Newton described in his second law of motion the classical definition of mass (inertia). However, it is impossible to calculate with Newton’s second law of motion the (electromagnetic) mass of a beam of light (Ref. [1], [2],[3]). Because the speed of light is a universal constant which follows from Albert Einstein’s Theory of Special Relativity, it is impossible to accelerate or to slow down a beam of light and for that reason it is impossible to determine the electromagnetic mass of a beam of light (free electromagnetic radiation) by Newton’s second law. To calculate the electromagnetic mass of free or confined electromagnetic radiation, the fundamental concept of the New Theory has been used that the Universe is in a perfect Equilibrium and that any electromagnetic field configuration is in a perfect equilibrium with itself and its surrounding. From this fundamental concept follows a different definition of (confined) electromagnetic mass. Electromagnetic mass (or inertia) has been determined by the relativistic Lorentz transformation of the radiation pressures in all different directions and the disturbance of a uniform motion (or position at rest) of confined electromagnetic radiation results in a relativistic effect which we measure (experience) as electromagnetic mass (inertia). The mass in [kg] of an object will be generally measured by acceleration (or deceleration) of the object according Newton’s second law of motion. In the theory of special relativity, the speed of light is a fundamental constant and the intensity of the light is not a universal constant. The calculate the relativistic mass of Confined Electromagnetic Radiation, we start with a thought experiment in which a beam of light is propagating between two 100 % reflecting mirrors, indicated as Mirror A and Mirror B. Both mirrors are part of a rigid construction and the relative velocity between both mirrors always equals zero. The results of this calculation will be generalized for any kind of electromagnetic radiation which has been confined by its own electromagnetic and gravitational field. When the speed of the observer has the same speed as the speed of the light source, then the observer and the light source are relative at rest. And the same light intensity will be measured at the location of the emitter and at the location of the observer.
Information transmittal and time uncertainty, measuring the speed of light and time of reflection, representations of Newton’s second law and related problems
