Why is Cosmic Microwave Background an important discovery?
The CMB is a critical piece of evidence supporting the Big Bang theory. Its existence was predicted nearly 20 years before its accidental discovery, which was significant enough that the Nobel Prize in physics was awarded to its discoverers. According to Big Bang cosmology, the early universe was filled with a plasma consisting of atomic nuclei and free electrons, which was opaque to light. As the universe expanded and cooled, the nuclei captured electrons to form neutral atoms and molecules, and the opaque plasma became a transparent gas, allowing light and other electromagnetic radiation to travel freely through the universe. These “first light” waves have themselves expanded as the universe has continued to expand and are now observed in the form of microwaves with a black-body temperature of less than 3 degrees Kelvin. Further study of the CMB has revealed that it is nonuniform, and the nature of these slight variations can provide additional information about the distribution of m
