A few days ago I had just finished completing the Koran Surah Ar-Rahman. Each finished Maghrib prayer I had a habit of reciting the Quran. Surat Ar-Rahman is the letter that "magic" in my opinion, because in it God repeatedly explained, "So, where else favors of your Lord will ye deny?". I would like to comment on this post about the letter later, God willing.
This morning I received a photo of fellow lecturer ITB through the list. This amazing photo, because these photos prove Surat Ar-Rahman verse 19 and 20, which reads:
"He let two seas, they meet together. Between them is a barrier which is not exceeded, respectively. "(Q.S. Ar-Rahman: 19-20)
Praise be to God, the Almighty Allah, the Exalted. It turns out that sea water do not mix it really exists. I have often read that paragraph, but still do not know where is the sea water never mix it. Another verse tells the same phenomenon occurs in Surah Al-Furqan verse 53, which reads:
"He Who has let free the two seas (side by side); that is palatable and the other salty and bitter; and He placed between them a barrier and prevented. "(Q.S. Al-Furqan: 53)
Two ocean do not mix it is located in the Strait of Gibraltar, the strait that separates the continents of Africa and Europe, precisely between the countries Morocco and Spain
The result of my googling on the internet, I found a scientific explanation of the sea. Here I quote my results from various sources on the internet:
Flow Strait of Gibraltar is very large at the bottom. This is because the difference in temperature, salinity, and density of water (density) it. The sea water in the Mediterranean Sea (Mediterranean) has a density and a higher salt content of sea water in the Atlantic Ocean. By their very nature, the water will move from high density to areas with lower density of water. So that the flow in the Strait of Gibraltar move to the west, toward the Atlantic Ocean. And if this water will be mixed with water in the Atlantic Ocean?
NO !. Why ?? Apparently when seawater from the Mediterranean to the Atlantic Ocean, they do not mix. As if there are partitions that separate the two types of water. Even the boundary between the two sea water is very clear. The sea water from the Atlantic Ocean over a bright blue. While seawater from the Mediterranean Sea darker. This natural wonder. Not only is it a strange behavior of both the sea water. Ternyarta, seawater from the Mediterranean that do not want to mix with sea water from the Atlantic Ocean is to infiltrate under sea water coming from the Atlantic Ocean. The water of the Mediterranean Sea is infiltrated under water from the Atlantic Ocean at a depth of 1000 meters below the surface of the Atlantic Ocean.
How did it happen?
The story goes like. The sea water from the Atlantic enters the Mediterranean Sea or the Mediterranean through the Strait of Gibraltar. Both have different characteristics. The water temperature is different. The salt concentration is different. The density of water (density) airpun different. The second time it met in the Strait of Gibraltar, the character of water from each sea has not changed. From the ferry that we were, still can be seen clearly where the water from the Atlantic Ocean, and where the water from the Mediterranean Sea or the Mediterranean Sea. Come to think logically, inevitably mixed, in fact, do not mix. Both seawater it takes a long time to mix, so that the characteristics of melt water. Evaporation of water in the Mediterranean Sea is very large, being the water of the river that empties into the Mediterranean Sea was reduced yet. That's why the Atlantic Ocean water flowing into the Mediterranean Sea.

Alut water currents in the Strait of Gibraltar
The nature of the ocean when it meets, according to modern science, do not mix with each other. This has been explained by oceanographers. Due to differences in density, surface tension prevents the water from the ocean is not becampur one another, as if a thin wall that separates them.
Mediterranean sea, dark blue, infiltrated to a depth of 1000 m above sea level, in the Atlantic Ocean, and goes as far as hundreds of miles in the Atlantic Ocean and its characteristics remain unchanged. Subhannallah.