Dark Energy: fiction or reality?

Abstract

Is Dark Energy justified as an alternative to the cosmological constant Λ in order to explain the acceleration of the cosmic expansion ? It turns out that a straightforward dimensional analysis of Einstein's equation provides us with clear evidences that the geometrical nature of Λ is the only viable source to this phenomenon, in addition of the application of Ockham's razor principle. This contribution is primarily a review of the mainstream in the interpretation of Λ because it is at the origin of such a research program.