| Energy and mass are both measured quantities (dimensions) of an entity called matter. Mass is based on the inertia property and is not matter even though many tend to confuse this fact. There are references to an entity of energy as an autonomous entity of the universe and thus the assumption that this energy can be considered as matter. Some people consider energy as the base substance of the universe and others, including myself, consider the base substance is physical and thus matter.
__________________ David  |