Science in the Glorious Quran: Darkness and Internal Waves

“أَوْ كَظُلُمَاتٍ فِي بَحْرٍ لُّجِّيٍّ يَغْشَاهُ مَوْجٌ مِّن فَوْقِهِ مَوْجٌ مِّن فَوْقِهِ سَحَابٌ ۚ ظُلُمَاتٌ بَعْضُهَا فَوْقَ بَعْضٍ إِذَا أَخْرَجَ يَدَهُ لَمْ يَكَدْ يَرَاهَا ۗ وَمَن لَّمْ يَجْعَلِ اللَّهُ لَهُ نُورًا فَمَا لَهُ مِن نُّورٍ” (النور:40).

“Or (the unbelievers’ state) is like the darkness in a vast deep sea, overwhelmed with waves, above which are waves, above which are clouds; darkness, one above another.  If a man stretches out his hand, he cannot see it.” (Qur’an, 24:40)

Humans are unable to dive down unaided to a depth of more than 20 to 30 meters underwater. But, as one goes deeper and deeper with equipment or using a submarine, the darkness increases due to the successive disappearance of visible colors of light. Of course, darkness underwater increases many-fold in the presence of clouds in the sky, as stated in the above verse.

Scientists have recently discovered the presence of internal waves. These waves act like surface waves and can be detected by studying temperature or salinity changes at a given location in the deep water. They may also be observed from satellites due to surface roughness enhanced by sunlight backscatter.

Heavy clouds increase the darkness of the sea, many-fold (left). The sea surface reflects 3-30% of sunlight (right)

Almost all the seven colors of the light spectrum are absorbed one after another on the first 200 meters of ocean, except the blue light, which gradually decreases and completely disappears by the depth of 1000 meters

Internal waves at the interface between two layers of water of different densities

Waves of cold, saltier water (bottom layer) may rise up 300 m above the floor of the ocean into the above warmer water

Internal waves (marked with an arrow) made visible by sea surface roughness which enhances sunlight backscatter, Somalia, Africa