The first principles underlying Einstein's mass-energy equivalence, expressed by the equation E=mc², can be summarized as follows:
Energy Conservation: The principle of energy conservation states that energy cannot be created or destroyed; it can only be transformed from one form to another. This principle was well-established before Einstein's work.
Relativity: Einstein's theory of special relativity introduced the concept of relativistic mass and the idea that the laws of physics should be consistent for all observers in uniform motion. It challenged the traditional notion of absolute space and time and introduced the concept of spacetime.
Speed of Light: According to special relativity, the speed of light in a vacuum (denoted by "c") is an absolute constant and is the same for all observers, regardless of their relative motion. This principle fundamentally changed our understanding of space and time.
From these principles, Einstein deduced the mass-energy equivalence relationship, which states that mass (m) and energy (E) are interchangeable and can be considered different forms of the same underlying entity.
The equation E=mc² quantifies this relationship, where "E" represents energy, "m" represents mass, and "c" represents the speed of light. It states that the energy (E) of an object is equal to its mass (m) multiplied by the speed of light squared (c²). This equation suggests that a small amount of mass can correspond to a large amount of energy, highlighting the immense potential contained within matter.
The first principles of energy conservation, relativity, and the constancy of the speed of light, combined with Einstein's mathematical formulations and reasoning, led to the derivation of the mass-energy equivalence relationship encapsulated by the equation E=mc².