This unified theory of relativistic rotation is radical, and will undoubtedly turn the most conservative minds viscerally attached to standard models on their head: in fact, it rejects the physical existence of straight lines in favor of circular trajectories, gives a mechanistic interpretation to spin, and denies the reality of the dilation of the universe or the existence of dark matter. Yet it never questions observations, because facts are stubborn. The candidate theory for unification presented in this manuscript requires no mathematical background beyond the first two years of university education. It is essentially based on mechanics and its representation in Euclidean geometry. The main conceptual difficulty lies in following the logic of rotation rather than translation. So it takes a little time and patience, which few of us have, to shake up our physical intuition engine and recalibrate our scientific flair in the light of the Coriolis force.