Since the big bang, a cosmic battle has been under way between matter (both dark matter and ordinary) and dark energy.
The gravitational force that draws massive objects such as galaxies towards each other works against the expansion of the universe. But astronomical observations show that the universe’s expansion has, oddly, been speeding up. This led scientists to conclude that dark energy, a mysterious force acting as a sort of anti-gravity, permeates the entirety of space. And dark energy appeared to be at a significant advantage in the cosmic tug of war.
