Cosmology is the study of the cosmos, which is the entire universe. Someone who studies cosmology is interested in the structure, origins, and development of the universe.
In cosmology, the major theory of the origin of the universe is the Big Bang Theory, the idea that 12 to 14 billion years ago, a small amount of hot, dense matter began expanding, eventually cooling and forming the stars and galaxies we know today. Cosmos comes from the Greek word kosmos, which means world or universe, and cosmology comes from cosmos. Don't confuse cosmology with cosmetology, which is the study of beauty treatments.
