Reevaluating the Necessity of Dark Matter and Dark Energy within Cosmological Models

The existence of Dark Matter and Dark Energy is widely accepted within the Standard Cosmological Model. However, their introduction is not based on direct detection but rather on the need to reconcile observations with theoretical expectations. This paper explores whether the necessity of Dark Matter and Dark Energy arises inherently from our chosen cosmological framework rather than from an independent physical requirement. Regarding Einstein’s cosmological constant Λ, it was reintroduced into modern physics following supernova observations but, also after carefully analyzing the Baryon Acoustic Oscillations, it is difficult to overlook its connection to the standard cosmological model. The same applies to gravitational lensing, where classical optics is used, with distances estimated based on Redshift. While the rotation curves of spiral galaxies have not yet been successfully explained without invoking dark matter or alternative gravity models, it is equally true that the classical Newtonian potential—lacking any gravitomagnetic or frame-dragging contributions—cannot provide a definitive demonstration of the existence of dark matter. This motivates the search for non-approximated relativistic solutions before accepting dark matter as the only viable explanation. As for elliptical galaxies, their dynamical behaviour does not pose a fundamentally different problem: their mass profiles can be interpreted within the same framework used for spirals, without invoking additional non-baryonic components. If dark matter is not required to explain the dynamics of spirals, it is likewise unnecessary for ellipticals, which can be understood as merger end-products without the creation of new non-baryonic mass. Moreover, in virial mass estimates the radius R is not a direct observable but is inferred from the angular diameter multiplied by a cosmological distance that depends on the adopted metric. Our analysis therefore casts doubt on the necessity of dark matter in elliptical galaxies, while not providing conclusive evidence for a definite alternative. Finally, the current status of direct dark matter detection has been reviewed, which so far has yielded no conclusive results. To properly and comprehensively address a cosmological discussion, we must not focus solely on the standard model but instead consider multiple models. This analysis draws a clear line between its findings and a topic that, by its very nature, inevitably enters a speculative framework. The remaining topic is presented in the final appendices, including a brief exploratory note on a possible observational interpretation of certain CMB anisotropy features—developed without assuming a global FLRW geometry. The alternative model chosen as a reference does not invoke dark matter or dark energy, and maintains a reversible evolution of the CMB that contrasts with the standard kinematic picture.