist ,and is basically the Antimatter that has been observed in the micromases of the Atoms.
The assumption about electromagnetic nature dark energy iwould be the same for both the magnetic phenomena and the electric phenomena and the gravity phenomea as being the result of the same mechanism of the function of the Universe.

This is the Unificationon force that Einstein had in his Equation and never really realized it .
That means there exists a Unification of Energy, Force and Power in the Substance of Space in the volume of the Universe that was at one time called the AETHER.

Answer 3

Dark energy is coming...This a fascinating subject.

New evidence has confirmed that the expansion of the universe is accelerating under the influence of a gravitationally repulsive form of energy that makes up two-thirds of the cosmos [1]

See references below

Answer 4

"universe from nothing" theory says that out of nothing matter came. Since matter cannot come from nothing, so came anti-matter. By chance if matter meets anti-matter, gamma rays seem to come out. But since universe does not have free gamma radiation, no concrete existence of dark energy is proved.