Why is an alpha particle heavy?

An alpha particle is heavy primarily because it is composed of two protons and two neutrons, making it a helium-4 nucleus. This combination of particles contributes to its relatively high mass compared to other types of radiation, such as beta particles (electrons) or gamma rays (photons). The strong nuclear force that holds these nucleons together also adds to the overall mass of the alpha particle, making it significantly heavier than lighter particle emissions.