Sometimes, your back itches slightly and scratching it at that perfect spot fills you with an odd sense of happiness. Other times, you notice a biting itch on your arm and a chickpea-like redness shows up there. Oh, those mosquitoes! It is rarely likely to catch a mosquito in the act, and sometimes it even feels as if their bites just appear out of thin air. As you scratch the blister to soothe the itchiness, your eyes scan the room to locate its infamous proboscis. You see it on a wall, plump with the blood it sucked from you. You cannot help thinking: Why do their bites always leave so much itching? Or even, what is the purpose of itching at all?

Itching is an unpleasant feeling we perceive by our skin and mucous membranes, and an occasionally uncomfortable and sometimes very excruciating feeling.

Itching, just like pain, is a sensation intrinsic to our body to protect itself [1].  It is the way our skin “talks” to us. Indeed animals, even fish, itch too. When itched, our skin instinctively and in its own tongue tells us, “There is something that bothers me and I want you to push it away from me immediately!” If it was not for itching, we would not notice a spider walking on our arm. We would not be disturbed by lice and scabies mites or even fungi that settled on our skin, and we would not try to protect ourselves from these pests either.

An ordinary scabies patient has an average number of about 15-20 adult scabies mites on their skin. In the case of Norwegian or crusted scabies, which is most commonly observed among the elderly, the bedridden, people with seriously weakened immune systems, or those who are unable to itch themselves sufficiently, there are thousands of parasites under the thick crusts of the skin [2]. Itching accelerates the blood circulation on the itched parts, and tissues virtually prepare to fight infection by the rushing blood cells and substances [3]. Yet, millions of people also suffer from chronic itching and scratch their itches much more than usual. To understand this, we need to set on a journey from our skin to our brain.

Human skin consists of three layers: epidermis, dermis and subcutis (also known as hypodermis). The dermis layer in the middle makes glove-like protrusions upward into the epidermis. At the top of these protrusions are mechanoreceptors and nerve endings that allow our skin to sense stimulus (such as temperature, sharpness, pressure, vibration, pain, or itching) [3]. With these receptors, our skin functions as one of our five sensory organs and more like an “alarm system” of our body against changing conditions outside. This alarm system has been created so perfectly that each component knows exactly what stimulus to detect.

Previously, it was thought that pain and itching were sensed by the same receptors (nociceptors) and that mild stimuli were responsible for itching while strong stimuli were responsible for pain [4]. Yet, a contradiction existed because while pain triggered an avoidance reflex, itching activated the scratching reflex. In recent years, it was discovered that the receptors (pruriceptors) that perceive the itching sensation on the skin are the free boundary terminations of C-fibers with myelin-free, slow conduction velocity extending in the form of tree branches toward the upper layer of the skin. Furthermore, it was found that the skin cells themselves behave like itch receptors [3, 4]. When we receive a stimulus that induces itching, such as a mosquito bite which leaves anticoagulant substances on our skin, the mast cells in the skin tissue spring to defense against those alien substances. This ensues the secretion of the bodily defense system called mediators, substances that are produced and stored by mast cells as precursor for emergency conditions. Histamine is the most known of these substances and is the most important mediator in itching conditions [5]. Histamine binds to receptors found for itself in myelin-free C fibers that are tasked for detecting itching on the skin. If we consider histamine as a key, the lock that it fits into is on the nerve that senses itching. Thus, the itching nerve is stimulated by histamine.

The nerves receiving this stimulus connect to the spinal cord at their respective levels and transfer the message to another nerve. Each of these transfer processes is mediated neurotransmitters. The last message transmitted to the brain through these nerves is assessed by the brain and labeled as “itching” [6]. The brain determines the coordinates of the itching location and orders the scratching action to the related muscle system. A new journey that conveys messages from the brain to the arm muscles ends with scratching. Considering the swift rubbing action when we feel an ant walking on our face and scratch to push it away, we may value how fast and perfect our brain and transmission system work.

It is also rather odd how soothing itching can be despite its initially uncomfortable feeling, almost as if our body is rewarding us for saving it from a threat. There are several reasons for this contradiction. Scratching causes a low-intensity pain on the skin. Pain and itch are positioned on the skin alternately. The transmission of the sensation of pain is prioritized while the transmission of itching is prevented [7]. Consequently, our brain senses the pain and, in response, secretes the hormone called serotonin to soothe the body. Although this makes us feel relaxed for a short time, the brain continues to transmit virtual sense of itching by connecting to the receptors that are located on the spinal cord along the same nerve path with the receptors for serotonin [8]. This condition, which may be termed as a vicious cycle of itching-scratching, unsurprisingly infuriates patients. Scratching the same area on the skin continuously causes the production of new mediators and oversensitivity of itching nerves, which can thus turn itching into a chronic distress. Chronic itching can often result as a complication from skin diseases such as scabies, lice, eczema, fungal diseases, or drug allergies. It can also result from a systemic disease such as chronic renal failure, cholestatic liver diseases, thyroid problems, iron deficiency anemia, blood diseases and, rarely, cancers [7]. Itching in systemic diseases can be triggered by mediators on the skin but also by neurotransmitters in the intermediate pathway. This kind of itching cannot be controlled by drugs called antihistamines which block the histamine pathway. Sometimes the brain will receive false itching alarms due to post-shingles contraindications or nerve damage in the vertebrae. Such episodes of itching need to be addressed to prevent adverse outcomes. At times, the reason an itch can occur can even be psychological when there seems to be no need for an itch. According to research, scratching activates the brain’s reward center which triggers the addiction mechanism. Patients in that case are thrilled as they itch constantly [9].

As doors in this mysterious journey of science are opened one after another, we discover that nothing has been created without a purpose, including apparently discomforting sensations such as itching, which, it turns out, is how our skin communicates with us!

References

1. Arıcan O. Kasintinin patofizyolojisi, klinigi ve tedavisi Turkderm 2005;39(2):88-97
2. Jonston G, Sladden M. 2005 Scabies: diagnosis and treatment BMJ;17;331(7517):619-22
3. Guyton AC, Hall JE. Tıbbi Fizyoloji 10. Baski 2001.p815-42
4. Schmelz M. Itch and pain. Neurosci Biobehav Rev 2010;34(2):171-6
5. Arck P, Raus R. From the Brain-skin connection. Neuroimmunomodulation 2006;13(5-6)347-56
6. Metz M, Stander S. Chronic pruritus pathogenesis clinical aspects and treatment. J Eur Acad Dermatol Veneral 2010;24(11)1249-60
7. Metz M, Grundman S, Stander S. Pruritus: an overview of current concepts. Vet Dermatol 2011;22(2):121-31
8. Chen ZF et all. Descending control of itching transmission by Serotonergic System via 5-HT1A-facilitated GRP-GRPR signaling. Neuron Vol.84(4) Nov.19-2014

9. Chan YH et all. Brain’s Reward Circuits Mediate Itch Relief. A functional MRI Study of Active Scratching. Dec. 2013

“There was a footpath leading across the fields to New Southgate, and I used to go there alone to watch the sunset and contemplate suicide. I did not, however, commit suicide, because I wished to know more about mathematics.”
-Bertrand Russell, Nobel Laureate and Mathematician

It is mystical when you step outside on a snowy morning. Snowflakes are swirling around the vast sky and falling and blanketing the ground. If a snowflake lands on you, it is like a winter angel. There are no flowers around, for they cannot survive the cold; yet what lies before your eyes is an incredible beauty. And it’s remarkable, you come to realize, that no two snowflakes are alike. It is as if the uniqueness of a snowflake is controlled by a divine force. The individuality of a snowflake’s structure draws a parallel to human life. Like snowflakes, everyone has a unique story to tell.

I am not the only one who ponders about snowflakes; many mathematicians do the same. Actually, they think about the characteristics of snowflakes because they are particularly important for three basic mathematical principles: pattern, symmetry, and symmetry breaking.

A little-known scientist, Wilson Bentley, a.k.a. “the Snowflake Man” took pictures of snowflakes almost every day and observed them until he died. You can buy his book about his work on Amazon. If you wish to know why he did it, read about it at snowflakebentley.com.

“Under the microscope, I found that snowflakes were miracles of nature; and it seemed a shame that this beauty should not be seen and appreciated by others. Every crystal was a masterpiece of design and no one design was ever repeated. When a snowflake melted, that design was forever lost. That beauty was gone, without leaving any record behind.”
-Wilson Bentley

When I checked the Oxford dictionary, there were 3 definitions for the word “pattern.” Two of these definitions [listed below] are important for this article.

Pattern: 1. A repeated decorative design; 2. An example for others to follow.

When we check the pictures and delve deeper into each snowflake, we will see that the structures of the snowflakes are totally different. However, they have something in common: symmetry and a hexagonal structure.

These perfect ice crystals are genuine, even though it is hard to believe they are not fake.

When I take a close look at a snowflake, the beauty of the combination of ice molecules fascinates me every time; each flake is unique. However, uniqueness is not the point here. The things that make snowflakes important objects for mathematicians are their symmetry and their hexagonal structure. Math-loving people have a lot of interest in transformations. They love moving objects. And, surprisingly, if an object is symmetric, transformations are not even noticed by many.

To be more precise, when you have a hexagonal symmetric snowflake, or any other symmetrical object, when you rotate it in any direction, 60°, 120°, 180°, 240°, 300°, or 360°, people watching you wouldn’t realize it. If you check the images below, you will see rotated shapes but no difference. It appears to be the same shape in exactly the same place.

1- Counterclockwise rotation by 120°

2- Reflection through a vertical axis

3- Reflection axes of a snowflake[1]

Snowflakes also possess reflectional symmetry. If we stand in front of a mirror, our reflection looks exactly the same. Hence, if we put a mirror in the middle of a snowflake, there will be a reflection. For a snowflake, we can put a mirror 6 different ways. Thus, we can say that a snowflake has 12 symmetries: 6 from reflections, and 6 from rotations.[2]

Now we can define symmetry as a transformation that leaves things unchanged. We can also claim that a combination of any of the transformations will give us exactly the same shape. For instance, we can rotate our snowflake 60° two or three times in a row and flip it over, and it will remain unchanged.

At this point, you might ask the question: “You have all these fancy symmetries for this particular snowflake. But, does every snowflake possess the same symmetries?”

Snow is a molecular structure of an ice crystal. And ice is a structured substance. It is a different form of water. When the water cools down, the molecules move more slowly, and this begins to impact how the molecules line up. Hydrogen atoms of one water molecule bond with two oxygen atoms. As the water freezes, the molecules arrange into hexagonal patterns. They prefer to stay as far away from each other as possible, and that makes them take up more space. The large space affects density. The density of ice becomes less dense than water. This is why ice floats. Almost all other liquids have a higher density when they freeze.

When we examine an ice crystal carefully under normal conditions, we always see a combination of molecules with six-fold symmetry. Snowflake molecules make a honeycomb structure. This results in an inordinate amount of hexagonal symmetry in these molecular three-dimensional structures.

Okay, we saw the structure of a snowflake under normal conditions. But, what if we changed those conditions? Johannes Kepler answered this question after his experiments and wrote a book about snowflakes, particularly The Six-Cornered Snowflake.

There are two key elements which affect the structure of a snowflake: temperature and moisture. Each time the temperature or the amount of moisture change, the structure of a snowflake changes. If you check the snow crystal morphology diagram below, you will see that when the temperature nears 0° and humidity is high, the structure of a snowflake will be flowery. Flowery structures are called dendrites. When you make it a little bit colder, the structure will be fancy hexagonal plates. We can apply many combinations and get varying structures.

The Snow Crystal Morphology Diagram. Source: Snow Crystals – http://www.snowcrystals.com/science/science.html

Professor of physics Kenneth G. Libbrecht is the owner of the diagram below. In a PBS interview, he said, “It’s a mystery as to why snowflake shapes go from plates to columns to plates to columns as the temperature lowers. That’s one of the things I’ve been trying to understand. It has been a mystery for about 75 years, and it’s still unsolved.”[3]

The Shapes of Snowflakes | Source

In the end, although the structure of (almost) all snowflakes are the same, some of them are not completely hexagonal. For instance, there are some snowflakes that have tree structures. Some snowflakes have branches, and each branch has tiny branches.

But, why is the structure of some snowflakes not hexagonal?

So far, we have talked about pictures which were taken at a particular instant. We have seen the pictures of the motion of the snowflakes for the smallest amount of time that can be measured. However, a snowflake never stops spinning in the air. They tend to oscillate. That means the shape of the snowflake is changing all the time. But how? When you see a snowflake in the air, it changes its place after a second because it would be whirled about, and it will be under different conditions at that time. This process will occur up until the snowflake lands on the ground. We know from the diagram that the temperature and amount of moisture always affect the shape of a snowflake. While small-scale conditions are almost the same, on a larger-time scale, conditions will differ. And these differences will change every corner of a hexagonal snowflake, resulting in a different structure. This is the main reason behind the variety of snowflake structures and uniqueness.

In conclusion, we can say that a snowflake can preserve its six-fold symmetry at all times. I think we have another reason to love mathematics! I want to finish my piece with Hermann Hankel’s words:

“In most sciences one generation tears down what another has built, and what one has established another undoes. In mathematics alone, each generation adds a new story to the old structure.”

he debate over religion’s role in social change has been raging for centuries.

The interpretation and perception of even just a single social action is multi-layered, multi-faceted, complex, and sophisticated. It almost seems impossible to explain a social action entirely through any of our sciences; in fact, it seems unlikely that any science will be developed that fully encompasses all of humanity’s problems.

As human beings our needs, conscious or unconscious, stretch from a tiny atomic particle to nearly the whole universe. It sometimes seems that the whole universe and all that within it are not good enough to satisfy even the smallest need of our unlimited desire. Some have asserted that one day human beings are going to play the role of God. They do this because of their strong and persistent belief that we are merely the product of material existence and it is therefore the material realm that makes us who we are. As such, they believe we will eventually rule over the things that created us.

Others would undoubtedly take a whole different direction and argue that our nature is a complex, interwoven tapestry of the material and immaterial realms; it is imprecise to contend that it is only economic conditions or conditioning that beget all the other elements of our social and individual lives, which includes things such as literature, the fine arts, religion, and the like. Hence, I intend to examine the notions of two influential intellectuals of the recent past: Karl Marx and Max Weber, particularly their notions as to religion.

To begin with, the history of humanity has seen a lot of wars, but the intellectual war that we have experienced over the past two centuries, which split the entire world into two blocks of countries (until recently they were communist and capitalist), should be of the greatest interest to almost everyone; it has been a one-of-a-kind struggle.

Marx, a reductionist, framed his argument as such:

“…the history of all hitherto existing society is the history of class struggle. Freeman and slave, patrician and plebeian, lord and serf, guild-master and journeyman, in a single word, oppressor and oppressed, stood in constant opposition to one another, carried on uninterrupted, now hidden, now open fight, a fight that each time ended, either in revolutionary re-constitution of society at large, or in the common ruin of the contending classes.”

He wrote this about the sorry state of the working class, especially in the nineteenth century, when workers were treated almost like machines or animals. This was particularly true in Western Europe. Even from just these few lines, one could easily grasp the sympathy of Marx for the working class of his time, what he called the oppressed, and his animosity and utter disgust toward the elite class, what he called the oppressor. It is no surprise then to see him portray a system in which the rights of the oppressed to a happy life could not be realized as needing to be overthrown through a social upheaval or revolution against the oppressors. For Marx, everything was crystal clear: it was the economic system which made the elites oppress their workers (please see “Karl Marx: the Prophet of Materialism” article in this issue).

Marx frequently turned to the then recent revolutions occurring in Western Europe: the English Civil War of the 1600s and the French Revolution. These struggles cost many lives and were for him just a new chapter in the ever-repeating class struggle between the oppressor and the oppressed.

On the surface, the apparent causes of the infamous conflict could be identified as politics and religion, which were quite intertwined then. A thorough analysis of Marx’s society enabled him to discover the subtle connection between the social class divisions and the stages of economic development, and allowed him to postulate his version of human salvation: communism, in which the superstructure, with all its elements including religion, would perish eternally in the name of a utopian, classless society. He prophesied a future in which the communal life of people would be shaped by a new idealized economic system that negated all private ownership of property, monopolized the political structure, and left no room for religion in social and individual life. As a matter of fact, most of his writings reflect his reactive response to the perceived evils or fatal flaws of capitalism. For instance, while some people enjoyed luxurious lives because of the fact that they were born to a rich family, many others endured the severest conditions just to survive. Witnessing this, one cannot help but wonder, “Is the economic system to be blamed for this?” Or even, “Are the ill-perception, misuse, and exploitation of the system the culprit?” I am completely sure that every sensible human being would appreciate the diagnosis of the diseases of class struggle and the oppression of the poor, but I also think it is hasty to reflexively blame the system – capitalism – as being solely to blame for the wretched conditions of the oppressed. According to Marx, religion was the opiate fed by the oppressors to the oppressed to keep them in line. To realize the revolution that Marx felt was necessary, this opiate had to be eliminated.

His approach to religion was always contemptuous and very similar to the functional and reductionist theories of Freud and Durkheim. In his view, religion is nothing more than a pure illusion – in other words, an entity that has no real existence. Therefore, he did not heed what religious beliefs or holy books taught; rather, he emphasized the function that religion and its fundamental elements played in social life. Even though his portrayal of religion was reduced to a social function, he still maintained that we should discover why people insist on this illusion, arguably since the beginning of human life.

As depicted above, Marx left no room for religion in his imagined world after the envisaged revolution against the oppressor. He saw it as an effect, an expression or a symptom of a deeper reality: material facts of the class struggle and alienation. Religion was the culprit to be annihilated in the name of real human bliss.

On the other hand, almost a half century later, a young and bright social scientist would dare to hold a completely different account of religion and argue that though the economic conditions of an individual or a society could determine the tone of some religious beliefs or practices, history would bear witness otherwise. He stated:

“…the side of the problem which is generally most difficult to grasp: the influence of certain religious ideas on the development of an economic spirit, or the ethos of an economic system. In this case we are dealing with the connection of the spirit of the modern economic life with the rational ethics of ascetic Protestantism. Thus we treat here only one side of the causal chain.”

In “The Protestant Ethic and the Spirit of Capitalism,” Max Weber diligently outlined a delicate connection between an attitudinal and doctrinal change in the framework of a religious group of Protestantism and the economic development that followed. Throughout his scholarly treatise, he gave an exquisitely drawn picture of the early Protestants, particularly the pioneers of Protestantism: Martin Luther and John Calvin. In fact, he claimed that the self-constraining ethic of Protestantism that stemmed from the inner-worldly asceticism fostered with frugality, personal discipline, solemnity, thrift, self-denial, hard work, investment, and making the best use of one’s time and resources was the spirit of capitalism. There was, he explained, a sharp difference between the adherents of the then Catholic Church, which regarded the daily chores and business enterprises as petty issues compared to the religious works of monks, nuns, and priests (other-worldly asceticism), and the followers of early Protestantism, who praised any effort to please God, including daily chores and especially the acquisition of wealth (inner-world asceticism).

He aptly placed this sharp change of attitude in the disciples of Calvin towards the acquisition of wealth at the very center of the eventual rise of the capitalist economy and the birth of a new civilization. Some monumental maxims like, “A penny saved is a penny earned…”, “Time is money; sloth is sin…”; “Even the humblest tasks are solemn duties assigned by God Himself…”; “All work, not just religious work, was a calling from God; it should not be done but done well, as a faithful service carried out under the great Taskmaster’s eye…” reflect this spirit of capitalism in Protestant countries like the United States and England. For Weber, “an idea in the mind of one human agent (or shared by a group of agents) is as much a real cause of human action as the application of heat to water is the real cause of steam.” Therefore, the backbone of the current capitalism originates in the very change in the belief system of a group of religious people. Such a claim is a consistent proof for social scientists like Weber to argue against the extremely reductionist notions of religion like that of Marx.

The two contrasting views of religion are significantly worth studying. While Marx, with his infamous animosity towards religion, divorced it from his utopian communist society and sentenced it to death forever, he adamantly upheld the necessities of human nature and pointed out the fact that negligence of the material aspect of life would result in absurdities in the name of human salvation. Moreover, his emphasis that history had become an arena of social class struggle urged humans to find lasting resolutions in order to establish projections of heavenly bliss on earth. Humanity undoubtedly owes him a round of applause due to his incessant efforts to vocalize the rights of the oppressed to life, dignity, and freedom. However, it is truly heartbreaking to see that he could not apprehend the real core of religion, which is pure devotion, compassion, self-denial, and other humble traits. If only he had chosen a different path that appreciated the diverse nature of humanity, of which religion is a distinguished component. I have never understood why Marx negated the fact that as material conditions shape ideas, ideas also cause material beings to change. Hence, unlike Marx, Weber approved of the fact that the key cause of the capitalist revolution was not some material circumstance, but a new form of economic behavior that followed logically from a new religious idea: “the self-constraining ethic of Protestantism was the animating spirit of capitalism.”

Has the battle come to an end yet? Honestly, I would assert it is an ongoing process. As we progress in light of the more inspiring notions of contemporary social scientists, we come to realize how wrong it is to reduce a very deeply embedded part of human social and individual life -religion- to something superficial or hypothetical. It is rather to be understood as something “sui generis” and a multi-faceted reality – a reality in and of itself. It is unquestionably inspiring to see several people search for an answer to what religion is and at the same time quite overwhelming to know that a great number of things in religion need an unbiased, pure, and sophisticated mind supported with the sublime emotions or faculties of the (metaphorical) heart. Furthermore, it is absolutely necessary to devise a new, multicolored approach to religious studies that embrace not only the fine-tuned minds but also the purified hearts. It would be wise to heed Kant’s argument against pure reason: “The ultimate truth can never be known through the theoretical mind. Only then can it be perceived partially via the practical mind.” Finally, it wouldn’t be a mere exaggeration to assert that what religion is or what role it plays in social and individual lives is a question of life and death to a certain degree. Hence, is religion a cause, an effect – or both? While many would say it is just an effect, several others would sail to the shore of “a cause”; still others, like me, agree that religion is both, and that every thought or emotion should get the benefit of the doubt.

References

1. Anatomy of the Sacred, an introduction to religion, 5th Ed. by James C. Livingston
2. Introducing Religion, readings from the classic theorist, by Daniel L. Pals
3. Eight Theories of Religion, 2nd Ed., by Daniel L. Pals
4. Gale Encyclopedia of Religion, 2nd Ed.
5. Encyclopedia of Quran by Jane Dammen McAuliffe

How can we then speak of absolute justice when there are so many innocents oppressed, murdered, and their rights confiscated at the hands of tyrants? “Is God just” Dr. Horkuc asks in this issue when He creates people in their respective particular places and under particular conditions and expect the same scores from both? Horkuc writes in this issue that the cup analogy of Bediuzzaman offers a solution to this dilemma.

Occupied with extreme work load, a great majority of us in modern times are bent double and exhausted in most cases to the point of total collapse. Is it only the amount of unnecessary work load or that we do not know how to deal with the present conditions that underlies this exhaustion? Ihsan Kose argues for a “minimum work principle” in the universe. From gravity to routes ants pursue on their tracks, to electrical circuit boards, the path light moves and all phenomena in the universe apparently manifest themselves with one common thing: lowest energy consumption. The article is prescriptive in the sense that whatever we may be busy with, we can and we should find the most efficient formula for best outcome in return for minimum amount of energy, so that we can make best of our stamina reserves.

Computer games are approached with suspicion, yet the number of people engaging with games and the amount of hours and even days we spend for them are increasing. “Gamification,” however, Ahmet Tugra argues, has become a trendy word. “It aims at transforming real life context in a manner that adopts game thinking in online platforms. From this perspective, it proposes to increase motivation, engagement, sense of enjoyment, and the positive attitudes of people towards work.” Games enhance cognitive development in children, and a balanced adaptation of games into real life contexts may help us generate more convenient work and family environment for adults.

The minimum work principle is the force used on deeper levels (the maximum economy principle in other words). According to this, every action in the book of the universe is completed in a fashion to cause minimal energy consumption in the present binding conditions. The term binding condition refers to conditions that are mandatory (forced) for the system here. For instance, the total energy of a gas in a container that is perfectly insulated from the external environment is constant and therefore when we are investigating this gas, we should not overlook the conservation of total energy as a binding condition. Therefore, even for tiny actions, from the swing of a tree leaf with the wind to the flight of a dust particle in the air, the lowest energy consumption is essential in terms of present binding conditions.

We can make the topic easier to understand via short cut events of circuit boards. The reason behind a short cut is the conduction of electrical charges by the route with the least consumed energy. If even multiple short cuts are designed to attract electrical charges in an electrical circuitry, these charges are conducted via the route that requires the lowest energy.

It is all right, but how do electrical charges know this route? It is possible to ask a similar question about the orbit a ball follows when we throw it forward in a horizontal direction. The thrown ball continues on the orbit with the lowest amount of energy consumption depending on the present binding conditions (such as wind direction, strength, and the ball’s geometry). This is all well and good, but how does the ball know it will exert more energy on another trajectory?

Light follows the path where it moves fastest in the environment. In physics, “Fermat’s principle” states that when light is passing from one environment to another, it will be refracted not in the shortest path, but in the fastest direction of travel in the new environment (Figure 2). Therefore Fermat’s principle is the projection of the minimum energy principle on optics. In other words, the least amount of energy is spent by light on the path in which it will move fastest. However, for light to determine the direction that will be fastest, does it not have to first display refraction in all angles to identify the fastest path?

For science historian James Gleick it is impossible for physicists to discuss the minimum energy principle without giving the ball some type of willpower; the ball seems to choose its own orbit, as if it has knowledge of all the possibilities ahead of time.

A nice example in the living world for the minimum work principle is the similarity of ant behavior to the maximum economy principle. When some groups of the ant colony set out to forage, they communicate with pheromone hormones amongst each other. An ant that has found food leaves pheromones on the ground – indicating the quantity and quality of food – to guide others.

Another ant that follows this pheromone trace reaches the food, and marks the surface on the path back to nest with the pheromone by assessing the amount and quantity. Pheromones in spots that are not renewed by the ants within a certain time frame evaporate. Upon investigation of the ant routes, they are always found to follow the shortest path in between the food and nest, and leave pheromone tracks accordingly. For instance, when an asymmetric obstacle is positioned on the ant route (Figure 1), ants after a certain time are able to locate the shortest route again.

However, a more interesting case is the movement of the ant species named Wasmannia auropunctata when they are passing from one environment to another (Figure 3). It’s based on Fermat’s principle.

Not only ants, but also humans display trends that follow Fermat’s principle. For example, an emergency worker trying to rescue a drowning swimmer adheres to the most suitable strategy to reach the person at sea: When the beach and sea are considered as two different environments, first the rescuer runs to the nearest point to the swimmer on the beach, then reaches swimmer by entering the sea. Since humans move at different speeds on sand and at sea, if rescuer tried to reach the swimmer by entering directly into sea, it would take longer to reach the swimmer.

As seen in the above principle, the natural order of the world is created with incredible wisdom, without wasting any energy. Each truth has different projections on each existence and event. However, this distance in between the events or existences feels very far to us, therefore it is necessary to look more carefully to notice this relation among different projections.

There are also projections of this minimum work principle in our personal lives too. During the position of prostration in prayer, which can be considered as the humblest state of being when one feels closest to the Divine, the head, the highest point of body, is brought down to the level of the feet to compose a potentially lower energy status. This, in terms of the physical sciences, is the situation with the lowest work achievement capability, and can be seen as a status in which human deficiency and weakness as opposed to the infinite power of the Almighty are declared.

The minimal work principle can also be adopted in shaping the methods and style of providing services to other people, especially in the service of faith. Humans are the sons of their ages. Each age can be defined as a different environment. Therefore, when humans interpret their experiences, the socio-cultural environment where one is born and the specifics of their period must be considered. The shortest cut to people’s hearts and minds with minimal work principle is possible when the conditions of the time are taken into consideration. Said Nursi once said if he were to live in the time of Rumi (13th century), he would have written the Mathnawi, rather than his magnum opus the Risale-i Nur, and Rumi would do the same if he lived during his time. The Mathnawi eight centuries ago was and the Risale-i Nur today is the safest, shortest, and widest public avenue of faith and reflected the zeitgeist of their respective periods in history, Nursi argued.

References

1. James Gleick, Genius, Richard Feynman and Modern Physics, Abacus, London, 1993.
2. Jan Oettler, Volker S. Schmid, Niko Zankl, Olivier Rey, Andreas Dress, Jurgen Heinze, Fermat’s Principle of Least Time Predicts Refraction of Ant Trails at Substrate Borders, PLoS ONE 8(3): e59739. doi:10.1371/journal.pone.0059739

Carbon atom, which composes nearly 0.2% of the earth’s crust, has a very special place among elements. All living beings are formed from carbon-based compounds. In addition, 94% percent of compounds—that is, more than 4 million—contain carbon atoms. Certain carbon compounds form nearly 18% of the matter in living beings. The rest is mostly water. These compounds are used as building blocks in cell formation. Only carbon has the ability of compounding with other elements in sufficient variety and complexities in order to carry out the main functions that life is based on. As carbon atoms easily form chains by making chemical bonds, no other element is given such a quality. These chains formed in a line can separate into branches and can connect to form rings. These rings are actually polygons formed by three, four, five, six, or more carbon atoms. Due to this quality, carbon is the element that forms the basis of many things from the foods we eat, to the clothes we wear, from the fuels we use, to the furniture we have.

The heat level that makes carbon compounds possible is between -20 and +120 0C. Carbon compounds begin freezing at -20 0C and they begin breaking at 120 0C. In space, where extreme heat and freezing cold exists, the only heat range that makes carbon compounds possible is found on earth and this is a very sensitive heat range. Temperatures in our neighboring planets give a better idea: as hot as 450 0C in Venus, and as cold as -53 0C in Mars. Under these temperatures, it is impossible for carbon element to form compounds and thus living beings. Therefore, the earth is the only planet created with the suitable conditions that make life possible.

Crystal structures of carbon atom

Particular repeating arrangement of atoms in three dimensional space to form a certain geometric shape is known as a crystal structure.

Different crystal structures of the same substance are named “allotrope.” Carbon has three different allotropes found in nature: amorphous carbon (coal), graphite, diamond. In addition to these, an artificially produced allotrope is fullerene.

Amorphous carbon (coal)

Amorphous structure is one without a definite crystal structure; that is, one where atoms take their places in free order. A mass of carbon atoms of amorphous structure is known as coal. After plants die, they undergo chemical transformation with the activities of microorganisms. If dead plants collect in a suitable wetland and are buried into the ground with a geological process, the carbon amount in their body increases and they begin transforming into coal. Types of coal are categorized according to the carbon percentage they contain. Geologically, this transformation process takes a period of 15 to 345 million years. Coal is one of the most commonly used forms of energy.

Graphite

In graphite, carbon atoms are found in a hexagonal crystal structure. These sheets, resembling the surface of a honeycomb, pile up and form graphite. As the sheets are not connected with firm bonds, they easily shift when some force is applied. This is why graphite is used for eliminating friction at machine industry. The black substance in pencils is graphite hardened by adding some clay. Graphite can resist very high temperatures. Therefore it is used within the steel industry and melting metals. In addition, it is a very good conductor of electricity. For this reason, the brushes of the electric engines in household machines such as a washing machine and a vacuum cleaner are made of graphite. In recent years, graphite has been used as heat shields of space shuttles.

Diamond

Diamond is the hardest natural substance we know. In spite of being a transparent substance and having no color of its own, it can be found in pastel colors such as yellow, brown, or even dim black, owing to being mixed with other minerals. Diamond is a perfect electric isolator and is the substance with highest heat conductivity. For this reason, it can be cut without being deformed. In diamond, carbon atoms are found in a pattern to form a cubical crystal structure. Extraordinary resistance of carbon-carbon bond and its hard and integrated structure prevents its reacting with other things around. It burns at a heat of 850 0C. In a piece of diamond, there can be other atoms that cause impurity and decrease the value. In good quality natural diamonds, there is only 1 alien atom versus 100,000 carbon atoms. In addition to jewelry, diamonds are widely used at industrial products such as drills, glass cutters and the like. 75-80 % of diamond production is used in this industry.

Formation of coal, graphite, or diamond from carbon

Carbon based organic compounds were buried underground as a result of movements by the earth’s crust millions of years ago. Physical and chemical changes occurred with those organic masses through heat and pressure. Gradually, water, carbon dioxide, oxygen, and—in the highest phases—hydrogen leaves these masses. This organic matter called “turba” (first transforms into lignite, then to sub bituminous coal, then to bituminous coal, and then to anthracite). If the conditions allow, it transforms into graphite. Coal is the first type of substance formed by carbon atoms on their journey to become diamond. As lower values of heat, pressure, and time suffice for coal formation, graphite requires much higher values. Diamond is formed in the mantle layer of the earth at about 150-200 depth. This valuable substance is later carried to the surface of the earth by volcanic rocks such as lamproite and kimberlite. In order for diamond to form, an atmospheric pressure of 50,000 atm, 2,400 0C of heat, and a period of 3 billion years are required. Without this immense pressure and long time, the substance to be formed by carbon will simply be graphite. It is possible to transform graphite into diamond artificially; however, according to calculations, a minimum pressure of 10,000 atm is required. In 1955, for the first time artificial diamond was obtained under 100,000 atm, 2,500 0C heat, and by using chrome as catalyzer. However, the pieces of diamond obtained were small and black, most of them did not classify as jewels. In another attempt made in 1962, graphite turned into diamond under 200,000 atm, 5,000 0C heat, without using any catalyzer.

The similarity between carbon and human beings

As carbon atoms’ properties change according to the crystal structure, people’s lifestyle and view of life depends on the community they live in and their position in that community. In order to become diamond, the highest level of its kind, a person needs to undergo hard conditions. If carbon atoms were to say, “this is more than we can bear, we prefer easier conditions,” then they can be nothing more than graphite. If the conditions for graphite are avoided as well, then one cannot go beyond the level of coal. Diamonds are kept in safes and worn in most important occasions and graphite has different kinds of practical use as an industrial material. As for coal, it ends up in fire. The situation of human beings in a way resembles carbon atoms. Every person is made of the same elements biologically. Their value will naturally be different, according to the processes they underwent and the behaviors they presented. Some show patience in the face of misfortune, put their sincere trust in God, and become the diamonds of humanity. Some others, whom we can compare to graphite, attain a desirable level even if they cannot become diamonds. Those who choose to assume the lowliest form are likely to face a similar fate with the coal.

References

• H. W. Kroto, J. R. Heath, S. C. O’Brien, R. F. Curl ve R. E. Smalley. 1985. “C60: Buckminsterfullerene.” Nature 318. DOI:10.1038/318162a0.
• L. Vlasov, D. Trifonov. 2005. 107 Stories about Chemistry, TUBÝTAK., Ankara.

After he began to call his people to belief, the Prophet had to face all kinds of torment during his peaceful mission for thirteen years in Mecca. After numerous grievous incidents, he had to leave his town and reluctantly immigrated to Medina. From most people’s point of view, the Meccans were absolutely to be declared as “the enemy”-or “the other.” However, the Prophet did not behave inimical to anyone. He always treated people humanely, no matter what lethal traps they set for him. He never failed to extend his tender hand with a candid clemency and compassion. Even during many inexorable combats, he always prayed to his Lord, chiefly for those who smashed his helmet off, broke his tooth, and left his face covered with blood in battles like Badr and Uhud. Not only did he hinder his followers from bearing any oppugnant attitude against their merciless foes, he also blocked maledictions and imprecations to any adversary, even those who, for instance on the day of Uhud, had ripped the bodies of nearly 70 beloved ones into pieces beyond recognition with an incredible brutality.

Although his opponents were bloodthirsty and yearning for war, his sword was never besmeared by red hot blood; he never killed anyone. He did not represent anything other than loving compassion in the world.

He never broke off his previous social connections. He did not approach anyone with a bias. He always held the door open in order to mildly flatter their vanities. He never hurt anyone’s pride deliberately. While his sworn enemies took the gloves off for any opportunity to assassinate him, he treated everyone amicably by taking into consideration the potential positions they would likely to hold in the near future. Because he knew that every individual had a respectable essence, he thought the most appropriate action was to awaken this divine kernel. He took action in this direction, though horrid provocations did not cease, and he did that with a worthy perseverance.

Glad tidings

The Prophet dealt with every one of his opponents with utmost care, and he took very strategic measures not to destroy them but to conquer their hearts.

Giving the glad tidings of a coming peace, the following verse was revealed right after the Battle of the Trench:

(When you obey God in His commands and prohibitions,) it may be that God will bring about love and friendship between you and those of them with whom you are in enmity. God is All-Powerful, and God is All-Forgiving, All-Compassionate. (60:7)

Peace was so close, just at their threshold. Having received this good news, the Prophet initiated immediate action by demanding to marry the daughter of Abu Sufyan, who was then the political leader of the Meccans. Establishing bonds of kinship with him would be a plausible step in order to eradicate hostility. Umm Habiba, Abu Sufyan’s daughter, was among the group of Muslims who had fled the Meccan torture and sought refuge in Ethiopia. However, her husband died there, and she was left alone with her child without any protection. By marrying her, the Prophet would not only save this devoted Muslim woman from despair and honor her, but would also form a connection with Abu Sufyan that would not be possible by any other way. This marriage was realized soon, and afterwards everything changed dramatically.

Abu Sufyan, who was one of the staunch enemies of the Prophet until that day, could easily enter the Prophet’s home to visit Umm Habiba, his daughter. Now, Abu Sufyan could learn more about Islam through his daughter Umm Habiba. He began to realize soon that Muslims were not as he had believed. In a short period of time, the difference in Abu Sufyan’s attitude became more and more obvious. He turned out to be more moderate, more cautious, and more candid in reciprocal dialogue attempts.

Prominent figures of Mecca, Khalid ibn al-Walid, Safwan ibn-i Umayya, Suhayl ibn Amr and Ikrima ibn al-Jahl were exerting pressure on Abu Sufyan to take drastic actions against believers. Despite all of their intolerable pressure, Abu Sufyan resisted their aggressiveness, having realized that they were the ones who were unfair, not those on the Prophet’s side.

Making peace

Even in the most critical conditions he did not give up. Despite all the provocations of evil-doers and his own fellow tribesmen’s objections, he made agreements with his crucial adversaries and fulfilled peaceful commitments with them.

The radical change of Abu Sufyan was an explicit hope for others. The Prophet tried his best to take advantage of every single opportunity to get in touch with any of them.

After his immigration to Medina, the economic and social conditions of Mecca had gradually deteriorated. The Meccans were suffering from drought, famine, hunger, and misery. For sure, he could not have remained indifferent to this heart-rending situation. He sent them food and other needed aid; he literally inundated them with an immense benevolent contribution on the back of hundreds of camels. But, unfortunately the Meccans rejected all of it. Then he sent all the aid directly to Abu Sufyan. Afterwards Abu Sufyan distributed everything to the poor and needy Meccans.

The Prophet those days gave weight to free commerce and trading with other communities, particularly with Meccans. He knew that business trading was an excellent opportunity to get in touch with others. Thus they could have found so many new ways to maintain peaceful relations.

Regrettably, all the peaceful attempts made by God’s Holy Messenger were either repelled or responded to with brutal violence by the Meccans. They once attacked a Muslim tribe in the pitch dark of midnight and slaughtered 23 civilians in a village near Medina. By committing this crime, the Meccans also violated the Hudaybiya peace treaty.

Following this brutal attack, the Messenger of God sent envoys to Mecca, offering them various options to solve the problem peacefully, rather than an immediate retaliation: he asked them to pay the blood money and cut their relations with other warring tribes that participated in this crime. Failing to obey these conditions would mean the Hudaybiya treaty was violated as well as a declaration of war. But the Meccans refused every amicable offer. The only option left for the Prophet was to march to Mecca. Realizing that they would not be able to resist, some of the eminent Meccans fled in confusion to distant towns of the Arab Sahara. God’s Messenger sent someone in pursuit of every missing Meccan. Umm Haqim, Ikrima’s wife, who had fled all the way to Yemen, went after him. She dared all dangers on the way to find her husband, another relentless enemy of the Prophet and the son of Abu Jahl, and to introduce him to the Prophet’s mercy. Umayr ibn Wahb, once a hitman hired by Safwan ibn Umayya to kill the Prophet, went after Safwan twice, reaching him in Jeddah en route to Ethiopia, and convinced to him to return to Mecca. Suhayl ibn Amr was brought back by Abdullah, his own son whom he tortured for years. He wrote letter after letter to Wahshi, who had murdered Hamza, the Prophet’s uncle, and invited Hind, who had hired Wahshi for this murder, to come in peace and that she was forgiven. The Prophet called them back home promising to forgive all their past assaults and guaranteed their protection. Mecca became a land of peace and serenity, thanks to his efforts and merciful invitation.

The Prophet’s immense forgiveness is an example for us today as to how we should engage with past atrocities. It is a message of self-reformation that teaches us that we can subdue feelings of revenge and hatred and build a society in compassion and love.

Fatih Harpci is a PhD candidate at the Temple University, Department of Religion, Philadelphia.

‘Peaceful coexistence is the most important project of our era. But we cannot do it alone or in isolation; we must do it together.’

The world has become very small.

Mass communications, mass travel, and economic interdependence have created a contemporary world in which we as individuals and groups no longer can live in isolation from other groups as well as we could have in previous periods. Nations and groups of people who barely knew of each other now see each other’s lives and worlds in living color and in real time through television and the internet. Governments who counted on secrecy and submission just a few years ago now find themselves humbled, bewildered, and even overthrown through mass communications that broadcast their tyrannical deeds—and the bravery of those who resist them—to the entire world. Regions who thrived in their own prosperity in isolation from the poverty and stagnation of other regions now find their economies racked by volatility as globalism ties the purse strings of world commerce together into complicated knots.

The world has become small, and we are with each other—knowing of, affecting, and interacting with each other—more than we ever have in the history of the world. And we are not the same. Yes, we are all human beings. Yes, all of us are subject to the universal conditions of human existence like uncertainty, change, loss, and death. But how we deal with those conditions and what we make them mean depends in large part on our distinctive cultures, backgrounds, languages, and histories. Herein lie the differences in the human family. We do not think the same. We don’t pray to the same gods. We don’t choose the same cultural values. We don’t share specific histories. We interpret the world, and ourselves in it, in very different ways.

Given these differences, how can we all live together? Is peaceful coexistence possible globally, regionally, or even within one family? If so, what are the necessary components that create it? In other words, what are the preconditions—philosophically, socially, politically, culturally, or otherwise—for peaceful coexistence among different people? These are powerful and complex questions that require asking even more questions in order to answer.

First we must ask questions of history.

Have we as human beings ever lived together peacefully? Have people of very different faiths, for example, ever lived with each other for a sustained period of time without seeking to oppress or eradicate each other? Answering these questions requires a significant and thorough study of world history.

If we determine that sustained peaceful coexistence has been achieved in certain situations—for example, under the Ottomans in the fifteenth century, or in thirteenth-century Spain—we must further determine what factors allowed that coexistence to occur. What were the specific conditions—economic, political, social, cultural, etc.—that made that coexistence possible? These conditions and factors are myriad; to distinguish them so that they can be meaningful to us today requires intensive analysis from highly skilled and knowledgeable individuals.

Once distinguished, can the conditions that made peaceful coexistence possible elsewhere and in a different era be transported to the present time, into a current situation of conflict and violence? Can the conditions be recreated today, the present time, although taken from the past? This may seem simple, but it is not. People change from era to era. Notions of what is permissible, moral, and just change over time even within one culture, much more across cultures. What worked in a previous period, in terms of a conception of societal harmony and justice, cannot simply be picked up and moved into a new era with different notions of morality, truth, society, etc. Things must be translated first, and even before being translated, we must determine if the factors in question can be translated at all. Worldviews may have changed so much in the intervening centuries that they no longer work as viable concepts for today.

If certain conditions and factors that generate peaceful coexistence can be translated from the past into today’s world, they must then be implemented socially, culturally, politically, economically, and legally. In many instances, this will require a fundamental overhaul of current socio-political systems. Transformations of this nature are daunting simply because of their sheer magnitude. Moreover, such societal transformations contain within them the seeds for violence and injustice. They rarely happen without conflict. Implementation of new societal structures must happen in a way that minimizes or omits opportunities for breakdown, violence, and retribution from those who may feel left out or trampled upon by the changes. Otherwise, the implementation of a new system for peaceful coexistence ends up perpetuating yet more violent conflict.

These are the questions we must ask of history. But we cannot stop there. We must also ask questions of the religions.

What is the general stance of our religious traditions to those who do not share its beliefs and commitments? Does it demand eradication of all contrary belief systems and the people who propagate them? Or does it request accommodation of ‘the stranger,’ or those who believe and live differently? In short, do people of faith ground themselves into patterns of tolerance or intolerance as they root themselves in their faith traditions?

These are difficult questions to answer because the religions themselves, as historical entities that grow and change over time, sometimes seem to have multiple ways of being with regard to peaceful coexistence. Over the centuries, adherents of the largest two religions in the world—Christianity and Islam—have lived both peacefully and non-peacefully with each other, and with people of other religions they encountered. Certainly, the teachings of both religions encourage peaceful coexistence in their respective sacred texts and traditions. However, both these religions also have suffered violent expression in the hands of those who either ignore the teachings of coexistence, or twist the teachings to justify violence and terror.

Whatever our religious traditions were intended to be, the fact is that historically they have been used to perpetrate some of the worst imaginable violence ever created in the human family. And we have to face this hard fact with courage, and with resolve to enlist our religious traditions as major players in the project of peaceful coexistence.

The potential for religious conflict in society is the chief reason why societies that have achieved peaceful coexistence to any extent champion religious tolerance as a chief civic virtue, and they actually implement that virtue into society culturally and legally. Given the diverse and absolute claims of many religious and moral traditions, tolerance is really all we can ask of people. We cannot, in a truly pluralistic society, expect morally committed or devout persons to embrace or to celebrate practices that they, due to their faith or ethics, consider to be sinful, heretical, or abhorrent. We cannot expect them to acknowledge the legitimacy of gods, or modes of worship, or ways of life they consider to be false. To expect this in the realm of religion is to be fundamentally intolerant. We cannot advocate, in the name of tolerance, a society that tolerates everything but certain forms of traditional religious or moral conviction.

Tolerance, then, is the capacity to put up with or to accommodate ideas, beliefs, and behaviors that one finds deeply problematic, and is society’s most essential civic virtue, especially in societies as ethnically, religiously, and racially diverse as many countries are becoming in this period of globalization. Daily life in such societies simply will not move along if the citizenry cannot practice basic tolerance. Of course, simply gritting our teeth and grudgingly putting up with others we don’t like or with whom we disagree is the low-water mark of societal growth. Ideally, we would grow to a place of greater understanding and appreciation for those who are radically different from us, even if we still do not accept or agree with their beliefs or practices. Sometimes, however, basic tolerance, especially in matters of religion, is the best we can do.

These are the questions we must ask of our religions. But we cannot stop here, either. We must also ask questions of ourselves.

We must search ourselves and examine our hearts. Are we really committed to living together with people who are different from us? Do we really accept the fact that we as people will never all believe, think, pray, live, or act the same—and that we just have to deal with it? Or do we resent these ‘facts on the ground’ and spend our efforts trying to coerce others or force them into changing to be more like us? Or, having given up on making other people like us, do we isolate ourselves into enclaves of sameness and construct the daily arc of our lives so that we don’t have to encounter many people who are different from us?

Part of the reason why achieving peaceful coexistence is so challenging has to do with individuals. All the legal, cultural, and societal structures that support peaceful coexistence may be in place; however, they will fail to show results unless one thing is true—people genuinely must want to live in peace. This is not a given. While we may think, and commonly say, that all people really want is to live in peace, this is not true. Not everyone wants to live in peace. Often people put qualifiers to the prospects for peace in their lives and worlds. For example, they say, ‘I want peace in my region, but not if it means giving up any of our land.’ Or, ‘I want peace in the region, but we cannot allow attacks on our national honor.’ In other words, we say we want peace, but not if it means we have to give up something that we deem more important than peace. Many of us value other things more than peace.

Even in our personal lives, in our relationships with family and friends, we often keep grudges and enmities in place for years and years despite many opportunities to do away with them and create peace. Why? Because we would have to give up something that we value more than peace, in order to achieve peace in that situation—a feeling of being right, a sense of superiority, the perverse joy we take in condemning other people or groups, and other things. We have to let go of these types of things to create peace, yet we often prefer them to peace. So, the conflict and tension endure year after year, and all the while we are saying, to ourselves and to others, that we want peace. We are not being honest about the situation. We value other things more than peace.

Ultimately, achieving peaceful coexistence at the individual, interpersonal level has to do with a person’s capacity for difference. How comfortable are we with people who are different from us? Do we feel threatened by them? Do we feel nervous around them? Or, can we be relaxed and comfortable within ourselves even when surrounded by people who believe, look, and act differently than us? Today’s global world demands all of us to expand our inner capacities for difference, so that we are not easily threatened by people who are not exactly like us. All of us must stretch our comfort zones beyond their current boundaries.

These are the hard, searching questions we must ask ourselves.

Only when we give ourselves authentically to these questions with a view toward creating sustained, peaceful coexistence will we have a future worth living for. Moreover, all of us must do this work together—religious and secular, liberals and conservatives—all of us. Otherwise, the forces of globalization that have made our world smaller will bring with it new and more barbaric forms of hatred, oppression, and violence.

Achieving peaceful coexistence is, then, the most important project of our era. And we must give ourselves to it wholly, with our fullest capacities for knowledge and understanding, with our truest intentions for truth and justice, and with our bravest strengths in order to journey through the challenges and difficulties that the process entails. We most certainly can do it. But we cannot do it alone or in isolation; we must do it together.

In this issue the article on “The Adaptation in the Senses” points to the fact that the human body is blessed with an ability to adapt to the surrounding conditions by way of which our senses get used to changing climate, light, and even pain. This feature of our body is a mercy, considering that if we could not adapt to circumstances, life would be torture. Could this be the reason bombings and civilian sufferings in Iraq do not irritate me-because I have been watching or reading about it for more than five years now and my senses are adapted to being exposed to the same play on the Iraqi stage?

While voicing a strong longing for the lofty and colorful life of centuries ago, the lead article is a consolation for the victims of all times as it reminds the reader of how joyous enthusiasm was once achieved: “We believed as long as we could employ our willpower up to its potential all problems could be overcome as a result of divine help. We always managed to discover contentment in our soul and proceeded on our course.” In such a state of psychology no misfortune can shake any individual or community.

In this issue you will meet Ottoman Women: Myth and Reality, a book which won the Benjamin Franklin best book in history award in May 2008. Its description of the legal rights and social status of Muslim women in the nineteenth century will shatter life-long prejudices about harem life. Another writer, Dr Salik, takes us on a space journey to discover planets orbiting other stars where scientists hope to test theories developed on planet creation. Thomas C. Smedley offers an interesting pattern of engaging with foreign cultures as a result of his personal experiences with the Turkish community in the USA. Smedley says that by practicing role reversal, a person of good will can overcome the barriers of language, religion, and nationality.

Ramadan mubarak! We wish this holy month of Islam may be a means of peace and joy for all peoples of the world.

For a long time astronomers have talked about the nine planets orbiting the Sun. These nine heavenly bodies have always been more special than other objects orbiting the Sun, such as asteroids and comets. The nine planets are larger than others; you can see some of them in the sky even with the naked eye if you know where to look. In September 2003, astronomer Mike Brown of Caltech and his colleagues announced the discovery of a new object in the sky, then named 2003 UB313 Eris, which is 27% larger than Pluto. This made astronomers reconsider the definition of a planet, thereby making Pluto and Eris two of the new category of objects orbiting the Sun dubbed “dwarf planets.”

While astronomers are engaged in the debate on planet definitions, astrophysicists still have not agreed about how planets were created. In fact, the journal Science recently put the birth of planets on the list of the top 125 questions scientists will tackle in the next quarter century.1 The comment ended with: “Planetary systems around other stars should provide clues.”

The reason scientists are interested in extrasolar planets- planets orbiting other stars, or exoplanets in short- is not limited to their curiosity about how planets were created. The second major motive for exoplanet research is the attempt to detect another “habitable” planet. NASA’s Origins Program,2 for example, is attempting to answer the question, “Are there worlds like the Earth around nearby stars? If so, are they habitable, and is life as we know it present there?” This is one of the major questions the new field of astrobiology is striving to answer.

In this article, we give an overview of planets and exoplanets with an emphasis on the critical conditions for life on a planet.

Planets and Exoplanets

The International Astronomical Union’s 2006 definition of a planet states that a planet is a celestial body that (1) is in orbit around a star, (2) has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round shape) but is not itself a star, and (3) has “cleared the neighborhood” around its orbit.

According to this definition, Pluto is indeed not a planet as its “moon” Charon is half the size of Pluto, whereas the moons of all other planets are much smaller than their respective parent planets. In addition, Pluto’s orbit is not as “clean” as the orbits of other planets.

Having introduced the new planet definition, we want to emphasize the first and foremost condition: a planet has to be in orbit around a star-not around the Sun. According to NASA Jet Propulsion Lab’s PlanetQuest website, as of August 2007, about 250 exoplanets in 99 planetary systems have been discovered. (The site exoplanets.org gives 228 planets around nearby stars.)

Discovery of solar planets is not too challenging: you take a clear picture of the same portion of the sky periodically, and compare the successive pictures. If you see an object that changes its position, then you can be sure that it is an object orbiting the Sun. Because stars are very far away compared to bodies orbiting the Sun, they seem stationary relative to us.

To give a sense of how far the stars are from us, think of the nearest star, Proxima Centauri, which is 4.3 light years away. One light year is the distance light travels in one year, which is 5.88 million million miles. If you fly a supersonic jet-a jet that can break the sound barrier (765 mph), such as the SR-713 or the MiG-25R, which can reach three times the speed of sound in the air-you would have to fly for about 1 million years nonstop to arrive at the nearest star. The most distant planet, Uranus, is about 0.002 million million miles away from the Sun, which is more than 12,000 times closer than Proxima Centauri-your trip to Uranus with a supersonic jet will take only about 80 years.

Exoplanets are as far away as stars. Therefore, it is impossible to detect them using the simple picture-the-sky method utilized for the solar planets. Every star with planets in its orbit is affected by the mass of the planets. This causes the star to sway back and forth. With extremely sensitive instruments measuring the Doppler shift in the frequency of light received from the star, the effect of the planet on the star can be detected.4 Another method is called astrometry: precise measurement of the positions of the stars relative to very distant stars, which appear stationary because they are far away. Small movements of the star because of the presence of planets can be detected.5

Direct optical detection of exoplanets is extremely hard, as they do not give off their own light. In the presence of the bright star, the planet becomes totally invisible. There are a few solutions. In the transit method, a planet blocks some of the star’s light as it transits past the star.6 Sensitive instruments can detect such small dips in the brightness of the stars. Also, interferometric detection7 can be used to detect the extremely weak light from the planet. Another optical detection method is called the “choronograph,” which is used to physically block the glare of the parent star, exposing the planet.

How are planets created?

The motion of a planet around the Sun can be described using two conservation laws-conservation of energy and conservation of angular momentum. Based on the understanding of orbital mechanics and the well-known laws of motion (first published in their entirety by Newton), it has become routine to place satellites in orbit around different planets to conduct various studies. Although science has been quite successful in describing planetary motion, we still do not know how planets were created. The conservation laws mentioned above do not determine the number, orbits, rotation directions, sizes, or type-rocky or gas giant-of planets. Initial conditions play a significant role; initial mass distribution around the star, the size of the particles orbiting the star during the early stages of the star’s life, and the initial orbits of these particles-when considered with the laws of motion, conservation laws, and the law of gravitational attraction-result in different planet-creation scenarios.

There are currently two main theories of planet creation, the gravitational instability and core accretion theories. In the gravitational instability theory, planets form during a rapid collapse of a dense cloud. In the core accretion theory, planets start as small rock-ice cores that grow as they gravitationally acquire additional mass.8 By detecting planets recently created around different stars, scientists hope to test these theories.

Search for life on exoplanets

Diverse life forms on the Earth are taken for granted. The average individual does not think much about the inner workings of life and the conditions that make life possible on the Earth.

Earth is a rocky planet that contains heavier elements, such as silicon, iron, and so on. We know that heavier elements were created during the supernova explosions,9 which comprised a few generations of stars, and therefore more than a few billion years. In a galaxy that is very young, one does not expect there will have been enough supernova explosions to produce heavy elements.

In an old galaxy, however, one does not expect to see radioactive elements. Thus, the planets that form in an old galaxy might be as dead as the moon because there will not be enough radioactive fuel. The Milky Way, our galaxy, is neither very young nor very old. Note that ages of galaxies and stars are in the order of billions of years-our sun is estimated to have been created about 4.6 billion years ago, and it is a middle–aged star.

In the Milky Way, our sun is placed at just the right spot, about halfway from the center.10 At the core of our galaxy, the density of stars is so high that they collide with each other. At the outer extremities, at the rim of the galaxy, the star density is too low to generate the heavier elements that make up planets as very few supernova explosions are expected.11

The orbits of all planets are elliptical, but very close to being circles. This is very significant for a planet if life is to prosper. Eccentricity is a measure of the elliptical shape of an orbit. A perfect circular orbit has an eccentricity of 0 (zero), and as the eccentricity comes closer to 1, the orbit becomes like a sausage. The earth’s orbit around the sun has an eccentricity of 0.067, very close to a perfect circle. If the eccentricity were to become 0.3, the average global temperature would become 73 F (23 C), compared with 58 F (14.5 C) on the Earth now, and, “some parts of the African, South American and Australian interiors heat up to 140 F (60 C)” when the Earth passes closest to the Sun,” according to Darren Williams and his colleagues of Pennsylvania State University.12 On an orbit with eccentricity of 0.4, the average temperature would increase to 86 F (30 C). Given the current scientific opinion on global warming and how catastrophic conditions could become because of a few degrees increase due to increasing amount of carbon dioxide in the atmosphere, you can imagine how unbearable the Earth would become for many complex life forms. Therefore, for a planet to bear life on its surface, its orbit must be at an optimum range of distances from the parent star, which is dubbed the “habitable zone.”

All planetary orbits around the Sun-not only that of the Earth-are nearly circular, and they do not cross each other’s orbits. If there were a number of planets with highly eccentric orbits around the Sun, some of them would cross the Earth’s orbit increasing the probability of a collision.

Obviously, a planet with life as we know it on Earth would need to be a rocky planet. In the solar system only four planets (Mercury, Venus, Earth, and Mars) are rocky planets; the other four (Jupiter, Saturn, Uranus, and Neptune) are gas giants.

The existence of gas giants, Jupiter being the largest of all, appears to be very important, too. Meteorite collision is a likely Doomsday scenario for the inhabitants of the Earth. In fact, meteorite collisions are cited as the main cause of the extinction of many species from the face of Earth in its several billion-year history.13 Jupiter is about 5au away from the Sun-1au is the mean Earth–Sun distance, nearly 150 million km-and as the most massive planet it plays a critical role in protecting the Earth from meteorites and comets.

In addition to all these astronomical conditions, the Earth has a magnetic belt that protects it from charged particles ejected from the Sun and other bodies. The Earth has an atmosphere,14 and the presence of water is absolutely critical for life.15

Of the almost three hundred exoplanets so far identified, most of them are gas giants as massive as Jupiter-more than 300 Earth masses. Therefore, scientists do not expect a glimpse of life on them. Recently, Christophe Lovis of the University of Geneva and his colleagues reported three low-mass planets orbiting the nearby star HD 69830, described as “hot-Neptunes” or “super-Earths”, as their masses are from 5–20 times the mass of the Earth. Scientists predict that two of these planets may be rocky planets based on theoretical calculations.16 For more conclusive results, however, telescopes with much higher resolutions are needed. Such telescopes are expected to be operational within a decade.

In conclusion, research interest in exoplanets originates from questions about the mechanism of planet creation, and the attempt to find planets where life can exist as we experience it on our blue planet. We do not know whether we will be able locate other worlds similar to the Earth with their own inhabitants. One thing we know, however, is that life is only possible through a great many critical conditions acting together in stars and planets as well as in cells and molecules. Life is very special indeed. Although the existence of other planetary systems suggests that our solar system is not as unique as once thought, with its “blue” planet -a planet that can support biological life-it still seems absolutely unique. Many scientists think, however, that with better tools and methods it is only a matter of time before we locate an Earth-like exoplanet. Time will prove or disprove their predictions.

Dr. Ertan Salik is an Assistant Prof. of Physics at California State Polytechnic Univ, Pomona. As well as teaching and conducting physics research Dr. Salik is currently involved in many education programs.

Notes

1. Science, Vol. 309, No. 5731, pp. 1–204 (2005).

2. NASA Origins program: http://origins.jpl.nasa.gov and http://origins.stsci.edu/

3. http://www.sr-71.org/ Accessed 2008-07-26.

4. Struve, Otto. “Proposal for a project of high-precision stellar radial velocity work”, The Observatory 72 (1952): 199–200, http://en.wikipedia.org/wiki/Doppler_spectroscopy Accessed 2008-07-26.

5. http://www.planetary.org/explore/topics/extrasolar_planets/extrasolar/astrometry.html Accessed 2008-07-26.

6. Charbonneau, D.; T. Brown; A. Burrows; G. Laughlin (2006). “When Extraslar Planets Transit Their Parent Stars”. Protostars and Planets V, University of Arizona Press.

7. Exoplanet detection using a nulling interferometer, Manuel P. Cagigal and Vidal F. Canales, Optics Express, Vol. 9, No. 1, 2 July 2001.

8. http://planetquest.jpl.nasa.gov/news/giantRockyCore.cfm Accessed 2008-07-26.

9. Gedik, Nuh. “Supernova Explosions and a Miracle of The Qur’an,” The Fountain, April-June 2006.

10. Weed, William Speed. “Circles of Life,” Discovery, November 2002.

11. See Charbonneau 2006.

12. Weed, 2002.

13. Gonullu, Omer Said. “The Message of Meteorites,” The Fountain, January–March 2005.

14. Cakmak, Osman. “A Journey in the Atmosphere,” The Fountain, January–March 2002.

15. Gedik, Nuh. “The Miracles of Water,” The Fountain, January–March 2005.

16. Lovis, Christophe et al. Nature, 441, 305–309 (18 May 2006).