Dark matter Dark matter is belived to be a from of matter thought to account for approximately 85% of the matter in the universe and about 27% its total mass - energy density or about 2.241×10⁻²⁷ kg/m³ most dark matter is thought to be non baryonic in nature . Dark matter could be white dwarfs the remnants of cores of dead small and medium size stars or dark matter could be neutron stars or black holes the remnats of large stars after they explode . Baryonic - baryonic matter should only include matter composed of baryons . In other words, it should include protons, neutrons and all the objects composed of them (i.e. atomic nuclei), but exclude things such as electrons and neutrinos which are actually leptons. where is all the dark matter ? The first variety is about 4.5% of the familiar baryouns which also make up the luminous stars and galaxies most of this baryonic dark matter is expected to exist in the form o...