In Surah Yunus (10:5), the Quran declares: "It is He who made the sun a shining light (diya) and the moon a reflected light (nur) and determined for it phases - that you may know the number of years and account [of time]."
The Quran uses two distinct Arabic terms for the light of the sun and the light of the moon: diya (ضياء) for the sun and nur (نور) for the moon. This subtle linguistic distinction is of remarkable scientific precision.
The historical context
In the 7th century, the distinction between the light emitted by the sun and that reflected by the moon was not known. The ancient Greeks, particularly Anaxagoras (5th century BC), had hypothesized that the moon reflected the sun's light, but this idea was largely rejected and forgotten. For centuries, many civilizations considered the moon as a source of its own light.
The scientific confirmation
Modern science has confirmed that the sun is a star that produces its own light through nuclear fusion, while the moon is a dark body that only reflects the sun's light. The moon's brightness is nothing but solar light reflected by its surface.
The Arabic term diya (ضياء) denotes an intense, self-generated light, while nur (نور) denotes a reflected or transmitted light. The Quran therefore uses precisely the appropriate term for each celestial body, a distinction that science only established in the 17th century with the work of Galileo and Kepler on the nature of celestial bodies.
This same distinction is repeated in other verses, notably in Surah Al-Furqan (25:61): "Blessed is He who has placed in the sky great stars and placed therein a burning lamp (siraj) and a light-giving moon (munir)." The term siraj (lamp) denotes an intense light source, while munir (illuminating) denotes a body that shines by reflection.
The scientific significance
The Quranic distinction between the light of the sun and that of the moon is a striking example of the scientific precision of the Quranic text. A 7th-century man could not have known the physical nature of solar and lunar light, yet the Quran uses distinct terms that correspond exactly to the physical reality discovered by modern science.