1400 years ago, the concept of internal waves in the ocean was unknown. These waves, which occur beneath the surface, were only discovered recently. Yet, the Quran seems to describe such waves long before they were scientifically understood.

Internal waves are gravity waves that oscillate within a fluid medium rather than on its surface. These waves occur in stratified water bodies, where the water layers have different densities due to variations in temperature or salinity. These waves can travel across vast distances in the ocean, typically within the pycnocline—the layer where density differences are most pronounced. Unlike surface waves, which are driven by wind, internal waves move through the water layers, often traveling at slower speeds but with significant amplitude.

Hydrologists and oceanographers have confirmed the existence of internal waves, especially in the deeper ocean layers, where these waves can exist in complete darkness. Internal waves have wavelengths that can extend from hundreds of meters to tens of kilometers, and they occur deeper than the photic zone where light cannot penetrate. As such, these waves travel in the deep, dark waters of the ocean. - Internal waves are confined to these deeper layers and can travel undetected by light. They are created by the difference in density between various water layers and can be powerful, similar to the surface waves but occurring at much deeper depths.

The Quran in Surah 24:40 (An-Nur) describes the ocean's layers and waves in a manner that is strikingly consistent with our modern understanding of internal waves:

In this verse: - The "waves topped by waves" could describe the internal waves below the surface, with "waves" being the surface waves and the "clouds" symbolizing the layers of water or atmospheric conditions above. - The layers of darkness, described as "depths of darkness, one above another," refer to the increasingly dark waters as you go deeper, which is where internal waves occur, away from the reach of visible light.

In the story of Noah, the Quran mentions "waves like mountains" (Quran 11:42), which may metaphorically refer to the towering nature of internal waves in the ocean. These waves, being extremely large, could resemble the heights of mountains as described in the Quranic narrative.

Given that internal waves were only confirmed by hydrologists and oceanographers in recent years, the question arises: How could an unlettered man living 1400 years ago have known about these deep ocean phenomena, if he was not a prophet of Allah ﷺ? The Quran’s accuracy in describing such scientific details challenges the notion of human knowledge at the time and suggests a deeper source of understanding.