Early in the Universe’s evolution, most of the energy was carried by radiation. But radiation dilutes more quickly than matter so matter took over eventually as the largest energy contribution. Much later in the Universe’s evolution, dark energy—which never diluted whereas both radiation and matter did—came to dominate and now constitutes about 70 percent of the Universe’s energy density.
This would all be way, way clearer with a definition of energy.
And how was this dark energy able to keep the same density as the universe expanded?
· Flag
Brian
