Every second, a faint glow of light which originated 14 billion years ago falls on the Earth from all directions. Cosmic Microwave Background radiation or CMB is actually the residual heat of creation—the afterglow of the Big Bang, according to Scientific American
Proof of Big Bang
The discovery of these radiations was important evidence for the Big Bang theory. In the 1960s, radio astronomers Arno Penzias and Robert Wilson were mapping signals from the Milky Way
Pigeon droppings?
During their experiment, they found a mysterious signal. Suspecting it could be a result of pigeon droppings on the antenna, they cleaned the equipment. When the signals persisted, they realised it was radiation from space. Thus they discovered CMB by chance
Physics Nobel
The duo shared the Nobel Prize in Physics in 1978. Their citation read, “This unexpected discovery, offering strong evidence that the universe began with the Big Bang, ushered in experimental cosmology”
The CMB is the oldest light we can see—the farthest back both in time and space that we can look. It is a relic of the universe’s infancy, a time when it was not the cold dark place it is now, but was instead a firestorm of radiation and elementary particles