Why is there Difference among Free Space, Mass and Energy? Why Space-Time Shows, at Times, Free Space, at Times, Mass and the Other Times, Energy Only

In general physics, free space is a region that has no gravitational or electromagnetic fields. It is used as an absolute standard of reference. Non-technically, it is also called absolute vacuum or theoretically ?perfect? vacuum. It is a standard reference medium for electromagnetic effects. The ?perfect? vacuum is a concept of electromagnetic theory. This concept is an ion from nature, a baseline or reference state that is unattainable in practice, like the absolute zero of temperature. About the properties of free space, it is characterized by the fixed defined value of the parameter which is known as the permeability of free space or the magnetic constant and the fixed defined value of the parameter which is called the permittivity of free space or the electric constant. Maxwell showed that the permeability is a quantity related to density, and he also showed that the dielectric constant, the reciprocal of permittivity, is a quantity related to transverse elasticity. He deliberately used these quantities in Newton's equation for the speed of sound to obtain a wave speed that is equal to the speed of light. This famous calculation concludes around equation (136) in Part III of his 1861 paper On Physical Lines of Force with the estimate that =1, 95, 647 miles per second. The electric and magnetic fields in these waves are related by the fixed defined value of the characteristic impedance of vacuum. In this paper, I will show the differences among real free space, masses and energies. I will also show that the space-time fabric, at times, looks like free space, at times, masses and the other times, energies only.