One of the properties of seas
that has only recently been discovered is related
in a verse of the Qur'an as follows:
"He has let loose the two seas,
converging together, with a barrier between them
they do not break through." (The Qur'an, 55:19-20)
This property of the seas, that
they come together yet do not mingle with one
another at all, has only very recently been discovered
by oceanographers. Because of the physical force
called "surface tension", the waters of neighboring
seas do not mix. Caused by the difference in the
density of their waters, surface tension prevents
them from mingling with one another, just as if
a thin wall were between them. (Davis,
Richard A., Jr. 1972, Principles of Oceanography,
Don Mills, Ontario, Addison-Wesley Publishing,
s. 92-93.)
There
are large waves, strong currents, and tides
in the Mediterranean Sea and the Atlantic
Ocean. Mediterranean Sea water enters the
Atlantic by Gibraltar. But their temperature,
salinity, and densities do not change, because
of the barrier that separates them.
The interesting side to this
is that during a period when people had no knowledge
of physics, surface tension, or oceanography;
this was revealed in the Qur'an.
