A Ha: "What book says this? I've never read a cosmology or physics book that said new energy was coming into the universe. Energy in the universe is balanced, and no new energy is being added. If it were, it would be all over the news.
Currently reading Sean Carroll " from eternity to here" and he, quoting old sources, explains, how dark energy is an inherent property of space, and the added space of the expanding universe increases the energy content of the universe. This explains the accelerated expansion of the universe, that normally would experience a gradual slow down, if the energy content of the universe were constant. that dark energy is thought to be a possible feature of the pre-beginning condition too. or?