An Adaptive Mechanical Articulation to Illustrate Minkowski‘s Space-Time in Special Relativity

The theory of Special Relativity has the simple mathematical structure of linear (Lorentz) transformations between the space-time coordinates of two inertial systems with the singularity of the finite light velocity as the only complication. In contrast to this plainness the results are intuitively unapproachable, e,g. it took physicists half a century after Einstein (1905) to see through the consequences of length contraction when watching a moving object. Inspired by Esther Cabezas-Rivas in her great General Relativity lecture 2017 we built a mechanical model of the Minkowski two-space using the steel construction set of Märklin (based on Hornby’s Meccano from 1901). On the background of the space-time diagram with the calculated hyperbola of equal proper time, the model illustrates major properties of the Minkowski space-time like linearity, simultaneity, the Lorentz contraction and the Doppler effect and visualizes the singularity on the light cone. We discuss other mechanical realizations and the possibility to make the model a practicable analog computer for phenomena in Special Relativity.