Euclidean Moon Rotation

This site demonstrates in two independent ways—first by a rigorous geometric analysis, and second by a Python-based dynamical simulation—that the Moon does not rotate on itself. The same program also simulates longitudinal libration.

Article: Disk Rotation

Readers are strongly advised to begin with this article. It presents an analysis of the well‑known model representing the Moon during its revolution around the Earth. It formally demonstrates by pure Euclidean geometry that the disk of the model does not rotate on itself.

Article: Moon Rotation

This article depends on the first one. It argues that, because Euclidean geometry governs the space sciences of the solar system, the Moon behaves like the disk in the model, which means that it does not spin. In addition, it provides complementary explanations, consequences, and a critical review of several existing interpretations.

Article: Libration

Since the usual cinematic explanation of longitudinal libration is incompatible with a non‑spinning Moon, this article relies exclusively on dynamics. Libration results from two effects: the well‑known tidal locking and a second one, the roly‑poly effect.

A Python program performs a simulation in a very simplified academic case of mass imbalance in which the tidal‑locking effect is assumed to be null. This corresponds to the “libration” mode of the program. In a second mode, called “rotation”, where libration is assumed null, the program confirms by dynamics the result obtained by geometry. The full source code is provided.

Conclusion

Geometry as well as Newtonian mechanics lead to the same conclusion: the Moon does not rotate on itself. The libration effects can be explained without requiring any continuous rotation.