What is Dark Matter?
In astronomy and cosmology, dark matter is known to be a type of matter hypothesized to account for a large part of the total mass in the universe. Dark matter cannot be seen directly by a telescope. It does not emit or absorb light other then electromagnetic radiation at any significant level. Instead, dark matters existence and properties are known by its
gravitational effects on visible matter, radiation, and the large-scale
structure of the universe. Based on our standard knowledge of the standard model of cosmology, the total mass energy of the universe contains 4.9% ordinary matter, 26.8% dark matter, and 68.3% dark energy. This means that dark matter is estimated to make up 84.5% of the total matter in the universe, and 26.8% of the total content of the universe.