We investigate why the universe remains in a stationary state without expansionor contraction. In a previous work, we proposed a static, finite, and closed universemodel in which cosmological redshift arises from photon energy attenuation (DOI:10.5281/zenodo.19251753). In the present paper, we introduce the assumption thatmatter and space are physically inseparable and always scale together. Under this assumption, any global scale change becomes observationally undefined, and the universeis effectively static.As a supplementary consideration, we examine the nature of photons in a finite universe and derive an effective photon rest mass from the maximum possible wavelengthdetermined by the global size of the universe. The predicted value, mγ = h/(cλ0), isof order 10−33 eV/c2, well below current observational upper limits.Previous studies have mainly focused on experimental upper limits of the photonmass, whereas in this model it is derived from the global structure of the universe.
Hirokazu Nagata (Mon,) studied this question.