A new perspective on Hubble's law through a four-dimensional spatial model

The recent observational capabilities of the James Webb Space Telescope (JWST) are opening new windows into the early universe, revealing distant galaxies whose apparent rapid formation poses significant questions to the standard ΛCDM cosmological model. Observations of galaxies at redshifts above 14 (see JADES-GS-z14-0), implying extremely old ages according to current FLRW metric-based distance assumptions, might stimulate a thorough reflection on fundamental cosmological principles. Will it be possible to explain all this without violating Hubble's law? But really, does violating the FLRW metric necessarily imply a violation of Hubble's law? The Big Bang theory remains a robust and widely accepted paradigm. Nevertheless, any of its potential modifications could have profound implications for related fields, including Quantum Field Theory. This raises a fundamental question: is there a basic aspect that needs a conceptual revision? Although ΛCDM has achieved remarkable successes, many of its validations implicitly assume the FLRW metric. Could this dependence potentially introduce circular reasoning into model verification? In this work, an alternative approach to the phenomenon of Galactic Redshift is proposed, offering a possible pathway for a careful modification of the ΛCDM model through the adoption of a non-FLRW metric. In this scenario, the Universe resides on the surface of a hypersphere expanding at a constant rate, with a radius growing as r = ct and with the Big Bang located at its center. This would explain why our physics manifests as if we were in a boundless system, despite the Universe having a finite volume: it suggests that, in the absence of Relativity, we would likely have been led to study an infinite and static universe. While other models propose a hypersphere expanding with r = ct, an analysis of their main features reveals fundamental differences. The novelty of the model presented here lies in its definition of the Hubble constant: its geometry suggests a linear relationship between galactic recession and the arc angle (not the arc length). This perspective does not contest the validity of Hubble’s law, but introduces different predictions about the past and the future, which cannot be determined solely from current observations. The use of the angle instead of the arc length produces significant implications, opening the possibility of applying Special Relativity to galactic recession. The redshift, which asymptotically approaches a time horizon of roughly 5 billion years after the Big Bang, implicitly explains why, at the boundaries of the observable Universe with JWST, we should not expect to see only "baby galaxies". Specifically, the 4-Sphere framework, often considered part of alternative cosmologies, could potentially be reconciled with the Standard Model. Based on supernova distance measurements, I suggest that the dismissal of a Doppler-type redshift interpretation for Galactic Recession might warrant further and careful reconsideration. As a pivotal outcome, we will ultimately illustrate how the 4-Sphere mode of operation implies that the spacetime structure must accommodate a universal speed limit, independent of direction or frame of reference. From this condition, the principles of Special Relativity follow directly: the constancy of the speed of light, the equivalence of inertial frames, and the Lorentz invariance of physical laws. This inductive methodology, synthesizing abstract thought and mathematical formulation, does not intrinsically furnish scientific proof; however, it undeniably strengthens the explanatory power of the model.