In 1896, Marconi was successful in sending signals through a wireless telegraph to a distance of a few kilometers away. However, how would it be possible to provide intercontinental communication via radiotelegraphy and radiotelephone? In 1901, together with his assistants, G.S. Kemp and P.W. Paget, Marconi successfully transmitted and received transatlantic signals between Poldhu, Cornwall and New Foundland, Canada, using a kite aerial at Signal Hill in Cornwall, England. It was Edward Appleton who first discovered that radio waves were broadcast around the world after they are reflected back from the ionosphere, one of the highest electrified layers of the atmosphere that contains large concentrations of charged particles (ions) and free electrons. Electromagnetic waves that are sent from radio transmitters to outer space are reflected back to every corner of the Earth after hitting this gas and plasma layer that is composed of charged particles. Thus, radio and radiotelephone communication is made possible for the benefit of human beings. After that time, being able to use a law that had been ordained by the Supreme Creator, human beings were able to reach a level that enabled them to conduct transatlantic communications via radiotelegraphy. But what makes radio waves so special?

Radio waves

The frequency spectrum of electromagnetic waves begins from the “sub-sound frequency region” (1Hz) stretching up until cosmic rays (Figure 1). Radio communication is made using the electromagnetic waves that form part of this frequency spectrum. Radio communication systems can be classified into four groups relating to their frequency regions:

– LF/MF (Low Frequency/Medium Frequency)

– HF (High Frequency)

– VHF/UHF (Very /Ultra High Frequency)

– SHF (Super High Frequency)

Specifications of radio waves are taken into account in this classification. The main element that makes radio waves similar or different from each other is the frequency band that determines their wave length. Radio waves move at the speed of light (300 thousand km per second), much faster than sound itself, so to find the wave length of a radio wave, we divide its velocity by its frequency.

Frequencies used within the radio frequency spectrum measure between 20 KHz and 30 GHz. Theoretically, the high frequency band is between 3 and 30 MHz, while in practice it is between 1.6 and 30 MHz. The interval between 4 and 18 MHz is the most-widely used region in the spectrum.

The atmosphere

Our Lord, Who incessantly prepares the Earth in a beautiful manner, also protects all of life with a perfect shield called the “atmosphere.” Scientists have divided the atmosphere into seven layers in order to reveal the unknown facts about it. These seven layers are different from each other in terms of temperature, pressure and humidity levels, and the natural events that occur in them. If we ascend from the Earth toward the sky, we pass through the layers of the troposphere, stratosphere, ozonosphere, mesosphere, thermosphere, ionosphere and the exosphere. All these layers cover a distance of about 3,000 km. Each of the atmospheric layers serves a vital cause. Every layer has many functions, ranging from the formation of rain clouds to the prevention of harmful beams reaching the Earth, from reflecting radio waves to inactivating meteors. One duty of the ionosphere that we are aware of today is to act as a reflector and distributor for radio waves.

The ionosphere and distribution of radio waves

Good transatlantic radio communication depends upon many factors. Depending on the frequency of the radio waves, the season of the year, the position of the Sun, the location of the broadcasting area and the time of day, the communication area may vary from 100 km to 10,000 km.

Radio waves are propagated around the Earth in two forms, either as ground waves or as sky waves (Figure 2). In high-frequency radio communication, it is important to choose the best frequency for the time and means of propagation.

Starting from 50 km above the Earth and stretching 440 km, the ionosphere is filled with a high concentration of free electrons and gases. Why is the ionosphere important for transatlantic radio communication? The electrified ions that fill the whole of the ionospheric layer that completely surrounds the Earth reflect radio waves from all directions to every part of the world. According to their frequencies and ionization, radio waves are completely absorbed in the ionosphere and they are either partly refracted and distributed to the outer space or are reflected and returned to the world. The electromagnetic waves within a range of 30 MHz can return to Earth after being reflected by the ionosphere.

It is accepted that the ionosphere is formed at different ionizing levels in different layers, known as D, E, F1, and F2 (Figure 3). The ionization level in the outer layers of the ionosphere is higher than that of the inner layers. The D layer, the innermost layer of the ionosphere, is 76-93 km above the Earth and is characterized by low ion densities and low collision frequencies of electrons and ions with neutral particles. Serving to absorb most energy below 7 MHz, this layer is ionized during the daylight hours, completely disappearing at night. It reaches full ionization level just after sunrise and is at its peak at noon time, immediately losing energy after sun-set.

The E layer is the region of the ionosphere that was discovered first. In this layer, molecular ion production is at its peak at about 110-115 km above the Earth. There are plenty of molecular gases at this height. This layer is a suitable platform from which radio operators can reflect signals to distant stations. Reaching a maximum at noon, the ionization in the E layer decreases towards the end of the day, disappearing completely at midnight. Moreover, at unpredictable intervals, ionized gas clouds accumulate in certain regions of this layer. This can be detected by the variable dense clouds of ionization that occur in the E layer due to the spatial and temporal structure in the ionizing particle precipitation. The plasma density of the E layer can be greatly changed because of these occasional formations. These formations, which are called “sporadic E layers,” are used by radio amateurs for long distance VHF (Very High Frequency) operation. Since the plasma density in layers D and E is highest at noon and present during the other hours of daylight, these layers are used in the daytime.

The next layer of ionosphere exists at about 160 and 400 km above the Earth and consists of layers that have a higher density of free electrons caused by the ionizing effect of solar radiation. Since the density of gas molecules at this height is low, ion and electron collisions occur very slowly in this layer. When solar radiation is high (during the day) this layer can be divided into two independent regions, F1 and F2. The F1 layer is present at 152 and 203 km above the surface of the Earth. During the night, the F1 layer merges with the F2 layer. The F2 layer exists at 250 and 400 km above the surface of the Earth. The majority of HF (shortwave) transmissions are propagated by the F2 layer, which is the main reflecting layer for HF communications both at day and at night. Reaching its maximum level of ionization just after midday, the layer is at its minimum just before sunrise. The F2 layer can be used for 10-20 MHz during the day and 3-8 MHz during the night. Since the F layer exists at a very high altitude, it is exposed to sunlight for longer periods of the day and it dissipates very slowly at night. In this case, the only layer of the ionosphere that can be used during the night is the F layer, which I is composed of the F1 and F2 layers.

Solar radiation, and consequently ionization, alters periodically. For instance, as the days are long during the summer months, ionization is also high at this period. During this time, radio waves are absorbed or attenuated more in layers E and D, and propagation covers only a small area. However, since the days are shorter during the autumn and winter, less solar energy reaches these ionospheric layers. Hence, low frequencies can easily pass through the weakly ionized D and E layers and reach the stronger F layer from where they can be propagated over long distances.

Another long term factor in ionization is the regular 11-year activity cycle of sun spots. Sun spots are believed to be caused by violent eruptions on the Sun and they are characterized by unusually strong magnetic fields. During periods of maximum sun spot activity, the density of ionization increases in all the layers of the ionosphere. During these periods, the D layer absorbs more and the critical frequencies of layers E, F1 and F2 are higher, therefore, for long distance communication higher operating frequencies over 30 MHz should be used. During terms of minimum sun spot activity, the E and F layers have weak ionization, so they cannot reflect the radio waves back onto the Earth. In this period, frequencies over 20 MHz are not used much. Along with this regular variation, “sudden ionospheric disturbances (SID)” also negatively affect the propagation of radio waves. SID are thought to be caused by severe solar eruptions, but the real cause of this phenomena is still not clearly known. (Figure 4)

Sudden ionospheric disturbances can disturb radio communication for hours or even days. Strong solar eruptions cause a sudden abnormal increase in the ionization density in the D layer, hence even the high frequency radio waves coming from the side of the Earth that is facing the Sun are completely absorbed by this layer and frequencies above 2 MHz are unable to penetrate it. When SID occurs, long distance propagation of HF radio waves may be completely blocked.

Ionospheric storms are another disturbing factor for radio communication. When a solar eruption occurs, it takes between 20 and 40 hours for the magnetic storm to reach the Earth. The ionospheric storms cause the F2 layer to virtually lose its ion density. At this time, when the range of frequencies used for communication is much smaller than normal, communication is only possible at lower frequencies.

Frequency and propagation routes in radio communications

The definition of the frequency to be used for radio communication is an important parameter for ensuring healthy propagation. For this, the Maximum Usable Frequency (MUF), and the Lowest Usable Frequency (LUF) are determined. Frequencies over MUF penetrate the ionosphere, shooting right through the ionosphere and going out into space, whereas frequencies below MUF are reflected. LUF is the lowest frequency that is completely absorbed in the D layer. To conduct good communication, a frequency, calculated as MUF×0.85, should be used. This frequency may be lower at night and higher during the day.

Apart from the propagation frequency, the path that is chosen to transmit the radio waves from one point to the other also must be calculated accurately. The angle at which the radio waves enter the atmosphere (angle of incidence) defines the path that will be covered by the waves on their way to Earth. The angle of incidence should be small enough for the waves to be reflected back to Earth and large enough so that the waves will not penetrate the ionospheric layer. Smaller critical angles should be used for smaller frequencies and larger critical angles should be used for larger frequencies so that they will not penetrate through the ionospheric layer and be lost in space.

Consequently, apart from periods when solar eruptions are strong, radio waves that are over 30 MHz frequency are not reflected and can penetrate the atmosphere and reach outer space, hence making the communication between outer space and the Earth possible.

For transatlantic communications conducted via communication satellites, radio waves over 30 MHz are used. Artificial satellites imitate the ionospheric layer, their original source of inspiration, and act as a reflector for these waves (Figure 5). Waves coming from the Earth are reflected by these satellites if they are within their coverage area. However, these manmade satellites have very limited coverage areas. Although they are produced with the highest technology available, their cost is very high and they last only for about 25 years. Nevertheless, for radio waves lower than 30 MHz, the ionosphere, that covers the whole of our planet, acts as a natural satellite. Because of this characteristic of the ionosphere, we do not have to focus at any certain point. Moreover, there is no need for maintenance, nor any energy supplement, and the ionosphere is permanent. The atmosphere has been granted for our service for as long as Earth survives. Through searching and exploring new facts about the universe and all beings, we realize more and more that neither meaningless nor useless matter exists in the material world of creation. Therefore, we are better able to understand that the universe is packed with wonderful favors and blessings that are addressed directly to humanity.

At first, air seems to be quite simple” gaseous mixture of atoms, ions, and molecules; 78.1 percent nitrogen, 20.8 percent oxygen, and some trace amounts of carbon dioxide, hydrogen, argon, neon, and krypton, just like spice and salt for a meal. So far, nobody has disliked this meal,’ whose mysteries and secrets are revealed upon investigation.

Air as a Light Source

Air is a mirror that illuminates our surroundings. We cannot read a book or a magazine in outer space, for there is no illumination there. Outer space is a vacuum. Since it contains no molecules or atoms off which the sun’s light and heat can reflect, its darkness cannot be pierced. Since the moon has no atmosphere or layer of gaseous matter to scatter the sun’s light beams, its surface is bright but the space just above it is dark. The Creator of the sun and the eye also created the atoms and molecules in the air and put them at our disposal so that we could see.

Now let’s analyze air, since we depend upon it for our very lives. We inhale oxygen with every breath, and once in our body it burns our food and thereby provides the energy for all bodily functions and maintains bodily heat. It exits through the throat, mouth, and teeth in the form of words.

Nitrogen, the largest component of air, dilutes the concentration of oxygen and makes the air we respire more pleasant. Without it, oxygen would be hazardous and irritating to our lungs. Nitrogen also is a natural fertilizer absorbed by soil and passed onto various micro-organisms in the soil and then to plants. As a result, one of our basic nutrition source components is produced: proteins. This flow of nutrition from plants to animals to people is a fascinating example of mutual benefit and co-operation.

Carbon dioxide, another gas, has only a trace (0.03 percent) presence in air. And yet every year, with the help of plants, it is used to synthesize billions of tons of sugar in a process known as photosynthesis. Plant leaves absorb carbon dioxide, the roots absorb water, and when sunlight is added the final product is glucose, the vital food for every living organism.

Oxygen is another by-product. The resulting energy produced by burning glucose enables all bodily cells to function. Photosynthesis stores the energy from the sun as bond energy between carbon atoms in the sugar. Thus the sun is our food source, as the Qur’an points out: And if you ask them who sends down rain from the sky and gives life therewith to Earth after its death, they will reply, Allah!’ Say: Praise be to Allah!’ But most of them do not understand (29:63).

Let’s travel in the atmosphere to learn more about this Divine source of resources. Now we are 10 kms above Earth’s surface. We cannot breathe here, and so must use our oxygen tanks. At 13 kms, we start to feel a great pressure that almost causes our eyes and blood vessels to burst.

The Unfelt Load

The gases forming the air apply a pressure of 1 kg per cm2 on our skin. The resulting air pressure plays the biggest role in the meteorological events, for strong storms and hurricanes occur when there is a 1 percent change in it. All living things live comfortably and unconsciously with this pressure.

As we go higher into the atmosphere, the density of gases and atmospheric pressure decrease. Also, the pressure of our bodily fluids rises (our bodies are 75 percent water) so much so that we might wonder if they will vaporize or rush out of our bodies. The air has a great weight, although we think the opposite. Most of us do not know that air applies a pressure equal to 1 kg on a fingertip-sized part of our bodies. We do not feel such pressure”calculated to equal 15 tons of air”because its Creator balances it with an inner pressure that is equally intense. Any disturbance in this balance threatens human life. This is why people cannot live at high altitudes, why mountaineers experience severe headaches and nosebleeds, and why astronauts have to wear pressurized space suits.

Layers of Atmosphere

Scientists divide the atmosphere into several layers, each of, which is unique in terms of its heat, pressure, humidity, and the events taking place within it. The first layer is the troposphere, which extends as high as 16 kms above sea level. This layer, which features the perfect circulation of air and matter, is the home for such events as rain, snow, and wind. At its upper edge, its temperature can reach -56’C.1

But the Owner of the universe, following His own rules, makes the atmosphere work as a giant water distribution center. Light breezes circulate thousands of tons of water (as clouds) and guide the water to the soil that needs it. Air’s circulation is moderated so perfectly that no area is ever always wet or dry, and even deserts and rainforests receive what they need to survive.

As Earth’s axis has a slant of about 23′, northern countries receive less energy than southern countries. The result of this seeming disparity in energy levels is the efficient flow of hot air to colder areas so that each area has its energy needs met. Hot air forms low pressure systems as it rises, while cold air forms high pressure systems as it sinks. Wind patterns blow cold air to the south and hot air to the north, forming an ideal system that spreads water vapor, as well as heat, energy, and even pollen, throughout the globe according to need. All of this allows the storage of heat at the equator in the form of energy to spread air and wind around the planet”a sort of global heat machine programmed by its Creator to serve life.

Air temperature drops by 0.61’C for every 100 meters increase in altitude.2 When the ascending air goes into troposphere (the kitchen of the atmosphere), its steam condenses into small droplets. Then clouds, a sign of God’s Mercy, start to form. The thin droplets in these clouds transform into separate ice crystals whenever the temperature drops below 0’C, just like a large army, and fall to Earth as snow.

While doing all of this, the air in our lungs and veins helps to weave colorful motifs on each plant’s leaves and blossoms. While bringing rain with clouds, it conveys pollen from one flower to another. On its weak shoulders it carries tons of water as well as airplanes, spreads light and transports heat, and brings sounds of all frequencies to our ears and many different smells to our noses. No mistake is ever made.

In warm weather, air’s lightness and gentle blowing bring subtle and deep meanings to our heart’s ear. Sometimes it assumes the form of a storm, a blizzard, or a tornado that rips apart everything in its path to warn those who do not understand its acts and do not thank God for the blessings it conveys. Through such events, people understand their weakness and turn to their Creator. Those who read and ponder the Book of Universe carefully, especially the page for air, observe such events as Divine indications of truth or warnings that should be heeded.

An Amazing Filter

The troposphere, the atmosphere’s first layer, is 8 kms thick at the poles and 17 kms thick at the equator. Its highest point is around 22 kms. After this comes the stratosphere, which is about 50 kms thick and has a higher temperature. This layer prevents the sun’s high energy radiations from reaching Earth. The ozone layer, which is vital for life on Earth, is located in the stratosphere. Ozone, which filters the sun’s hazardous rays, is a compound made of three oxygen atoms. The ultraviolet rays convert oxygen molecules into ozone by combining with oxygen.

Some human-made chemical products harm the ozone layer and thus enable ultraviolet rays to reach Earth’s surface. One result has been an anomalous increase in cancer rates, as high-energy ultraviolet rays have very short wavelengths and thus can potentially break the bonds of DNA molecules. These waves, if they reach Earth, also heat up Earth’s atmosphere. An increase of 10 C is enough to cause blood and sap to boil.

Thus we can understand the ozone layer’s role in maintaining this very sensitive balance. Those who claim that such perfection is casual are unable to read the signs God sends to His creatures.

A Comparison

To appreciate these blessings, consider the moon: Its diurnal temperature reaches 120’C, while its nocturnal temperature plunges to -150’C. It is a desolate, silent, and dead place constantly afflicted by meteor showers and ultraviolet rays. This does not happen on Earth, because the carbon dioxide and water molecules in its atmosphere absorb the sun’s excess radiation. This limits the temperature rise during the day and preserves heat for the night. The atmosphere screens hazardous radiation from the sun during the day and preserves the temperature at night. This roof’ gives our planet a moderate climate, while other planets suffer from extreme temperatures.

The water in oceans and seas, which cover approximately 75 percent of Earth’s surface, regulates Earth’s climate. It protects the land from the freezing polar climate and from the scorching temperature of the tropics. Land easily radiates the energy absorbed from the sun’s radiation and thereby ensures a moderate climate.

Although the oceans and seas face higher radiation rates, it is hard to raise their temperatures. Millions of solar calories from the sun are needed to raise the water’s temperature by only a couple of degrees Celsius. Also, this water does not cool easily. This resistance to temperature change enables it to regulate the climate and provide water to the land via evaporation. If the land-sea/ocean ratio were lower, Earth would be full of deserts. Given this, how can we not see the plan of the Artist who created the universe with infinite wisdom?

Meteors

The next level, the mesosphere, extends for the next 80 kms.3 It protects Earth from the meteors that used to scare the Vikings. This is vital, for many meteors fall to Earth every day, as Earth’s gravitational pull attracts them. Also known as shooting stars, they disappear when they enter the atmosphere, for the combination of great speed and atmospheric air reduces them to dust. Without this shield, we would face the meteors every day, just as the astronauts who visited the moon discovered. This dust then goes on to form clouds by joining with water particles until a certain density is reached and the resulting mercy of rain falls to Earth according to a physical and mathematical plan.

A Mirror for Radio Waves

Now we come to the ionosphere, which extends for the next 400 kms. Here, all particles have either a negative or a positive electrical charge.

People were astonished when the wireless radio was invented. However, scientists saw a huge problem: Since radio waves must travel on a straight path, and Earth is a sphere, they could travel only 100 kms. But in 1901, England and Canada were able to communicate via wireless radio across the Atlantic ocean because particles in the ionosphere have an electric charge that makes them reflect radio waves coming from Earth back to Earth. The ionosphere was seen to be like a large echo chamber in space.

Thus we see that God took the needs of all centuries into consideration when creating Earth. As our knowledge increases, we discover what He placed there at the time of creation to benefit us at a later date.

Magnetic Shield

Next comes the exosphere, which extends another 2,000 to 3,000 kms. Here, there is almost no air and friction. Molecular collisions gradually decay, and the relative meaning of temperature no longer applies. Thus most satellites are placed in orbit at this layer.

A compass always points north on Earth because of the magnetic field lines. If we follow this direction, we reach the North Pole. Such knowledge enables us to navigate on land, sea, and air quite easily.

The poles are situated at opposite ends of a hypothetical axis passing from the middle of a hypothetical circle forming the equator. But they are only geographical”not magnetic”poles. The magnetic North Pole is located at the edge of the Ellef Ringes islands in northwestern Canada, 1,290 kms south of the geographical North Pole. The magnetic South Pole is located at Adelie Land in Antarctica. There are various explanations, but no solutions, about what causes these magnetic fields. One theory claims that magnetic field lines (Van Allen Belts) surround the Earth because of the hot liquid iron and nickel at its center.

This layer, the seventh, largest, and final layer, functions as a magnetic shield. The magnetosphere consists of belts formed by magnetic densities. The closest belt to Earth is 4,000 kms distant. The second belt is 16,000 kms distant and can effect things up to 30,000 kms distant. These invisible belts catch and prevent dangerous cosmic rays and charged particles from entering the lower levels by changing their direction. Thus these cosmic rays (having the force of atomic bombs) and solar winds (high-energy electron-carrying atoms) do not reach Earth. Before any of the atmosphere’s properties were discovered, the Owner of Earth and the sky told us about the atmosphere’s shielding: And We have made the sky a roof withheld (from them). Yet they turn away from its portents (21:32).

The Balance in the Atmosphere

Atmospheric gases, because of their nature, seek to scatter into space while gravity works to pull them down and keep them. However, a perfect balance ensures that neither development will happen. Using Earth’s mass, radius and gravity, and several other factors, the precise calculations and adjustments that maintain this balance are beyond even the imagination of humanity.

If Earth were closer to the sun, its air would be hotter and these hot gases would rise and leave the atmosphere. If Earth were further away from the sun, they would be pulled down onto Earth’s surface. If gravity were a little more or less than its current value, the same situation would occur. In addition, the incoming heat must be held for some time. This is done by carbon dioxide.

And yet our planet is a warm and lighted home moving rapidly in cold, dark space. In this home, we have everything we need. To appreciate what we have, all we have to do is compare it with the moon. Do those who seek the source of these actions in blind nature or unconscious and unintelligent reason know that they must assume that all lifeless and unconscious particles must have the knowledge of how to create the universe; how to meet every need and action of all parts of existence (especially of humanity), and also have absolute power to make these processes function with complete perfection for all of eternity?

Footnotes

1. www.geog.ouc.bc.ca/physgeog/contents/7b.html.
2. Ibid.
3. www.onlineastronomy.com/astr161/lect/earth/atmosphere.html.