Big Bang cosmology

Big Bang cosmology is the leading scientific theory explaining the origin of the universe. It posits that around 13.8 billion years ago, the universe began from an extremely hot and dense state and has been expanding ever since. Initially, all matter and energy were concentrated in a singular point. Over time, this expansion cooled, allowing particles to form atoms, then stars and galaxies. Evidence supporting this theory includes the cosmic microwave background radiation—faint afterglow of the Big Bang—and the observation that galaxies are moving away from us, indicating that the universe is still expanding.