The study of the universe is called cosmology. T__ scope o__ this fi__ is extr__ large, encomp__ everything fr__ the smal__ particles t__ vast galaxies. O__ intriguing hypo__ in cosmology is the Big Bang Theory, according to which the universe began approximately 13.8 billion years ago from an infinitely dense point. Cosmologists also study dark matter and dark energy. They observe cosmic microwave background radiation, the faint glow left over from the Big Bang, to gather information about the universe in its early days.