On the earth, water is recycled according to a certain "measure". Life on earth is dependant on this water cycle.
One of the items of information given in the Qur’an about rain is that it is sent down to Earth in due measure. This is mentioned in Surat az-Zukhruf as follows:
“It is He who sends down water in measured amounts from the sky by which We bring a dead land back to life. That is how you too will be raised (from the dead)”[Surat az-Zukhruf 43:11]
This measured quantity in rain has again been discovered by modern research. It is estimated that in one second, approximately 16 million tons of water evaporates from the Earth. This figure amounts to 513 trillion tons of water in one year. This number is equal to the amount of rain that falls on the Earth in a year. This means that water continuously circulates in a balanced cycle, in a “measure”. Life on Earth depends on this water cycle. Even if people used all the available technology in the world, they would not be able to reproduce this cycle artificially.
Even a minor deviation in this equilibrium would very soon give rise to a major ecological imbalance that would bring about the end of life on Earth. Yet, this never happens, and rain keeps falling every year in exactly the same quantity just as revealed in the Qur’an.
The proportion of rain does not merely apply to its quantity, but also to the speed of the falling rain drops. The speed of rain drops, regardless of their size, does not exceed a certain limit.
Philipp Lenard, a Nobel-prize winning German physicist, determined that the speed at which raindrops fall increases with drop diameter, up to a size of 4.5 mm (0.18 inch). For larger drops, however, the speed of descent does not increase beyond 8 meters per second (26 ft/sec). This is attributed to the shape of the falling drops, which increases their air resistance and prevents them from exceeding a certain speed.
As can be seen, attention is drawn in the Qur’an to a delicate adjustment in rain which could not have been known 1400 years ago.
The Water Cycle
In 1580, Bernard Palissy was the first person to describe the present day concept of ‘water cycle’. He described how water evaporates from the oceans and cools to form clouds. The clouds move inland where they rise, condense and fall as rain. This water gathers as lakes and streams and flows back to the ocean in a continuous cycle. In the 7th century B.C., Thales of Miletus believed that surface spray of the oceans was picked up by the wind and carried inland to fall as rain. In earlier times people did not know the source of underground water. They thought the water of the oceans, under the effect of winds, was thrust towards the interior of the continents. They also believed that the water returned by a secret passage or the Great Abyss. This passage is connected to the oceans and has been called the ‘Tartarus’, since Plato’s time. Even Descartes, a great thinker of the eighteenth century, subscribed to this view. Till the nineteenth century, Aristotle’s theory was still prevalent. According to this theory, water was condensed in cool mountain caverns and formed underground lakes that fed springs. Today, we have come to know that the rainwater that seeps into the cracks of the ground is responsible for this. This is described by the Qur’an in the following verses:
“Seest thou not that Allah sends down rain from the sky, and leads it through springs in the earth? then He causes to grow, therewith, produce of various colors.”[Al-Qur’an 39:21]
“He sends down rain from the sky and with it gives life to the earth after it is dead: Verily in that are Signs for those who are wise.”[Al-Qur’an 30:24]
“And We send down water from the sky according to (due) measure, and We cause it to soak in the soil; and We certainly are able to drain it off (with ease).”[Al-Qur’an 23:18]
No other text dating back 1400 years ago gives such an accurate description of the water cycle.
“By the Firmament which returns (in its round),”[Al-Qur’an 86:11]
WINDS IMPREGNATE CLOUDS
In one verse of the Qur’an, the “fecundating” characteristic of the winds, and the formation of rain as a result are mentioned:
“And We send the fecundating winds, then cause the rain to descend from the sky, therewith providing you with water (in abundance).”[Al-Qur’an 15:22]
The Arabic word used here is lawaaqih which is the plural of laqih from laqaha, which means to impregnate or fecundate. In this context, impregnate means that the wind pushes the clouds together increasing the condensation that causes lightning and thus rain. A similar description is found in the following verses of the Qur’an:
“Seest thou not that Allah makes the clouds move gently, then joins them together, then makes them into a heap?–then wilt thou see rain issue forth from their midst. And He sends down from the sky mountain masses (of clouds) wherein is hail: He strikes therewith whom He pleases and He turns it away from whom He pleases. the vivid flash of His lightning well-nigh blinds the sight.”[Al-Qur’an 24:43]
“It is Allah Who sends the Winds, and they raise the Clouds: then does He spread them in the sky as He wills, and break them into fragments, until thou seest raindrops issue from the midst thereof: then when He has made them reach such of His servants as He wills, behold, they do rejoice!” [Al-Qur’an 30:48]
In this verse, it is pointed out that the first stage in the formation of rain is wind. Until the beginning of the 20th century, the only relationship between the wind and the rain that was known, was that the wind drove the clouds. However, modern meteorological findings have demonstrated the “fecundating” role of the wind in the formation of rain.
This fecundating function of the wind works in the following way:
On the surface of oceans and seas, countless air bubbles form because of the water’s foaming action. The moment these bubbles burst, thousands of tiny particles, with a diameter of just one hundredth of a millimeter, are thrown up into the air. These particles, known as “aerosols”, mix with dust carried from the land by the wind, and are carried to the upper layers of the atmosphere. These particles carried to higher altitudes by winds come into contact with water vapor up there. Water vapor condenses around these particles and turns into water droplets. These water droplets first come together and form clouds, and then fall to the Earth in the form of rain.
As seen, winds “fecundate” the water vapor floating in the air with the particles they carry from the sea, and eventually help the formation of rain clouds.
If winds did not possess this property, water droplets in the upper atmosphere would never form, and there would be no such thing as rain.
The most important point here is that this critical role of the wind in the formation of rain was stated centuries ago in the Qur’an, at a time when people knew very little about natural phenomena…
Another piece of information about the fecundating aspect of wind is the role it plays in the fertilization of plants. Many plants on the Earth ensure their survival by spreading their pollen by means of the wind. Many open pollinated plants, pine and palm trees and similar, as well as flowering seed plants and all grasses are fertilized by the wind. The wind takes the pollen from the plants and aids fertilization by carrying the pollen to other plants of the same species.
This effect of wind on plants was unknown until very recently. When it was realized, however, that plants are divided into males and females, the fertilizing effect of the wind was also understood. The Qur’an indicates this fact in the verse,“… We send down rain from the sky, and produce on the earth every kind of noble creature, in pairs.”[Surah Luqman 31:10]
Modern data on Hydrology agrees perfectly with the Qur’anic description on the same subject. The water cycle is described in several other verses of the Glorious Qur’an, including 7:57, 13:17, 25:48- 49, 35:9, 36:34, 45:5, 50:9-11, 56:68-70 and 67:30.