light doesn't have mass because it is mainly a wave with certain particle like characteristics. electromagnetic radiation has no mass. light is made up of the same things as Radioworks microwaves infrared, all of those have no mass. even though light as photons has particle characteristics, it has no mass. its not matter
Photons have mass, it is m=(hf/c^2) h Planck's constant f frequency c velocity of light But photons do not have rest mass That is, you dont have an electromagnetic radiation at rest. That is just getting around your question. It is in the nature of light to have zero rest mass is my best answer
Mass, Time and length are the basic quantities which are not defined. They are understood only by intuition. We started studying Physics with this as basis. -------------------------------- However, by proper choice of any three quantities which we can make as basis and derive all other quantities of Physics. ----------------------------------- Suppose we choose, energy, momentum and time as the fundamental quantity, then mass becomes a derived quantity. --------------------------------------... After Einstein's relativistic theory, the constant C, energy and momentum have become the basis for the law of physics. One derives the mass from energy. And mass of any object depends on the velocity and the velocity of an object depends on the reference frame. Energy, the velocity of light, and the momentum are alone independent of the reference frame. Now there is equivalence between mass and energy which cannot be accepted if we choose the mass, length and time as basic indefinable quantity. On the other hand if we choose energy as the indefinable quantity and which should be understood only by intuition, mass becomes a derived quantity and it should not be compared with the previous undefined mass. ============================= Light has no mass, if one takes mass, length and time as the basis of all quantities. Light has mass and in fact light itself is a mass, if energy and momentum are taken as the basis of all physical quantities. ==============================
Because light is just energy! Atoms emit photons and thus, light is generated!
there are virtually massless particles that are energetic like photons, but virtually don't mean really, every particle has mass, even if it's completely irrelevant because it's absurdly small.
