We live in a cozy and dynamic home called the Earth, which moves through cold, dark space at a great speed. Everything we need can be found on this specially made spacecraft of ours. There is neither excessive cold nor excessive heat. A moderate and pleasant climate prevails. There is an average temperature which has been kept at a dynamic balance throughout the centuries. In short, the earth has been made just for us. In order to understand this better, we need only to look at our satellite, the moon. During the day on the moon there is a burning heat which can rise up to 120 C and at night-time there is freezing cold which can fall down to -150 C. The moon is a land exposed to meteors, ultraviolet rays and cosmic rays; it is desolate and silent with no signs of life whatsoever.
In our world, the most practical solutions exist for the most complicated matters; the simplest things have important duties and splendid mechanisms are developed from these to carry out the same. Thanks to these mechanisms, there is a moderate climate and there are ideal values of air, pressure, heat and precipitation. Let us briefly consider a few of these systems that contribute to maintaining the average temperature in the world. The exact amount of solar energy we need reaches the Earth, and the distance between the sun and the earth plays an important role in this. If we think about the freezing cold on Mars, which is farther away from the sun, or the burning heat - a heat which melts even lead - of Venus, which is nearer to the Sun, we can appreciate the special status of the Earth and how carefully chosen its position is. If the solar energy that reaches the Earth were to decrease by only 10%, the average temperature of the Earth would decrease, and subsequently our planet would be iced over with an ice layer measuring a couple of meters in depth. A slight increase of solar energy, however, would burn everything and eradicate life on Earth.
We should not ignore the fact that our planet is of such a size that it is able to keep its gases within the atmosphere in ideal amounts and proportions. Our planet could have been created as small as Mercury (1/8 the Earth's size) or as big as Jupiter (318 times bigger than Earth). A smaller planet with lower gravity would disperse gases into space and therefore would have no atmosphere. A bigger planet would keep all the gases within the atmosphere, including poisonous gases, due to its high gravity. Furthermore, the Earth would be uninhabitable due to high atmospheric pressure and density. The fact that carbon dioxide and water molecules are scattered throughout the air in sufficient amounts means that they absorb heat from the sunlight during the daytime, thanks to their highly absorbent potential. At night, when there is no sunlight at all, the air keeps the previously absorbed heat in, just like a greenhouse, preventing it from being released into cold space. During the day, the atmosphere serves as a curtain protecting the world from the harmful effects of the rays of the sun; at night, it serves as a blanket preserving the heat. Devoid of such a protective shield, the moon is scorched by the rays of the sun during the day and it freezes at night.
Do we owe the small difference in temperature between day and night only to the gases in the atmosphere, which function like a thermos flask? Of course not! We can observe that the time span (24 hours) in which our world completes its rotation is so perfectly adjusted that the difference in heat is kept at a minimum. If the nights were longer, the Earth would get too cold; if the days were longer, it would become too hot. Mercury, rotating very slowly, is a good example, the heat difference between day and night can reach up to 1,000 degrees.
Seas constitute one of the systems which help to adjust the climate. At first, we may find it strange that seas cover a far greater area than land. We have named the planet that plays host to us "the Earth". The word "earth" also means soil. However, most of the Earth's surface (70%) is covered by water, not soil. Thanks to this reality, neither polar cold, nor boiling tropical heat prevails on our planet. The land, which is heated by the rays of the sun during the day, radiates the heat it has absorbed, just like a radiator. As for the sea, which is a huge mass of water, it only warms up a few degrees, despite the millions of solar calories it takes in. Nevertheless, once it warms up, it does not grow cold easily. The oceans, which cover a larger area than land, supply water to the land through evaporation, as well as serving as a thermostat that regulates the climate and prevents it from becoming too hot or cold. If the oceans were to occupy a smaller area, there would be less evaporation and less precipitation; the land would turn to desert.
The air that is heated by the sun rises to be replaced by cold air. In this way, low pressure centers appear where there is hot weather and high pressure centers appear where there is cold weather.
The tilting axis of the Earth plays a significant role in keeping the average heat within tolerable limits. On the other hand, the way the mountain ranges are arranged and the 100 difference in temperature between the equatorial and polar regions lead to the creation of winds. If such a heat difference were to appear on a planet that had an even surface, nothing would stand in the way of the storms, and they would reach a speed up to 600mph. The Earth however, is provided with natural barriers that block powerful air currents. These barriers begin at the Himalayas and continue as mountain ranges through the Taurus Mountains and the Alps, ending with the Atlantic Ocean in the west and the Pacific in the east. Another mechanism that helps regulate the heat in the atmosphere is that of the ocean streams. Overheating generated in the equatorial region is transferred to the north and south by the ocean streams, balancing the heat in different parts of the world.
This is not the only way in which the Exalted Creator Who has absolute control over the systems balancing the heat in the atmosphere manifests His Power. He assigned the clouds a similar job. Hot weather causes evaporation, which leads to formation of clouds. Clouds prevent some of the sunlight from reaching the Earth, reflecting it like a mirror.
The atmosphere consists of approximately 77% nitrogen, 21% oxygen, and 1% argon and other gases. The majority of living organisms, including human beings have been created with a metabolism that needs oxygen. When carbon compounds react with oxygen, the outcome is energy, with by-products being water and carbon dioxide. When such a reaction takes place in our body, the energy obtained is transferred to the energy packs (tiny accumulators) called ATP, which we use in our cells. Since all metabolic activities require ATP energy, we constantly need oxygen and this need is met through respiration.
Given that oxygen is a vital substance for us, we might think that it would be better for us if there were more oxygen in the atmosphere. Fortunately, our Lord did not create the universe in accordance with such simple logic. It is estimated that every oxygen increase of 1% over a level of 21% will also increase the possibility of forest fires by 70%, owing to the high inflammability of oxygen. An oxygen rate over 25% would cause the majority of our greenery to be burned to ashes. All the tropical forests and arctic tundra would be destroyed and it would be impossible to prevent great fires. This all goes to demonstrate that the present oxygen rate in the atmosphere is at equilibrium.
In spite of constant consumption, the rate of oxygen and carbon dioxide in the atmosphere is maintained thanks to a wonderful transformative mechanism which runs smoothly without failure (that is if we do not damage it). While animals consume oxygen, they continually release carbon dioxide into the atmosphere; carbon dioxide is a poisonous gas for animal life. Plants however, perform just the opposite activity, transforming carbon dioxide into oxygen, and producing nutrients as well, the most common being sugar. In this way, billions of tons of oxygen are produced and released into the air everyday.
What if plants, like animals, were to carry out the same reaction, consuming oxygen and releasing carbon dioxide? In a short time, our planet would turn into an uninhabitable place. We would use up the oxygen in the atmosphere in a short time and all life forms would be eradicated. And how about a world where both animals and plants produce oxygen? The atmosphere would have such a flammable quality that even the tiniest spark would cause great fires.
Like the other gases in the atmosphere, oxygen is kept at an ideal rate, its benefit and harm being precisely balanced. This is nothing more than the result of a perfect adjustment made by 'Him'. There can be no coincidence in such splendidly created systems and nor can these things happen on their own.
The fact that the density of the atmosphere is ideal for respiration also indicates the impossibility of 'coincidence' in this delicate arrangement. No matter whether we feel it or not, we continue breathing every moment of our life.
We constantly inhale and exhale the air. The reason why we need to breathe so much is that there are billions of biochemical reactions taking place in our body all the time which can only be realized with oxygen. Oxygen is even helping you to read this article, for the millions of cells in your retina need to be supplied with oxygen. If the oxygen rate in your blood decreases, your vision blurs. All the cells that make up the muscles in our body have energy generating centers which function by burning carbon; in other words, they react with oxygen.
When we inhale, nearly 300 million tiny spherical bags (alveols) are filled with high-pressure oxygen. The oxygen in the capillaries that cover the cell walls is reduced and then is at a low pressure. This allows the oxygen in the air to be absorbed by the capillaries and to be carried away by the hemoglobin found in the red blood cells - the magnificent servants of our body. Then it begins to serve our entire body, starting with the heart.
The red blood cells which travel to the lungs from different parts of the body carry oxygen from the lungs to the energy centers of the cells and they carry the waste material - carbon dioxide - back again to the lungs. In this process, clean air (with oxygen) is inhaled and is exhaled with carbon dioxide. Obviously, both inhalation and exhalation are vital functions for which we should be thankful. The words we utter can be considered the fruit of the carbon dioxide we exhale. On the other hand, this waste gas is recycled into oxygen and sugar by plants.
The fact that 300 million tiny bags in our lungs have been constructed to fit into a limited area clearly indicates God's infinite knowledge and the fact that He is Omniscient. If these were to be spread out over the ground, they would cover an area as big as a tennis court. They should, logically, require a gigantic organ to carry them; think about how we would carry this organ around with us...
In spite of being so tiny, the alveols and alveolar tubes in our lungs are large enough to let air move freely, which is another sign reflecting His wisdom.
The atmospheric pressure at sea level is 1 atm. This means that 1 kilogram of pressure is applied over a square centimeter, an area that is only as large as the tip of one's finger. At sea level, 1 liter of air weighs 1 gram. As it is seen, the air has an immense pressure, in spite of its lightness.
The fluidity of air is fifty times greater than that of water. As a matter of fact, these values are very accurate and the fact that they are so is critical for our life. If the density of the atmosphere were to be slightly increased, breathing would become as difficult as sucking honey through a straw. Do not even think of saying "make the straw wider", i.e, making the alveolar tubes in our lungs wider. In such a case, the area contacting the air would be diminished and the lungs would be unable to receive a sufficient amount of oxygen to meet the needs of our body. The resistance of the air would be too great and it would be impossible to design a respiratory system capable of supplying the oxygen we need.
Several conditions that make life possible are only realized at certain values, and the atmosphere possesses precisely all of these values. All these only go to show how delicate His adjustments are.
What if the atmospheric pressure was lower, for instance, just 20% lower than it is at present? Given that the conditions of evaporation and boiling depend on the air pressure, more water would evaporate from the oceans and eventually the high humidity of the atmosphere would create a greenhouse effect on the Earth. In other words, there would be excessive heat in the world. And if the atmospheric pressure was twice as great, the humidity would be so low that there would be terrible drought, turning almost all of the land into desert.
Several conditions that make life possible are only realized at certain values, and the atmosphere possesses precisely all of them.
The air that is in front of our nose, ready to be of use to us, the ground under our feet, the night and day that follow one another in succession... the sun, the honey bee covering miles for us... When we contemplate all these, we realize that all their activities are directed to serve us.
The beings in this universe do not serve us from their own free will. It is crystal clear that all things point to a Creator Who takes care of us.
Our Creator has bestowed us with ears, providing the world of sounds for us. He has created a brain in our skull, a heart in our chest and a tongue in our mouth; these serve as devices by which we sense and appreciate His blessings that overflow from His treasures of Mercy. He has presented various fragrances, tastes and colors for our senses; He has created numerous species in order to help such devices fulfill their true duty. Only the atmosphere and what it covers will suffice as signs that indicate the ultimate truth. Study the following Qur'anic verse, that reminds us of the divine grace: "And He subjected to you what is in the heavens and the earth all together, (as a grace) from Him." The rest of the verse counsels us to reflect: "There are in that signs for a people who reflect." (45:13)