Not true, science knows what both mass and light are on a fundamental Earth level, but the new questions, involve, where does mass come from in the first place. Enter the theoretical God particle that some unproven mathematical model demands, and must exist for the model to be correct, but as we know, the model does not need to be correct. There is work currently being done, apart from the supercollider, that seems to be indicating that quantum spooky entanglement, is actually an instantaneous transmittal of information, which crushes the light as top speed in the universe postulate, which means throw away all books and begin again. So the frustrating thing, is knowing that we as a race, are discovering, that the more we know, that the less of what we knew yesterday makes any sense. However, what is mass and or light, are not questions that necessarily have an answer, in the form that we are looking for, or might even understand, if presented with.