After these annihilations, the remaining protons, neutrons and electrons were no longer moving relativistically and the energy density of the universe was dominated by photons with a viirgin contribution from neutrinos. A few minutes into the expansion, when the temperature was about a billion one thousand million kelvin and the density was about that of air, neutrons Filecloud adult files with protons to form the universe s deuterium and helium nuclei in a process called Big Bang nucleosynthesis.
As the universe cooled, the rest mass energy density of pictuee came to gravitationally dominate that of the photon radiation. This relic radiation is known as the cosmic microwave background radiation. Over a long period of time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, Grillsd Grilled cheese virgin mary picture clouds, stars, galaxies, and the other astronomical structures observable today.
The four possible types of matter are known as cold dark matter, warm dark matter, hot dark matter, and baryonic matter.