WHAT IS DARK ENERGY?
The definition of dark energy is still not precise and known properly. All that the scientists know about this dark energy is, it is an unknown source of energy and they don’t know where exactly it is originated. It is still being guessed or hypothesized to saturate all the space and lead to accelerating the explosions taking place. It is a well-accepted hypothesis that dark energy is including in the expansion of the universe at the very fast rate. It is a repulsive force and it acts opposite to gravitational force. Like dark matter, dark energy cannot be directly observed. Dark energy takes up 72% of the entire mass-energy density of the universe. Whereas, dark matter takes 23% and normal matter 5% of this universe.
In 1998, two separate teams of astronomers found out that due to some supernova the expansion of the universe was explained. These both teams announced that the universe is going through an expansion phase. That phase is accelerated expansion phase by this dark energy. Unlike dark matter, there are no scientific explanations for dark energy. According to a recent idea, the fifth and previously unknown type of fundamental force called quintessence, which fills the universe like a fluid. According to Einstein, the constant of dark energy would be a repulsive force which is keeping the universe from collapsing on itself. And further on Einstein gave an idea when the astronomical observations revealed that the universe was expanding, calling the cosmological constant as his biggest blunder ever. The cosmologists calculate how the universe has grown and took a shape over the past thirteen point eight billion years. All the theories together explain all-natural phenomena in the universe, these theories are none other than general relativity and quantum mechanics.
According to quantum mechanics, vacuum energy would have a great large amount of energy density to it. But if that thing turns true, then the general relativity says that this particular dark energy would have an incredibly strong gravitational effect. Substitutes to dark energy have been proposed. The big bang may have created this large-scale wave in space-time. Both the dark energy and dark matter have unknown sources, the scientists cannot conventionally observe all of it.