Light wave is a effect of the vabration of atom's sphere time-space determined by the double-focus principle. Light wave is a serial time-space spherical wave. light wave carries curvature and kinetic energy, but not mass.Suppossition that light wave transfers a equivalent mass is wrong. So, the mass-energy formula created by Einstein is also wrong. Energy is equivalent to the change in the curvature of time-space. Reference: THING AND ITS LAW ( ISBN 1-58939-525-5), chapter 2,5, published by Virtualbookworm.com publishing.Inc.