This entry examines Surah ar-Rahman 55:5 — “the sun and the moon [move] by precise calculation” (bi-husban) — read alongside 6:96. The statement is true and elegant, but celestial regularity was already ancient knowledge, so the claim to foreknowledge here is weak and the entry says so plainly.
The source text
ٱلشَّمْسُ وَٱلْقَمَرُ بِحُسْبَانٍ
“The sun and the moon [move] by precise calculation,”
Qur'an 55:5 · Saheeh International
فَالِقُ ٱلْإِصْبَاحِ وَجَعَلَ ٱلَّيْلَ سَكَنًا وَٱلشَّمْسَ وَٱلْقَمَرَ حُسْبَانًا ۚ ذَٰلِكَ تَقْدِيرُ ٱلْعَزِيزِ ٱلْعَلِيمِ
“[He is] the cleaver of daybreak and has made the night for rest and the sun and moon for calculation. That is the determination of the Exalted in Might, the Knowing.”
Qur'an 6:96 · Saheeh International
What was understood in the seventh century
Seventh-century Arabs used lunar phases and star risings for timekeeping, and Babylonian and Greek astronomers had long produced arithmetic and geometric schemes predicting lunar and solar positions; the regularity of the luminaries was appreciated in learned circles well before the lifetime of the Prophet Muhammad (peace be upon him). What no one possessed was the underlying explanation — motions governed by a universal mathematical law. Celestial regularity was attributed to divine decree or to the mechanics of nested spheres rather than to computable physical dynamics. Arabia itself ran on the sky: the calendar was lunar, and the moon's phases governed months, markets, and pilgrimage, so the luminaries' reliability was a matter of daily dependence rather than theory.
The modern correspondence
Newton's Principia (1687) showed that solar-system motions follow from a single gravitational law expressible in exact mathematics. Modern ephemerides predict solar and lunar positions to extraordinary precision, enabling eclipse prediction centuries ahead, and lunar laser ranging now tracks the moon's orbit to centimeter accuracy; NASA's eclipse resources illustrate the predictive power involved.
Commentators cite bi-husban (“by reckoning, by precise calculation”) as an economical statement that the luminaries' motions are intrinsically mathematical. The verse appears frequently in scientific-sign compilations, though it is better characterized as consonant with celestial mechanics than as predictive of it. The phrase opens Surah ar-Rahman's litany of ordered signs, in which regularity itself is presented as the wonder.
Considerations and counterpoints
Critics point out that using the sun and moon to reckon time is exactly what every ancient calendar did, and that 6:96 itself glosses the pair as being “for calculation” — human timekeeping, a mundane observational fact. Babylonian astronomers were mathematically predicting lunar eclipses over a millennium before Islam, so even the stronger reading, that the motions themselves are governed by calculation, was foreshadowed in antiquity. The verse is thus devotional cosmology consistent with common knowledge rather than knowledge unavailable in the seventh century, which is the judgment reflected in this entry's rating. As with several entries in this section, the honest conclusion is that the verse states truly and beautifully what later science explained — a devotional fit, not a demonstrable foreknowledge.
Credibility rating: Tier 3 · Contested — The statement is true and elegant but celestial regularity was already the basis of ancient calendars and Babylonian predictive astronomy, so it does not clear the bar of knowledge unavailable in the seventh century.