God has said in the Quran:
“Or (the unbelievers’ state) is like the
darkness in a deep sea. It is covered by waves, above which are waves, above
which are clouds. Darknesses, one above another. If a man stretches out his
hand, he cannot see it....” (Quran 24:40)
This verse mentions the darkness found in deep seas and
oceans, where if a man stretches out his hand, he cannot see it. The darkness
in deep seas and oceans is found around a depth of 200 meters and below. At
this depth, there is almost no light (see figure 1). Below a depth of 1000
meters there is no light at all. Human
beings are not able to dive more than forty meters without the aid of
submarines or special equipment. Human beings cannot survive unaided in the
deep dark part of the oceans, such as at a depth of 200 meters.
Figure 1: Between 3 and 30 percent of the sunlight
is reflected at the sea surface. Then almost all of the seven colors of the
light spectrum are absorbed one after another in the first 200 meters, except
the blue light. (Oceans, Elder and Pernetta, p. 27.)
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.
We can also understand from the following
sentences in the previous verse, “...in a deep sea. It is covered by waves,
above which are waves, above which are clouds....”, that the deep waters of
seas and oceans are covered by waves, and above these waves are other waves.
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. But
what about the first waves? Scientists have recently discovered that there are
internal waves which “occur on density interfaces between layers of different
densities.” (see figure 2).
Figure 2: Internal waves at interface between two
layers of water of different densities. One is dense (the lower one), the
other one is less dense (the upper one). (Oceanography, Gross, p. 204.)