In our previous article where we discussed the mind-boggling complexity of our eyes’ retinas. We learned about the ten separate layers of cells, but we did not elaborate on the intricacies of their creation. We also learned how the substance in the cone cells, called rhodopsin, is destroyed on exposure to light and then regenerated in the dark. We thus touched on the wisdom behind the existence of both night and day.

The destruction of rhodopsin is caused by the generation of electricity after its contact with light. This electric impulse is transmitted from cones and rods to either horizontal or bipolar (having two poles) cells. The section between these two different layers of cells is called the outer plexiform layer, where horizontal cells receive electric impulses from rods and cones, and carry them to neighboring bipolar cells. The horizontal cells are also charged with transmitting electricity horizontally between rod and cone cells. The signals make it possible for shapes to be carried to the central nervous system in an appropriate contrast. Other signals are blocked so that the borders of the place of contact with light can be clarified in the brain, which does not receive an excessive load of signals. If it were not for these cells, it would be harder to perceive borders because the line of difference between two different colors would not become clear.

Bipolar cells have two opposite poles. They are created as one of two types, in accordance with their functions: one amplifies generated electric impulses, while the other inhibits the transmission of excessive impulses from around the perceived object to the brain. Bipolar cells provide the contrast necessary for making borders clear. They make clear vision possible, and yet most people have never heard of this wondrous gift inside their retinas!

How is contrast enabled?

Thanks to an innate ability, our brain does not occupy itself with regions that have the same color or the same light. It will not be stimulated much if, for example, a wall is completely white or a car is bright red all over. If, however, there are other colors on the wall, say, a white moon or star on a red background, then there will be more stimulation in the brain. Suppose we place the shape of a crescent on the wall. The stimulated parts of the brain will lie along the sharp ends of the crescent, not in the inside or outside of it. The stimulation in the brain is less associated with non-contrasting regions than contrasts in view. The higher the contrast, i.e. the greater the difference between light and dark areas, the greater the degree of stimulation.

Amacrine cells in the inner plexiform layer of the retina enable horizontal transmission. There are up to 30 different types of these cells, and they carry out at least five to six functions. For instance, one type of Amacrine cell transmits electric impulses from cones and rods to bipolar cells, then to other Amacrine cells, then to ganglion cells, and finally to the brain.

Another type of Amacrine cell responds strongly to the onset of the visual signal, while another to its completion. One other type reveals the difference in light intensity regardless of direction, while still others respond to the movement of a light point in a certain direction in the retina, causing a perception in the brain as to the direction of the light.

Further research may reveal yet more functions. Amacrine cells might have such functions as regulating the intensity of electric impulses specific to each wavelength and generating different levels of impulses for moving or stationary objects.

The function of the ganglion cells in the innermost layer of the retina is to help ensure that the electric impulse generated and corrected in the retina is eventually transmitted to the brain. Three distinct ganglion cells are identified in the retina. These cells are represented with the letters W, X, and Y. W cells are assigned the task of transmitting signals from rod cells, which produce black and white visual signals in the dark. Making up about 40 percent of all ganglion cells, they have diameters of less than 10 micrometers and transmit signals at a speed of 8 m/sec. It is evident that these cells are assigned the task of perceiving objects in the dark as rough, vague shapes.

X cells, on the other hand, transmit electric impulses to the brain, creating precise color pictures of objects. Making up 55 percent of ganglion cells, they have midsize diameters (10-15 micrometers) and transmit signals at a speed of 14 m/sec.

The largest of ganglion cells (with diameters as long as 35 micrometers), Y cells are assigned the task of transmitting instant changes in sight. Making up only 5 percent of ganglion cells, they send signals at speeds of 50 m/sec.

Sending intense signals in split seconds, Y cells inform the central nervous system immediately in case of a threat or an unusual encounter. When our body or eyes face a threat, these cells help protect us by warning the brain to move away from the threat or close our eyelids rapidly. If it were not for these cells, we would not be able to reflexively close our eyes and thus protect them. It’s incredible to ponder how complex these systems are – and how perfectly they’ve been created.

Between layers of cells there also lie layers of network that house neurons and their connections (synapses). These cells too have subgroups trained to carry out specific tasks. All of these cells are built according to certain specifications so that they can transmit stimuli to the brain when they receive light. Extremely severe visual problems develop when even a single layer of these types of cells is missing. Every one of the layers in our eyes is immensely special, and it is hard to imagine them to have been randomly placed there. It should be born in mind that this article simply skipped numerous elements of the retina and their chemical functions. Taking the precise measurements and mechanisms into account, we can only feel greater awe and love in the face of the incredible art devoted to the creation.

The first article can be found at https://fountainmagazine.com/2018/issue-126-november-december-2018/retina-the-mind-boggler

The eye is a miracle as it is. Even though we have a rough understanding of its basic anatomy, we are confronted with a much more complex miracle when we venture into the intricacies of its anatomy and the physiology of the act of seeing. We have theories about the many details – such as the perception and representation of mental images and their storage in the memory – but we still do not exactly know how the act of seeing works.

One of the most mysterious layers of the eye, the retina has an elaborate structure with a slew of functions. Not every eye surgeon dares touch the retina, which houses the most sensitive and special cellular layers. It is a three dimensional, crescent-shaped structure located in the back of the eye and is made up of ten super thin layers of cells that span the exterior part of the eye abutting the veins and its interiors.

Retinal layers

The ten layers that form the retina are:

1. Pigment (coloring matter) layer
2. Layer of rods and cones
3. External limiting membrane
4. Outer nuclear layer comprising rod and cone cells
5. Outer plexiform layer
6. Inner nuclear layer
7. Inner plexiform layer
8. Ganglion layer
9. Nerve fiber layer
10. Inner limiting membrane

These layers are incredibly sensitive and elaborate, and studying their intricate structure give a sense of awe.

Light for sight

Light first arrives at and penetrates through the cornea, the living glassy layer at the outermost layer of the eye. It then goes through the frontal fluid (aquesous humor) and the aperture called the pupil (pupilla). It hits the internal wall of the retina (the inside of the crescent) after passing through the lens in the eye and then the optic fluid filling up the chamber in the back. This alone is an interesting fact because it is much later that the light that gets to the retina reaches the layer of sensitive cone and rod cells, which perceive light. As these cone and rod cells are lined one after another for their protection, light reaches this outer layer of the retina after the ganglion cells, retinal layers and nuclear layers. Such an alignment leads to a reduction of acuity in the peripheral regions of the retina.

We have theories about the many details – such as the perception and representation of mental images and their storage in the memory – but we still do not exactly know how the act of seeing works

The central pit (fovea centralis)

The inner layers at the center of the retina, on the other hand, are drawn to the sides to prevent any loss in visual acuity. Resembling a pit, this section is much thinner than the periphery of the retina, so the layers that are likely to obstruct the passage of the light, and hence reduce visual acuity, are aligned specifically to allow light to directly hit cone and rod cells. Besides, cone cells, which are in charge of exact, colored sight, exist in this region, whereas rod cells, which are in charge of rough and uncolored (black and white) sight, do not.  The central pit where visual acuity is at its highest is for keen, colored, and exact sight. Why then is the rest of the retina not created for acute sight and why is this small section equipped with this ability?

As it turns out, if the entire retina had the ability to see keenly then it would not be possible for the eye to focus on a spot and accurately distinguish it from surrounding objects. If we could see the entire page of a book at a glance, for example, the lines would mix up in our brain. We would not be able to understand what we are reading. We normally start reading from the top of the written page and continue line by line as we focus on and take in each word. Our brain then can focus and perceive a single word accurately by restricting keen perception of the surrounding area.

The retinal pigment layer

The color black is known to absorb, not reflect, light. Thanks to such absorption, the layer made up of black pigments (melanin) or dyes prevents the reflection of light, which is crucial for visual acuity. This black substance functions like the black dye in the bellows of old cameras. If there were not any layer to absorb light, light would scatter off the wall inside the eyeball, thereby obscuring the sharpness between light and dark spots, which is essential for the formation of a clear image, and producing a blurry image due to the overall illumination of the retina.

People who lack this melanin pigment as a result of a genetic defect (Albinism disorder) have white hair, and they are oversensitive to light because the colored iris layer of the eye does not contain the melanin pigment, which refracts light. When an albino person enters a bright area, the light that hits the retina is reflected in all directions through the pigment-lacking retina and the white surfaces of the rigid layer underneath (sclera). Therefore, a ray of light that would normally stimulate a few cones or rods is scattered everywhere, stimulating all or most of the light receivers. As a result, visual acuity in albinos can only be between 20/100 and 20/200, even with the help of the best optical correction, which is a low value compared to 20/20 in normal sight. The joke that rabbits do not wear glasses because they eat carrots is based on the high concentration of vitamin A in this pigment, or black dye, layer of the eye. Indeed, vitamin A is a crucial factor for the health of these pigments.

Layer of rods and cones

Composed of 127 million light-sensitive receivers (photoreceptors), the retina is 0.2 mm thick at the yellow spot (macula lutea), where the image forms most clearly, and 0.1 mm thick at the edges of this area. The 120 million cylindrical rods in the retina are in charge of black and white sight (at twilight), and the 7 million tapered cones, of colored, colored and exact sight. The more common cylindrical rods are 50 µm (microns) in length and 1-5 µm in thickness. The less common cones are 40 µm (microns) in length and 3-5 µm in thickness.

The concentration of the cones increases toward the center of the retina and decreases toward the edges, to be outnumbered by the rods. In the cytoplasm of the cones and rods are stored substances that are sensitive to light (photosensitive) which break up when light contacts them and produce electricity in the cones and rods. In rods this chemical is called rhodopsin. In cones, on the other hand, are three substances corresponding to the colors red, green, and blue that are sensitive to the wavelengths of colored light. To be more exact, there are three separate cone cells that include one of these three substances. Chemically, the photosensitive substances in the cones are a little different from rhodopsins.

The destruction of rhodopsin by light energy

Rhodopsin, along with the color substances, fills up about 40% of rods and cones. They are made up of a protein called scotopsin and a molecule called retinene that is derived from vitamin A. When light energy is absorbed by rhodopsin or the color substances, rhodopsin starts to fade in as fast as one trillionth of a second. The underlying reason for this is that the electrons in the retinene (vitamin A) part of rhodopsin is activated by light, which alters the shape of the retinal molecule at a mind-boggling speed (one trillionth of a second). Extremely complicated and precise chemical and physical changes then take place. It is very difficult to monitor all of these biochemical changes, and they require specialization [1].

The regeneration of the rhodopsin destroyed by light

Rhodopsin destroyed by light is regenerated in the dark. Only in the twentieth century did we manage to partially identify the mechanism by which molecules with very specific geometric shapes decay at incredible speeds only to be regenerated later. It is wondrous that such knowledge and power are present in the cell allowing the light energy to destroy the molecule and the regeneration process is launched. The circulation between destruction and regeneration of the molecule continues throughout a lifetime [2]. Vitamin A is assigned a crucial task in the generation of rhodopsin in the dark. All-trans retinal is converted in the retina into all-trans retinol, which is then converted into 11-cys retinol with the help of an isomerase enzyme. Finally, 11-cys retinol is converted into 11-cys retinal, which in turn combines with scotopsin to form rhodopsin. Vitamin A is present both in the cytoplasm of rods and in the pigment layer of the retina. In this way, vitamin A is kept in reserve to be used for generations of new retinal. If, on the other hand, there is an excess of vitamin A in the retina, the excess amount is converted into retinal, by which the amount of light-sensitive pigment in the retina is lowered.

Night blindness

Night blindness appears in anyone who suffers a serious deficiency of vitamin A. Because there is a lack of vitamin A to be converted into retinal, rhodopsin amounts decrease dramatically. This disease is called night blindness as it is noticeable only in the dark or at night and does not affect sight during the day, due to the reduction of light for proper seeing. In daylight, however, cones can still be stimulated despite a similar decrease in color pigments. Night blindness typically only appears in people that have a low vitamin A diet because huge reserves of vitamin A are normally stored in the liver to be used for the eyes.

The human retina contains 400,000 light receptive cells per square millimeter. For comparison, this number is 680,000 in the retina of the owl, which needs to perceive even the slightest glow when hunting in the night. As another example, with 397,000 such cells the amount in the cat’s retina is almost the same as ours.

An average of 130 sight cells in the retina are connected to a ganglion (nerve node) cell. Constituting the nerve of sight, or the optic nerve (nervus opticus), every nerve fiber is connected to a ganglion cell. It takes about 15-60 seconds for the retinal optic nerves to adapt from dark to light, while it takes as long as 30-45 minutes to adapt from light to dark. The visual range of optic cells, i.e. the lowest and highest amount of light the eye can perceive, is between 10^-7 and 10⁶ nanometers. Light that is below or above this range is invisible to us because of its insufficient or overwhelming wavelength.

All the colors we see in the world are named according to the wavelengths absorbed and reflected by optic cells. The spectrum of the optic cells lies between red and violet, which is the limit of visible light for humans. Light with a wavelength of 400 nm is perceived as violet, while light with a wavelength of 760 nm is perceived as red. Our eyes cannot see infrared and ultraviolet light. Some animals, however, are known to see light beyond these limits. For example, we know that bees can see certain shades of ultraviolet light, which helps them find flowers to pollenate.

Clearly, it is not an easy job to elaborate on the divine art manifested in such a small area as the retina. Complicated structures and reactions that require specialization even to comprehend keep taking place smoothly every moment we look around. At least we can be thankful for this amazing gift of vision given to us free of charge so that we can recognize the universe.

Notes

[1] It causes the cys form of the molecule to change into the all-trans form. Although the all-trans form has the same chemical structure as the cys form, its chemical structure is different in that it is a flat rather than angular molecule. With the impact of light photons, the position of the molecule in space changes, yet its chemical composition remains the same. Because the position of the reactive regions of all-trans retinal no longer fit in with the reactive regions on scotopsin protein, the molecule is pulled off. The product that forms at that moment is batorhodopsins, which is a partly destroyed combination of all-trans retinal and scotopsin. An extremely unstable compound, batorhodopsin turns into lumirhodopsin in nanoseconds, into metarhodopsin I in microseconds, into metarhodopsin II in about one millisecond, and finally into decomposed products, scotopsin and all-trans retinal much more slowly (in seconds).

[2] The first step in the reformation of rhodopsin is the recycling of all-trans retinal into 11-cys retinal, which requires ATP energy and is catalyzed by retinal isomerase enzyme. Once created, 11-cys retinal combines with scotopsin to form rhodopsin.

Skin is composed of two main interwoven layers of dermis, on the inside, and epidermis, on the outside. The epidermis, which is composed of five sub units, possesses the most important sign of our identity. Each thin layer is arranged in a way to carry out different tasks. A significant amount of elasticity and flexibility is provided to skin via these five layers. These layers can glide on each other slightly and can also be compressed under pressure. They are compressed when we sit on a hard surface. This situation can be similar to the compression of the spring in a click pen, or the suspension of a vehicle under a load. They regain their previous state upon termination of the pressure, like standing up. This elasticity is crucial for skin’s integrity.

The thin construct of our skin contains sweat glands that are embedded in the fibrous connective tissue. There are sensory receptors, hair roots, and hair muscles connected to them, and also loose nerve endings, and a network of capillary vessels. Free nerve endings are created to specialize in various functions so as to sense hot, cold, pressure, and pain. Likewise, the continuation of blood flow relies on very intricate calculations that are hard to explain. When blood vessels arrive at the skin, they are dispersed like a net in the form of capillaries.

The blood pressure of the arteries located at lower section of the skin is higher than the pressure of pulmonary veins. If pressure is applied to skin for a long duration from outside, the pressure in the pulmonary veins builds up and regional blood flow is disrupted. Therefore oxygen, glucose, and other nutritional substances cannot be delivered to these areas; along with inhibition of waste product removal, it leads to a nutritional abnormality in the tissue.

Sensory cells within our skin detect and report nutritional abnormalities of tissue to our brain via various chemical substances (like acetylcholine, bradykinin, and histamine). Thus we change our position consciously or subconsciously with the intervention of our brain to avoid the danger of a nutritional abnormality, and therefore the area regains normal circulation. In this stage, the process is still reversible; however, should the pressure continue, skin cells will start to die from, from the outside in. These systems do work well in healthy persons but in cases of stroke or coma, the intervention system does not work.

This critical picture can be understood better with an example. Just like roads need to be used in order to carry goods and remove trash, the transportation of minerals, vitamins, and many other life saving substances to the distant parts of the body and removal of waste products requires blood vessels to remain open. This must continue in a perfect balance without any interruption throughout our lives.

If a pressure ulcer occurs, it is like being exposed to external dangers in a house if a door or window breaks. It is like a free entrance visa is granted to germs that were blocked. Our back and pointy areas, like, thighs knees, heels, and shoulders are under more pressure, and therefore at more risk when we lie down. Two to six hours of pressure to one of these areas is enough time to disrupt skin integrity. Our daily sleep requirement is around 6-8 hours, therefore we need to switch positions a couple of times during our sleep. Therefore we face this risk everyday in our sleep; however, thanks to the perfectly functioning protective systems, without noticing during our sleep, our position is changed and this dangerous situation is avoided. Intensive care doctors and staff know better what a great blessing that is are since intensive care patients are mostly unable to move. Despite the use of many preventive efforts, like turning the patients in certain periods or the use of air beds, pressure ulcers still occur and a significant portion of patients die of the microbial infections caused by these wounds.

The story of sleepers

“The Seven Sleepers” story in the Christian tradition is retold in the Qur’an as “the People of the Cave.” The story is about a group of young believers who took refuge in a cave fleeing the oppression of the pagan Roman emperor. Both traditions narrate that they fell asleep in the cave, where they stayed asleep for hundreds of years. The Qur’anic account, however, mentions that they were made to change position during their centuries-long sleep: “You would have thought them awake though they were asleep. We caused them to turn over to the right and the left…” (18:18). It is an interesting nuance that they were made to change position, for it sounds rather irrelevant to the rest of the story. However, with the medical conditions of our skin that were explained above, this nuance makes perfect sense as advice to us on how we should treat patients who are unable to move.

In this work we study a verse from the Qur’an, the 47th verse of the Sura al-Dhariyat (The Winds that Scatter), under the light of new discoveries in the field of astrophysics. We note that recent evidence about the accelerating expansion of the universe is also strongly consistent with this verse, although this has shocked the scientific community. In the last part of the article, we discuss possible relations of “metaphysical dimensions” and the concept of “the seven layers” with the word “sama” (translated in to English as “heaven”) as mentioned in the verse.

The existence of the universe is perhaps one of the greatest mysteries in science and philosophy. No convincing argument has been ever put forward that has enabled us to understand this amazing event, not since the beginning of modern science. Religions like Islam, Christianity, and Judaism, on the other hand, explain that the Creator built our robust universe directly out of physical nothingness, independent of any cause. Therefore, the initial creation of such universe would be impossible to explain physically (M. F. Gulen, from his conference on “Evolution and reality”).

In his translation of the relevant verse, S. Yildirim has noted that God keeps the universe expanding and He will continue to do so. Yildirim attributes two meanings to the word musiun in the verse; the first is the owner of great power, strength and wealth; the second is one who expands. Thus, it should not be a surprise to learn that this verse is indeed describing a continually-expanding universe. This might further lead Muslims to think that the Creator has not left the universe unattended after the Big Bang, but rather it is He who has kept creating and expanding it.

In the 1920’s a discovery was made that completely changed our perception of space. It was discovered that distant stars depart from the solar system and leave us even more and more alone in dark space. Then, Fr. Georges-Henri Lemaître, a Belgian astrophysicist, mathematician, and Catholic priest, proposed the idea of the expanding universe. Despite its finite size, it was believed that the universe was expanding.

We can explain this fact simply by an analogy. Think of a toy balloon with spots on it. Mark one of those spots and inflate the balloon. As we inflate it, we observe that all other spots on the surface of the balloon move away from the marked one. So, if we replace the balloon with our universe, the spots will be the stars and planets. If the universe is expanding indeed, then we expect them to be moving away from each other. In other words, the distances between heavenly bodies must be increasing.

Unfortunately, we don’t have a gigantic ruler to measure such immense distances. However, there are other means, such as measuring wave frequencies. Consider the following analogy: Someone throws one ball every second toward a target. Assume that balls travel with constant velocity. If the thrower is stationary, the target will receive one ball every second. However, if the thrower is moving towards the target, it will receive balls more frequently because the balls will be less spaced out. The converse is true if the thrower is moving away from the target. So it is actually the wavelength which is affected; as a consequence, the perceived frequency is also affected. That is, the distances between the waves emitted by objects moving away from us (wavelength) must be increasing, so the frequency decreasing. Likewise, think of an ambulance siren coming towards you and going away from you. It is a good example showing that while an acoustic source that is approaching us emits a higher frequency, the same source radiates lower frequency when going away from us. In physics this is known as the Doppler effect.

Red shift

This phenomenon does not only occur with sound waves, but also with electromagnetic waves. When we think of the spectrum of light, violet at one end has the shortest wavelength and red at the other end has the longest wavelength of visible light. So, any wave of light shifting toward red means the source is moving away from us. It has been determined that the frequency of light emitted by the elements within distant stars shift to a lower frequency, which is called a red shift.

It is this shift that makes astrophysicists think that the universe is expanding. One mustn’t be confused by red shift. This terminology is just used to explain in what direction the frequency is actually shifting on the spectrum. Those signals captured from distant stars have a much smaller frequency (much higher wavelength) than that of red light and they are indeed in the microwave regime and shifting to even much smaller frequency radio waves.

In 2002, an article presenting new evidence of the accelerating expansion of the universe was published by the Royal Astronomical Society. It was not so long ago, only five years, that general opinion concurred with a decelerating expansion. However, the first evidence found by two astronomers in that year led us into a universe that expands in an accelerating fashion, contrary to previous views. This result was absolutely unexpected, because many scientists believed that expansion would slow down due to gravity. Another interesting fact is that if space were to cease expanding, this would be in contradiction to the above verse. God, however, by never allowing this to happen, shows how futile the actions of those who deny His verses are and how extensive His power is, as well as how purposefully He creates.

Dark energy

The groups who worked in the above study figured out, from the brightness of supernovas in distant galaxies, that the universe must expand more and more in the future due to a peculiar dark energy within it. The concept of dark energy was first postulated by Einstein, who named it the “cosmological constant.” However, since this did not fit in well with his theory of general relativity, he withdrew it and said that it was a scientific blunder. Since then, dark energy has had a rather controversial history.

A team of 27 astronomers, directed by Professor Efstathiou of Cambridge University, proposed strong evidence supporting the existence of dark matter, based on completely novel techniques. Their results, which were consistent with previous supernovas, showed that the universe is indeed full of dark matter. Professor Efstathiou thinks that the explanation of dark energy might include additional dimensions like creation (Big Bang) as well. Fr. Lemaître also proposed the expanding universe theory at an opportune time since Edwin Hubble would soon release his red shift observations that strongly supported an expanding universe and, consequently, the Big Bang theory. Here, the Big Bang is seen as the beginning of a continuous expansion.

The verse seems to tell us miraculously that the expansion of the universe will not cease, despite our limited knowledge of the physical reason for its acceleration.

The Hubble Telescope

Another article, published in Nature, presents us the first and deepest picture of space taken by the Hubble Space Telescope. This caused the astronomers to compete in solving the mysteries of the arts of God. The picture, also known as the Hubble Ultra Deep Field, was broadcasted and published in various programs and journals. It has not only shown us the farthest stars of the universe, but the youngest as well. It was very difficult to detect such weak light with the former technology. This picture reveals the embryonic universe, with an age of only 500 million years old. Estimated age of the universe is 13-14 billion years. Three physicists from American Natural History Museum in New York started a competition to publish an article on the Ultra Deep Field picture after the data was disclosed. They hope to answer many questions about the past and future universe. A group at the Stony Brook University, New York, directed by Kenneth Lanzetta, analysed the embryonic samples in the picture to try to discover when various galaxies had been born and how they had evolved. Two other groups are studying the motions of stars and galaxies, as the picture is a result of data collected over a month.

Having looked at the expansion of universe under the light of recent discoveries, now we turn our attention to two other arguments that could be relevant to expansion. Namely, ether (a substance which it is believed fills up the vast universe and which is the ultimate building block of the space), and the seven-layer-universe.

Despite the Michelson-Morley experiment, which argued against theory of luminiferous ether, the propagation of electric, light, or heat in space shows the existence of a substance through which they flow. The Michelson-Morley experiment is nothing more than just a test of the non-existence of certain qualities of ether. For example, in order to show the existence of photons, of which light is made up, we cannot go beyond showing the features of photons. In other words, depending on how we have defined its qualities, we can observe different aspects in the photon, ether, or anything else. In fact, even today, we don’t really know what a photon really is, although we observe its affects every day. In short, it is not possible to show the non-existence of phenomena that cannot be absolutely defined. Instead, we can only test the existence of the properties that we have defined and attributed to them, and thus we better understand their nature of existence in the context of those pre-defined qualities. Hence, the existence of ether is still controversial and needs more thorough research.

Seven layers

Regarding the seven-layer-universe, on the other hand, how is it possible for ether to manifest itself in seven heavens? It may be that these seven layers are not all posed above our heads, but rather that they may be found one with another. The universe is composed of many systems and networks that are the building blocks of their counterparts on larger scales. Each system is governed by laws, which differ slightly from one another. Inside the atom there exists a proton with its unique organization and in a proton we find quarks. For example, communication between protons and electrons is mediated by the electromagnetic force, while the quarks inside the protons communicate via the strong force. These interleaved circles show us that the universe is indeed composed of numerous layers.

We may use these layers for the metaphysical world as well. The human being is not only composed of matter, but also has a mind, a soul, and intelligence. Although these components are accepted as existing by all, their exact nature has not yet been explained by positive sciences.

It seems that the universe is composed of at least two different worlds: The material world (physical) and the immaterial (metaphysical) world. Are these two worlds completely separate, or do they have some features in common? In fact, the existence of humanity might prove to be this common set. But, it may also be true for the universe itself. Nursi states that the distant galaxies, stars and planets are not empty, but home to many spirits and angels who have their own consciences. Thus, one can say that despite the boundaries which separate these two worlds, such as different numbers of temporal and spatial dimensions, they constitute a whole, the Universe. The interaction between them will never fail as long as the universe exists.

The existence of two separate worlds is not that difficult to believe, but there is more:

It is He Who (prepared the earth for your life before He gave you life, and) created all that is in the world for you (in order to create you – the human species – and make the earth suitable for your life); then He directed (His Knowledge, Will, Power, and Favor) to the heaven, and formed it into seven heavens. He has full knowledge of everything. (Baqara 2:29)

The Qur’an calls the heaven where the sun, moon and stars are the lowest heaven or the heaven of the world (Mulk 67:5). The other six heavens may be the heavens of the worlds of the Hereafter.1 We are not sure whether this seven-layer heavens can only be attributed to the physical universe. It might be able to apply to the universe as a whole, with its all seen and unseen layers as well. Even the worlds of angels and spirits may be expanding in accordance with the laws therein, to show how the power and the wealth of God are comprehended in those worlds as well. Although our Earth is finite, the expansion may not be restricted to our finite world, but it may continue in infinite worlds as well.

It is possible that the space being filled with ether has an important role in paving the orbits of planets or stars, as well as other heavenly bodies. We believe that future studies on dark matter, ether, and string theory will help us to better understand the expansion process of the universe.

Note

1. What the Qur’an means by seven heavens has been interpreted in different ways. For further information see Unal, 2006, p. 19.

References

• Ünal, Ali, The Qur’an with Annotated Interpretation in Modern English, The Light, Inc., New Jersey: 2006.
• Monthly Notices of the Royal Astronomical Society, 330, 21 (2002).
• Nursi, S., The Words, The Light, Inc., Istanbul: 2005.

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.

Surely We created humanity of the best pattern. Then We reduced humanity to the lowest of the low, except for those who believe and do good deeds. (95:4-5)

In the following five points, we will explain five out of the thousands of virtues of belief.

First point

Through the light of belief, we reach the highest degree of perfection and become worthy of Paradise. On the other hand, the darkness of unbelief reduces us to the lowest level so that we become worthy of Hell. Belief connects us to our Majestic Maker, and our value derives from using our belief to demonstrate the Divine art and manifest the Divine Names. Unbelief breaks this relation, thereby veiling the Divine art and reducing our value to that of a mere and almost valueless physical entity, for we are no more than a perishable thing, a transient animal. We will explain this truth through a parable.

The value of the iron (or any other material) from which a work of art is made differs from the value of the art expressed in it. Sometimes they may have the same value, or else the art’s worth may be far more valuable than its material or vice versa. An antique may fetch as much as a million dollars, while its material is not even worth a few cents. If taken to the antiques market, it may be sold for its true value because of its art and the brilliant artist’s name. If taken to a blacksmith, it would be sold only for the value of its iron.

Similarly, each of us is a unique, priceless work of God Almighty’s art. We are His Power’s most delicate and graceful miracles, beings created to manifest His Names and inscriptions as miniature specimens of the universe. If we are illuminated with belief, these meaningful inscriptions become visible. Believers manifest them through their connection with their Maker, for the Divine art contained in each individual is revealed through such affirmations as: I am the work of the Majestic Maker, the creature and object of His Mercy and Munificence. As a result, and because we gain value in proportion to how well we reflect this art, we move from insignificance (in material terms) to beings ranked above all creatures. We communicate with God, are His guests on Earth, and are qualified for Paradise.(1)

But if unbelief is ingrained in us, all of the Divine Names’ meaningful manifestations are veiled by darkness and therefore non-expressive. If the artist is unknown, how can the aspects expressing the art’s worth be identified? Thus, most meaningful instances of that sublime art and elevated inscriptions are concealed. In material terms, unbelievers attribute them to trivial causes, nature, and chance, thereby reducing them to plain glass instead of sparkling diamonds. They are no more significant than any other material entity, self-condemned to a transient and suffocating life. They are no better than a most impotent, needy, and afflicted animal that eventually turns to dust. Unbelief thus spoils our nature by changing our diamond into coal.

Second point

Just as belief illuminates us and reveals the messages inscribed in our being by the Eternally-Besought-of-All, so does it illuminate the universe and remove darkness from the past and the future. We will explain this truth through what I experienced regarding the meaning of: God is the Protecting Friend of those who believe. He brings them out of the layers of darkness into the light (2:257).

I saw myself standing on an awe-inspiring bridge set over a deep valley between two mountains. The world was completely covered by a thick darkness. Looking to my right, I imagined I saw a huge tomb. Looking to my left, I felt as if I were seeing violent storms and calamities being prepared amid tremendous waves of darkness. Looking down, I imagined I was seeing a very deep precipice.

In that dreadful darkness, my torch’s dim light revealed a horrifying scene. All along the length of the bridge were such horrible dragons, lions, and monsters that I wished I had no torch. Whichever way I directed it, I got the same fright. This torch brings me only trouble, I exclaimed, angrily casting it to the ground and breaking it. All of a sudden, the darkness was replaced by light, as if I had switched on a huge light by breaking my torch. I saw everything in its true nature.

I discovered that the bridge was a highway on a smooth plain. The huge tomb was a green, beautiful garden in which assemblies of worship, prayer, glorification, and discourse were being led by illustrious persons. The turbulent, stormy, frightening precipices now appeared as a banqueting hall, a shaded promenade, a very beautiful resting place behind lovely mountains. The horrible monsters and dragons were, in fact, camels, sheep, and goats. Praise and thanks be to God for the light of belief, I said, and then awoke reciting: God is the Protecting Friend of those who believe. He brings them out of the layers of darkness into the light.

The two mountains are the beginning and end of this life, and the life between death and Resurrection. The bridge is the lifespan, between the two phases of the past (on the right) and the future (on the left). The torch is our conceited ego that, relying on its own achievements, ignores Divine Revelation. The monsters are the world’s events and extraordinary creatures.

Those who have fallen into the darkness of misguidance and heedlessness because of their confidence in their egos resemble me in the former state”in the dim light of a torch. With their inadequate and misguided knowledge, they see the past as a huge tomb in the darkness of extinction, and the future as a stormy scene of terror controlled by coincidence or chance.

The torch shows them events and creatures. In reality, these are subjugated to the All-Wise and All-Merciful, fulfill specific functions, and serve good purposes in submission to His Decree. However, they see such things as harmful monsters. These are the people referred to in: As to those who do not believe, their protecting friends are false deities. They bring them out of light into layers of darkness (2:257).

But if people are favored with Divine guidance so that belief enters their hearts and their Pharaoh-like egos are broken, enabling them to listen to the Book of God, they will resemble me in my later state. Suddenly the universe will fill with Divine Light, demonstrating the meaning of: God is the light of the heavens and the Earth (24:35).

Through the eye of their hearts, such people see that the past is not a huge tomb; rather, each past century is the realm of authority of a Prophet or a saint, where the purified souls, having completed the duties of their lives (worship) with: God is the Greatest, flew to higher abodes on the side of the future.

Looking to the left and through the light of belief, they discern, behind the mountain-like revolutions of the intermediate world and the next life, a feasting place set up by the All-Compassionate One at palaces of bliss in gardens of Paradise. They understand that such events as storms, earthquakes, and epidemics serve a specific function, just as the spring rain and winds, despite their apparent violence, serve many agreeable purposes. They even see death as the beginning of eternal life, and the grave as the gateway to eternal happiness.

Adapted from Bediuzzaman’s Twenty-third Word, First Chapter.

Footnote

1. For example, prayer is a form of communication with God, who speaks to us through Prophets, inspiration, or Scriptures.