# A scientist says light is matter because it made of particles called photons that contain energy, which is the equivalent of mass, using E=mc^2, state the extent to which his belief is justified?

Jul 5, 2018

He is wrong as he seems to have misinterpreted the formula $E = m {c}^{2}$, the formula is actually $E = \Delta m {c}^{2}$, which is a formula that relates mass defect to the energy released. Based on the formula, it is valid to say that any lost mass contains energy, but it cannot said that anything containing energy must have mass.