Two related preprints from Astrophysics Letters describe the “dark bubble” framework, which is presented as a string-theory motivation for a positive cosmological constant and several new physical consequences. The first paper focuses on experimental implications at distances around 10^{-5} meters (micron scales). It argues that, unlike some extra-dimension gravity models that strengthen gravity at short distances, the dark bubble model predicts gravity becomes weaker than Newtonian gravity at these scales. It also provides explicit proposed deviations for tabletop tests.
The second preprint reviews and extends the framework’s connections to other ideas, including a “dark dimension” of micron size and a “fat graviton” scenario in which gravity effectively stops probing shorter distances. It similarly predicts a weakening of gravity at distances comparable to the dark-dimension scale. Both papers further claim cosmological consequences, including a reduction of the effective gravitational force at high energy densities that can produce an early inflation period without additional components beyond radiation. They also report predictions for a measurable positive spatial curvature and discuss links between the model’s higher-dimensional construction and the observed matter content of the universe.
