What’s the Difference Between Dark Matter and Dark Energy.
The rest of the universe is far from empty, however. Dark matter accounts for 23.3 percent of the cosmos, and dark energy fills in 72.1 percent (source: NASA). Together, these materials make up a whopping 95.4 percent of the universe, so no wonder we're still trying to figure out exactly what dark matter and dark energy actually are.
The rest they call, for want of a better word, dark: 23 percent is something they call dark matter, and 73 percent is something even more mysterious, which they call dark energy.
Dark matter also plays a central role in structure formation and galaxy evolution, and has measurable effects on the anisotropy of the cosmic microwave background. All these lines of evidence.
Dark matter, a component of the universe whose presence is discerned from its gravitational attraction rather than its luminosity. Dark matter makes up 30.1 percent of the matter-energy composition of the universe; the rest is dark energy (69.4 percent) and “ordinary” visible matter (0.5 percent).
Dark energy, repulsive force that is the dominant component (69.4 percent) of the universe. The remaining portion of the universe consists of ordinary matter and dark matter. Dark energy, in contrast to both forms of matter, is relatively uniform in time and space and is gravitationally repulsive, not attractive, within the volume it occupies.
Although the names seem to imply that they are similar, dark energy and dark matter are not directly related. Dark energy is the force responsible for the acceleration of the expansion of the universe at an ever-increasing rate since the Big Bang. Dark matter, on the other hand, consists of the unseen particles that bind our universe—and even our own bodies—together.
The amount of dark matter in the universe will determine if the universe is open (continues to expand), closed (expands to a point and then collapses) or flat (expands and then stops when it reaches equilibrium). Understanding dark matter will also aid in definitively explaining the formation and evolution of galaxies and clusters. As a galaxy spins it should be torn apart. This does not.