What is cosmic microwave background
The cosmic microwave background (CMB) is a faint glow of electromagnetic radiation that fills the entire universe. It is the afterglow of the Big Bang, the event that is believed to have marked the beginning of the universe about 13.8 billion years ago.
The CMB consists of microwave radiation, which is why it is called the cosmic microwave background. It was first detected in 1965 by Arno Penzias and Robert Wilson, who were awarded the Nobel Prize in Physics for their discovery.
The cosmic microwave background is essentially radiation left over from the hot, dense early stages of the universe. When the universe was very young, it was extremely hot and dense, filled with a plasma of particles. As the universe expanded and cooled, the plasma gradually formed neutral atoms, allowing light to travel more freely. The light that was last scattered about 380,000 years after the Big Bang is what we see today as the cosmic microwave background.
The CMB is remarkably uniform in all directions, with only slight variations in temperature. These temperature fluctuations provide valuable information about the structure and evolution of the universe. They are believed to be the imprint of tiny quantum fluctuations that were present in the early universe and eventually gave rise to the formation of galaxies and other cosmic structures.
The study of the cosmic microwave background has greatly advanced our understanding of the universe. It has confirmed the Big Bang theory, provided evidence for the inflationary theory, and helped establish the current model of cosmic evolution known as the Lambda-CDM model. Additionally, precise measurements of the CMB have allowed cosmologists to determine the composition, age, and geometry of the universe.