Scientists have recently discovered this darkness by means of special equipment and submarines that have enabled them to dive into the depths of the oceans. It is clear that the second set of waves are the surface waves that we see, because the verse mentions that above the second waves there are clouds. Scientists have recently discovered that there are internal waves which occur on density interfaces between layers of different densities. Internal waves at interface between two layers of water of different densities. The internal waves cover the deep waters of seas and oceans because the deep waters have a higher density than the waters above them.
Internal waves act like surface waves.
They can also break, just like surface waves. Internal waves cannot be seen by the human eye, but they can be detected by studying temperature or salinity changes at a given location.