Matter is formed by particular structures in the geometry of space-time (it is common to assume that a particle is something like a small wrinkle in space-time that maintains its structure when moving along it: an electron is a type Of stable structure in space-time for example).
Let's go with energy, a physical system (a particle or a set of particles) is characterized by these things:
1. It has a specific location in space-time (it is contained in a region thereof).
2. It has a defined physical state, subject to temporal evolution (there is an equation that predicts how the system changes under the influence of things outside the system).
3. It can be associated with a physical quantity called energy.
So for me energy is NOT a thing, but a number that can be assigned to everything contained within the universe (this number measures something that is not the thing itself but does give you clues as to how that thing is going to behave In the presence of another).
Nowadays we know with certainty that the matter, although at the sight of the senses a liquid or a solid or the transparent air that surrounds us fills all our surroundings, the fact is that with the invention of the microscope and many experiments done by chemical and physical seems That matter and radiation (matter is what has mass, and although to prove it we must turn to the theory of relativity, everything you can in principle "leave quiet", are formed by particles, with many gaps between They, what happens is that there are forces that make them very far apart (for their size) from the others, and despite the great gap between them, we touch things and we can not penetrate them (if they are solid), Or we are inundated by occupying everything that is around our body in the case of liquids or gases.
