Neutrinos are tiny, nearly massless particles that are produced in nuclear reactions, such as those in the sun or during radioactive decay. For many years, scientists believed that neutrinos had no mass at all, but experiments have shown that they do possess a small amount of mass. This discovery has significant implications for our understanding of particle physics and the universe. The concept of neutrino mass is important because it challenges the Standard Model of particle physics, which originally stated that neutrinos were massless. Understanding how neutrinos acquire mass could help explain other mysteries in physics, such as the nature of dark matter and the imbalance of matter and antimatter in the universe.