The mysterious dark energy is slowing the expansion of the universe. is believed to be the dominant form of energy in the universe. is attributed to the gravitational force of black holes. was suggested by the unexpected rotation speeds of galaxies

The dark matter is a dominant form of, energy often associated with black holes

Explanation:

Dark matter or dark energy constitutes about 85% of the universe and about a quarter of its energy density. Its ai called so as it does not tend to interact with observed electromagnetic radiation, such as light and thus invisible to the spectrum.  Gravitational lensing is a technique defined to prove the existence of the dark matter in the universe, in a black hole generally the entire star mass collapses and forms finite amounts of time. The evidence got from the rotational curves shows that dark matter in the center dominant position rotating galaxies like the spiral galaxies. Which the passage of time these galaxies speed of formation has slowed down and as galaxies spread and widen the rate of spread of dark matter also slows the rotation of galaxies.

South wales composes a lot of coal in that region.