Special Theory of Relativity (STR) is tested by a thought experiment involving the Lorentz contraction of two one-dimensional objects interrelating in the two-dimensional space. The assumed two-dimensionality is due to observation performed in the third inertial frame of reference, noncollinear with the previous two. The detailed analysis leads to the conclusion that STR cannot be consistently applied to the spacetime with two and, by extension, three spatial dimensions; therefore, fails as a theory applicable to the real world. While the consequences of this finding are developed in the author’s previous papers, this study focuses on the thought experiment and respective theoretical background.

Special relativity, Lorentz contraction, Lorentz transformation, Tangherlini transformation, Preferred frame, Quantum gravity