An Astronomical and Geometrical Analysis of the Star of Bethlehem Narrative (Matthew 2:1–12), in the Perspective of Kepler's Intuition

Preliminary note
This manuscript constitutes the reference English version of a scientific preprint deposited on Zenodo under the reference: https://doi.org/10.5281/zenodo.18509520
Translated versions in French and Spanish are available.
The English version shall be regarded as the authoritative version for academic citation.

Version note.
This document is version 3 of the Zenodo repository.
Version 1: initial deposit of the article in English.
Version 2: addition of French and Spanish translations; scientific content unchanged.
Version 3: introduction of a specific analysis of the planetary station of Jupiter at the third conjunction, accompanied by a dedicated figure (Figure 2), establishing the 4–5 day convergence between this event and the sky–earth kinematic synchronization window identified independently. This addition constitutes the main scientific contribution of the present version.

Abstract

This paper presents an interdisciplinary analysis of the Star of Bethlehem narrative as recorded in the Gospel of Matthew (Matt. 2:1–12), examining Johannes Kepler’s hypothesis that the phenomenon may correspond to the great conjunction of Jupiter and Saturn in 7 BCE.

The methodology is strictly rational and is based on a systematic confrontation between the ancient text and verifiable astronomical data, including planetary ephemerides, the geometry of the sky as observed from Judea, geographical constraints associated with the journey from Jerusalem to Bethlehem, and the historical chronology of the reign of Herod the Great. Each statement in Matthew’s account is treated as an independent constraint that must be simultaneously satisfied; failure of any single constraint would invalidate the model.

The analysis shows that the Jupiter–Saturn conjunction of 7 BCE, remarkable for its triple occurrence and extended duration, exhibits an apparent motion compatible with the biblical descriptions of the star's movement and stopping, without invoking supernatural explanations. In particular, the planetary station of Jupiter, identified independently from the same ephemerides, converges toward the sky–earth kinematic synchronisation window within an interval of only four to five days — a result obtained without any ad hoc adjustment, and constituting a strong element of internal consistency of the model. When realistic constraints on travel speed are introduced, a very narrow temporal window emerges. For a central and well-documented value of 6 km h⁻¹, the model uniquely selects the night of 24 to 25 December 7 BCE. A formal probabilistic analysis estimates at approximately 10⁻⁶ the likelihood that such a concordance results from chance alone. A finer analysis based on the same ephemerides further reveals an additional coherence at the hourly scale, with the timing of first visibility and meridian transit matching the duration of the terrestrial journey.

This study does not aim to establish a historical event nor to support a religious belief. It demonstrates, rather, that Matthew’s narrative is astronomically, geometrically, and mathematically coherent, and cannot be dismissed as scientifically incompatible on purely rational grounds.

Keywords:
Star of Bethlehem; Great conjunction (Jupiter–Saturn); planetary station; historical astronomy; astronomical ephemerides; kinematic modeling

Supplementary material includes an Excel table detailing the astronomical ephemerides and kinematic computations used in the analysis.

This version includes equivalent English, French, and Spanish versions of the same work.