The Cosmic Microwave Background

The Cosmic Microwave Background (CMB) is faint radiation filling the universe, appearing as a uniform glow in all directions. It is the afterglow of the Big Bang, emitted about 380,000 years after the universe's birth when atoms formed and light could travel freely. This radiation provides a snapshot of the early universe, revealing tiny temperature variations that helped scientists understand its composition, age, and evolution. The CMB is foundational evidence for the Big Bang theory and offers clues about the universe's origins, structure, and expansion.