Universe Expansion and Gravitation Unified

Aims: The expansion of the Universe and gravitation are considered different fundamental properties of the cosmos. We explore whether they are connected and propose an equation that links and unifies them. This equation describes the expansion of space as related to the mass of matter in that space. An expanding frame of reference, defined as expanding at the same rate, is the natural frame for an observer since the observer is part of the Universe and expands with it. In this frame, the expansion of the Universe by itself accounts for phenomena previously ascribed to gravitation. Gravity is fictitious and unnecessary. Here, we show that universal expansion naturally manifests as “gravity”. Methods: A theory is presented that postulates a natural expansion of the observer’s frame of reference due to matter and a generalized universal principle of equivalence of acceleration and gravitation that extends to any frame. It is consistent with both the general theory of relativity and our knowledge about the expansion of the Universe. Results: We tested the theory positively by applying its equation to global and local scales of the Universe with available data. It is applied to a Universe of homogeneous mass and discrete two and three-body systems and other phenomena hitherto thought to be unrelated. The results show that the proposed equation is valid at any scale. The fundamental nature of the Universe, from which gravity and other properties are derived, is its expansion.