Key takeaway
Quran 24:40 compares the deeds of disbelievers to "darknesses within an unfathomable sea which is covered by waves, upon which are waves, over which are clouds," so dark that "he can hardly see" his own hand. Oceanography shows that sunlight fades quickly with depth, and below about 1,000 m the sea is completely dark. It also shows that besides surface waves there are internal waves deep within the ocean, along boundaries between layers of different density.
The verse
أَوْ كَظُلُمَـٰتٍ فِى بَحْرٍ لُّجِّىٍّ يَغْشَىٰهُ مَوْجٌ مِّن فَوْقِهِۦ مَوْجٌ مِّن فَوْقِهِۦ سَحَابٌ ۚ ظُلُمَـٰتٌۢ بَعْضُهَا فَوْقَ بَعْضٍ إِذَآ أَخْرَجَ يَدَهُۥ لَمْ يَكَدْ يَرَىٰهَا ۗ وَمَن لَّمْ يَجْعَلِ ٱللَّهُ لَهُۥ نُورًا فَمَا لَهُۥ مِن نُّورٍ ٤٠
Or [they are] like darknesses within an unfathomable sea which is covered by waves, upon which are waves, over which are clouds - darknesses, some of them upon others. When one puts out his hand [therein], he can hardly see it. And he to whom Allāh has not granted light - for him there is no light.
Key Arabic terms
| Arabic | Transliteration | Meaning |
|---|---|---|
| بَحْرٍ لُّجِّىٍّ | baḥrin lujjiyy | a deep, vast, fathomless sea (from lujja, the deep body of the sea) |
| مَوْجٌ مِّن فَوْقِهِۦ مَوْجٌ | mawjun min fawqihi mawj | "waves, upon which are waves" |
| ظُلُمَـٰتٌۢ بَعْضُهَا فَوْقَ بَعْضٍ | ẓulumātun baʿḍuhā fawqa baʿḍ | "darknesses, some of them upon others" |
A layered description
The verse builds a picture from the bottom up: a deep sea; waves covering it; above those, more waves; above those, clouds. The result is layer upon layer of darkness. It is a parable: the disbeliever's state is like being lost in that darkness, "and he to whom Allah has not granted light, for him there is no light."
Light and depth
Seawater absorbs and scatters sunlight. Red light is absorbed within the first few meters, then orange and yellow, and so on. Most sunlight is gone by about 200 m (the limit of the sunlit zone). Below about 1,000 m lies the aphotic zone, where no sunlight penetrates at all and the only light comes from living creatures. Clouds and surface waves, which reflect and scatter light, reduce it further.
Internal waves
The ocean is layered by density. Internal waves travel along the boundaries between those layers, below the surface, sometimes with heights of tens to hundreds of meters. Fridtjof Nansen noticed their effect, "dead water," during his Arctic voyages in the 1890s, and Vagn Walfrid Ekman explained it in 1904. Many writers see "waves, upon which are waves" as describing deep internal waves beneath surface waves. Others read it as one wave piling over another in a storm.
Balanced assessment
Strong The Arabic wording directly supports the correspondence, and the fact is well established.
The verse describes a deep sea in terms that fit what modern oceanography reports: deep darkness built up in layers, and waves at more than one level. People in 7th-century Arabia had no means of diving to such depths. Both readings of "waves upon waves" are linguistically valid. The description is accurate either way, and the internal-wave reading makes it more striking.
Frequently asked questions
Does the Quran mention internal waves?
Quran 24:40 describes a deep sea "covered by waves, upon which are waves, over which are clouds." Many interpret this as deep internal waves beneath surface waves, which oceanographers described in the early 1900s.
References
Quran
- Quran 24:40, Saheeh International translation (Quran.com)
Science & history
Classical exegesis is summarized from the standard commentaries (e.g. al-Ṭabarī, Ibn Kathīr, al-Qurṭubī). See our methodology.
Cite this page
Quran Scientific Miracles. “Deep-Sea Darkness & Internal Waves.” https://quranscientificmiracles.com/topics/darkness-in-the-deep-sea/ (reviewed 2026-10-20).