Well, if we're going to nitpick, light has zero rest mass[0], but does have mass while in motion. This is how solar sails can work, since they use the momentum

Well, if we're going to nitpick, light has zero rest mass[0], but does have mass while in motion. This is how solar sails can work, since they use the momentum from the photons. [0] https://en.m.wikipedia.org/wiki/Invariant_mass https://en.m.wikipedia.org/wiki/Invariant_mass