In the age of modern science, scientists have discovered through research that the waters of the two seas do not merge. For example, the waters of the Roman Sea and the Atlantic Ocean cannot mix with each other , because there is on-ray. But in that era there was no instrument for conducting such experiments. In such an era, the Qur'an says: Marj al- Bahrain yaltaqian binhama barzakh la yabghiyan ( Surah Ar -Rahman 19-20) He has made two rivers flow side by side. There is an on-judgment between the two , which they do not transgress. (Surah Ar-Rahman 19-20) It has been narrated in Tafseer that the two seas mean sweet and salty sea. Allaah has created both types of seas on earth. In some places the two seas meet together , an example of which can be seen in different parts of the world. However , in places where both sweet and salty rivers flow side by side, the waters of both are distinct and distinct. On one side there is sweet water and on the other side there is salt water. Somewhere this sweet salt water also flows up and down. Although water is a liquid and a fine substance, it does not mix with each other. Allaah says ( interpretation of the meaning): “ And who made the earth habitable , And put on-ray between the two seas ? So is there any other god with Allah ? Rather, most of them do not know. ( Surat an- Naml : 61) It has been narrated elsewhere: “ Whoever dies in Bahrain, this torment of the Euphrates and this is the sweetness of the waters and the barrier between them . He left an on-verdict , an impenetrable cover (Surah Furqan 53). Costa is a famous scientist. He studied seawater , which is why the two seas do not merge. One sea water of one color and one taste of another sea water of another color and another taste. He went to sea and witnessed, then he devoted his life to research on water and established a doctrine called Constant Theory. A few days later, a Muslim scientist met him , and when Costa presented his doctrine to him, he said, "You have just done research. " I can show you research from hundreds of years ago. When the Muslim scientist showed him the Qur'an, Kosta was shocked and he accepted Islam and was blessed. French scientist Jacques V. Costa , who is famous for his underwater research , realized that the Roman Sea and the Atlantic Ocean were chemically different from each other. He studied the seabed near the confluence of two seas in Gibraltar to find out the truth, and found that a freshwater fountain unexpectedly overflowed from the north shore of Gibraltar [Marukesh] and the south shore [Spain]. This large waterfall moves rapidly through both seas at a 45 degree angle and acts as a dam, taking the shape of a comb tooth. As a result of this activity, the Roman Sea and the Atlantic Ocean could not merge with each other. There is no way to understand with the naked eye the separation or the screen that lies between the two oceans . Because apparently all the seas seem to be the same. Not only him , but the entire marine scientists failed to find this obstacle. In 1942, they set up more than a hundred marine stations and tested them via satellite. Which of the following is a barrier to the union of two seas ? They tested the light there , tested the air and examined the soil and found no cause for obstruction or curtain. Here a light , dense color of water is observed. Which cannot be perceived with the naked eye. Scientists even take pictures through or through the perceptual method from a distance of the Earth-satellite center for a more in-depth understanding of the subject and for further experimentation. The waters of the Mediterranean Sea are dark blue and the waters of the Atlantic Ocean are light blue . The water of the Mediterranean Sea is much higher than that of the Atlantic in terms of density-warmth and salinity. More interestingly , the waters of the Mediterranean Sea have penetrated hundreds of kilometers into the Atlantic Ocean through the Gibraltar Cell or the surface of the sea floor, and even after reaching a depth of 1000 meters, its above characteristics and color have not changed. Although there are strong waves , strong currents and rough waves between the two, they do not mix with each other and cannot cross each other. Since there is a screen between the two.