The Big Bang Theory is the leading explanation for the origin of the universe. It proposes that the universe began as a singular, extremely hot and dense point about 13.8 billion years ago, and has been expanding ever since. This expansion explains the movement of galaxies away from each other and the presence of cosmic microwave background radiation—key evidence supporting the theory. Over time, matter cooled and formed stars, galaxies, and eventually planets, shaping the universe we observe today.
