The CMB (Cosmic Microwave Background)

The Cosmic Microwave Background (CMB) is the faint glow of radiation filling the universe, leftover from the early moments after the Big Bang. Around 380,000 years after the universe's birth, it cooled enough for atoms to form, allowing light to travel freely. This light has since stretched into the microwave range due to the universe's expansion, creating a nearly uniform background radiation. The CMB provides a snapshot of the universe when it was still very young, offering valuable insights into its origin, composition, and evolution.