Cosmic Neutrino Background

The cosmic neutrino background is a proposed background of particle radiation made up of neutrinos left over from the early universe, sometimes called relic neutrinos and abbreviated CNB. The name uses the Greek letter nu, the standard symbol for a neutrino in particle physics. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/