On the Invariance of the Spacetime Interval
Classical Physics
2025-12-17 v1 General Relativity and Quantum Cosmology
Abstract
We present a geometric proof of the invariance of the relativistic spacetime interval based solely on the constancy of the speed of light, and the homogeneity and isotropy of spacetime. The derivation is based on a simple construction involving light rectangles, whose areas remain invariant across inertial frames. Based on this construction, we also derive the Lorentz transformations.
Cite
@article{arxiv.2512.14446,
title = {On the Invariance of the Spacetime Interval},
author = {Marco Moriconi},
journal= {arXiv preprint arXiv:2512.14446},
year = {2025}
}
Comments
11 pages, 3 figures; to appear in The Am. J. Phys