Rest Energy and Potential Energy: Physics Foundations and a Cosmic Perspective

This paper explores the fundamental relationship between rest energy and gravitational potential energy, contrasting localized Newtonian mechanics with large-scale cosmological models. While rest energy represents an intrinsic property of mass and potential energy denotes a system-dependent position within a force field, attempting to equate specific potential energy to the square of the speed of light locally introduces significant kinematic and observational contradictions, such as requiring non-physical spatial scales of nearly a light-year or time-decaying gravitational accelerations. However, when evaluated across the observable universe as a holistic system, total gravitational potential per unit mass evaluates naturally to the magnitude of the speed of light squared. This cosmological equivalence bridges mass-energy equivalence, Mach’s Principle, and the Zero-Energy Universe hypothesis. To distinguish local position-based potential energy from this universal boundary condition, this paper proposes the term Cosmic Potential Energy (or Machian Potential Energy) to describe the global gravitational potential scale of the universe.