Since 2020, aggregated from related topics
The cosmic microwave background (CMB) is a faint glow of radiation that fills the entire universe, leftover from the Big Bang that occurred roughly 13.8 billion years ago. It is the oldest light in the universe and provides valuable insights into the early universe and the formation of galaxies and large-scale structures. Scientists study the CMB to learn about the composition of the universe, its age, and the processes that shaped it over billions of years. Observations of the CMB have helped confirm the Big Bang theory and provide evidence for the existence of dark matter and dark energy.