Smart prosthetic hand combines both human and robot control

Zhuang et al. Shared human–robot proportional control of a dexterous myoelectric prosthesis. Nature Machine Intelligence, September 2019.

Holding an object in your hand might seem easy, but it’s actually a very complicated and challenging task; if, for instance, an object starts to slip, you typically have a couple of milliseconds to react. Scientists have been trying new approaches for improved control of robotic hands, particularly for use by amputees. A recent technology was able to combine individual finger control and automation for improved grasping and manipulation by successfully merging the fields of neuroengineering and robotics. This interdisciplinary approach was tested on three amputees and seven non-amputee subjects. The neuroengineers achieved the intended finger movement from muscular activity on the amputee’s stump, allowing for individual finger control of a prosthetic hand, which had never been done before. The robotics team enabled the robotic hand to take hold of objects and maintain contact with them for robust grasping. The amputee first performed a series of hand movements in order to train the algorithm through a machine learning paradigm. This taught the algorithm to decode user intention and translate it into finger movements of the prosthetic hand. Concurrently, sensors placed on the amputee’s stump detected muscular activity, which trained the algorithm to learn which hand movements corresponded to which patterns of muscular activity. Once the user’s intended finger movements were acquired, this information could then be used to control individual fingers on the prosthetic hand. When the user tried to grasp an object, the robotic automation initiated. The algorithm told the prosthetic hand to close its fingers when an object was in contact with sensors on the hand’s surface. This automatic grasping was designed to infer the shape of objects and grasp them based on tactile information alone, without any help of visual signals. The robotic hand has the ability to react within 400 milliseconds, and it is equipped with pressure sensors all along the fingers: it can react and stabilize the object before the brain can actually perceive that the object is slipping. While this promising technology can be used in in several neuro-prosthetic applications such as bionic hand prostheses and brain-to-machine interfaces, there are still many challenges remaining to implement this technology in a commercially available prosthetic hand for amputees. It is currently being tested and improved.

Cats securely bond with people, too

Vitale et al. Attachment bonds between domestic cats and humans. Current Biology, September 2019.

Dogs have long been regarded as man’s best friend. They’re sociable, faithful, and obedient. Cats, on the other hand, are often described as more aloof, mysterious, and independent. But a new study suggests that cats actually bond with their owners in similar ways to how humans and dogs bond with companions. The most established way to study human attachment behavior is to observe an infant’s response to a reunion with their caregiver following a brief absence in a novel environment. When a caregiver returns, secure infants quickly return to relaxed exploration while insecure individuals engage in excessive clinging or avoidance behavior. These tests had been previously run with humans, primates, and dogs; researchers decided to run the same test with cats. 79 kittens and 38 adult cats and their caregivers were recruited. During the test, an adult cat or kitten spent two minutes in a novel room with their caregiver followed by two minutes alone. Then, they had a two-minute reunion. The cats’ responses to seeing their owners again were classified into attachment styles. The results show that cats bond in a way that’s surprisingly similar to infants. In humans, 65% of infants are securely attached to their caregiver and domestic cats and kittens mirrored this, as about 65% of them securely bonded to their people. After the first round of tests, the researchers enrolled half the kittens used in the study in a training and socialization course. The other half served as a control group. Researchers then found the same results, suggesting the training did not have an effect on kittens’ attachment behavior toward their owners. This indicates that once a cat forms a bond, it seems to remain stable over time. This social flexibility may have helped facilitate the success of the species in human homes. It is still not clear what the factors are that shape the caretaker relationship, but it’s likely a miraculous complex mix of genetics, personality, and experience.

An efficient and green way to convert heat into electricity

Zheng et al. Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe. Science Advances, September 2019.

A recent discovery could help scientists to develop more efficient ways to generate electricity from heat that would have been otherwise wasted, such as heat coming from car exhaust, industrial processes, and interplanetary space probes. In principle, magnetic fields can be used to generate electricity. If we move a magnet through a coil or wire, the magnet pushes and pulls electrons that create an electrical current. Magnets themselves don’t have energy, but they can control energy currents through the created magnetic field. The main problem with magnets is that when a magnet is heated up, it loses most of its magnetic properties and becomes a so-called paramagnet. Until this discovery, scientists believed that paramagnets couldn’t be used for generating electricity. In the new study, researchers found a way of designing thermoelectric semiconductors that can convert heat to electricity. The tiny particles in paramagnets, so called paramagnons, ended up producing enough spin to push an electron, for only a billionth of a millionth of a second – apparently long enough to make paramagnets viable energy-harvesters. This breakthrough in the conventional understanding of magnetic properties could lead to more research into how magnets and energy interact to potentially facilitate electricity production from heat that is otherwise wasted and oftentimes harmful to the environment.

Observing Majorana fermions in the ferromagnetic atomic chains on a superconductor. Nadj-Perge et al. Science, October 2014.

In the universe, matter and antimatter particles are always produced as a pair and, if they come in contact, they destroy each other in a flash of energy. In 1937, an Italian theoretical physicist named Ettore Majorana had proposed that there can be unique exceptions to this rule: a stable particle could exist in nature that is both matter and antimatter. Scientists have been looking for that indefinable particle, also known as the “Majorana fermion,” for seventy years. A group of researchers recently reported that they were able to detect the Majorana particle which behaves simultaneously like matter and antimatter. Researchers designed an experimental system allowing them to observe an emergent particle inside a material. They first generated an extended chain of pre magnetic iron atoms on a superconductor made of lead. Then, they cooled the material to -272 C, just about one point above absolute zero, and monitored it using a giant two-story-tall scanning-tunneling microscope, which can track electrical signal changes with very high precision. Finally, they were able to capture a glowing image of an electrically neutral particle at the ends of atomically thin iron wires. The Majorana particle was surprisingly stable and the opposing properties make the particle neutral so that it interacts very weakly with its environment. The discovery of the Majorana particle has exciting implications for several areas of modern physics, engineering, and astrophysics. For example, Majorana particles are very similar to neutrinos, as they both have very weak interactions with the matter. Neutrinos are thought to make up most of the dark matter that fill the Cosmos. Perhaps, neutrinos are simply Majorana-like particles and Majorana particles are also a candidate for what dark matter is. As an industrial application, Majorana particles can be utilized in quantum computing which aims to create computers to handle incalculable systems. The current quantum computing technology uses electrons, but they are known to be very unstable due to high interaction rates with surrounding materials. However, since Majorana particles are neutral and highly stable, they can be engineered into a variety of materials to produce more reliable and powerful quantum computing applications.

The Bitter Side of Artificial Sweeteners

Artificial sweeteners induce glucose intolerance by altering the gut’s microbiota. Suez J. et al. Nature, September 2014.

There have been conflicting and confusing findings about the health effects of artificial sweeteners over the past several decades. Some studies found that they cause weight loss and others found the exact opposite. Some studies linked them to diabetes and other studies argued otherwise. A recent study provided a series of experimental evidences that artificial sweeteners disrupt the body’s ability to regulate blood sugar, and thus may cause metabolic diseases and diabetes. Researchers, using animal models and human studies, found that sweeteners significantly alter the gut’s microbiome – the collective name of bacterial colonies living in our intestines. The composition of our gut microflora plays a critical role protecting us from pathogenic bacteria, the metabolism of indigestible components of our diet, and modulating development and regulation of the immune system. Sweeteners – in the form of saccharin, sucralose, or aspartame – are found to alter the mix of microbes in our intestines and consequently change how our bodies metabolize glucose. Constant use of sweeteners in mice and human test groups caused typical glucose intolerance symptoms in which glucose levels rose higher after eating and declined more slowly than expected. Glucose intolerance can ultimately lead to serious illnesses like metabolic syndrome and Type 2 diabetes. Although this study will cause a lot of discussions and headaches in the food industry, the link identified between microbiome and glucose intolerance will definitely inspire novel therapeutic approaches to metabolic disorders such as diabetes.

Brainy Fingertips

Edge-orientation processing in first-order tactile neurons. Pruszynski JA and Johansson RS. Nature Neuroscience, August 2014

A new study found that neurons in human skin are able to perform advanced calculations that scientists thought only the brain was capable of performing. A group of sensory neurons that extend into the skin and record touch are called first-order neurons in the tactile system. Each nerve ending branches in the skin to form about 5mm2 elliptical receptive field, with up to 8 highly sensitive zones that are unevenly distributed within the field. It turns out that these neurons not only transmit information about when and how intensely an object is touched to the brain, but they also send complex information about the touched object’s shape. Researchers found that the sensitivity of individual neurons to the shape of an object depends on the layout of the neuron’s highly-sensitive zones in the skin. Computations that require untangling geometric shape information are classified as feature extraction computations in neuroscience and are typically attributed to the immensely complex circuits of the cerebral cortex. This study showed that neuronal populations localized outside of the brain, such as first-order tactile neurons, can have advanced processing capacity similar to brain neurons. These results can also potentially improve treatments for nerve injury and rehabilitation, as scientists previously assumed that the cerebral cortex was doing all the work.

“I am an aerodynamicist. I ask myself, by subscribing to aerodynamicism and providing mechanical explanations devoid of conscience, am I committing a murder against air? What if the air’s motion is the embodiment of conscious acts with feelings?”

Have you ever thought of the mechanics of a murder? Yes, the mechanics of a murder! Given an object with 50 grams of mass at point A, with a velocity of 400 m/s, the time it takes to reach point B, which is 4 meters away, is approximately 10 milliseconds. When this mass reaches point B, it contacts a surface that can sustain a maximum of 90 m/s2 acceleration. Because the momentum of the 50 gram object is high enough to overcome this limit, it penetrates this surface. As it cuts through the target object, its kinetic energy is converted to heat. Eventually, the 50 gram object comes to a stop, but the path it has opened now becomes filled with a red-colored, non-Newtonian fluid whose density is 1060 kg/m3 and whose viscosity is 3.5 x 10-3 Pa.s. When this fluid flow stops due to a process called agglutination, or commonly known as clotting, the whole system achieves a steady-state behavior, i.e. all motions come to a halt.

“All motions come to a halt”: that is death. This explanation could be the murder of your parent who was assassinated while working for the good of your country, or your family members who were martyred during a war. And this scientific picture made of dead words cannot portray the love and sorrow gushing out of your eyes. But I can tell you where your love and sorrow can be found.

Loving means being vulnerable, and you know why? Because when you love someone, their presence stimulates the release of dopamine in your brain. Dopamine is the hormone that lowers the threshold of feeling pleasure and pain, thus you feel pleased and hurt more easily. Your emotional devastation is nothing but an accumulation of dopamine in your brain. Just wait until it diffuses completely. As the common wisdom says: time heals everything.

Loving also means bonding, and you know why? Because when you love someone, their presence stimulates the release of oxytocin in your body. Oxytocin is the hormone that accompanies the feeling of serenity while with your loved one. It also functions in pair bonding and fidelity. The terror in your mind and the brokenness in your soul in the aftermath of your loss is only a hunger for oxytocin.

What did you say? My explanations would not console you? See a psychiatrist and take some pills to balance your hormone levels. Don’t worry. Everything is going to be all right.

That’s Enough!

I cannot take it anymore. I can’t go on with my life when one side of my being is tortured by the other. Did you, too, feel tormented by the explanations I just told you? These words are coming from the cold chamber of science, where all emotions are to be kept dead-frozen. Isn’t it a murder in itself?

I am an aerodynamicist. Calling myself an aerodynamicist recalls an ideology that hasn’t been named, that doesn’t exist in encyclopedias: aerodynamicism. Aerodynamicism has its own dogmas, rules, methods. It tells you that air is just another fluid whose behavior can be studied through mathematics and experiments. So, I ask myself, by subscribing to aerodynamicism and providing mechanical explanations devoid of conscience, am I committing a murder against air? What if the air’s motion is the embodiment of conscious acts with feelings?

Perhaps I should listen to the air itself, instead of what others say about it. Maybe I should at least give air a chance to show me that it is actually alive, that it has emotions. So I stand atop a hill overlooking a bay. I keep silent, and try to remove the scientific knowledge that is clogging my ears. And I start hearing something:

It is the wind. As the air approaches my body, it slows down, forms a stationary layer right around my torso. Around this layer, it paces gradually towards my back. Behind my arms, it forms small vortices that are shed along with the wind. What I am hearing is actually the sound of the friction between my ear and the air. And the whistling sound is the vortex-shedding triggered by the separation of the air’s flow from the body’s surface. Hey, hey, hey… I thought I was listening to the air! This is not air! This is my self, forging mechanical shapes and passing them off as if they belong to air. If air has feelings, it must be very disappointed by my hypocritical pose of listening. I just invited it into my lungs for an intimate conversation, but I aborted that conversation with my scientific thoughts.

I should apologize. With my eyes closed and arms wide open, I allow my whole being to be embraced by air. “I am sorry. I hope I did not hurt your feelings. Are you crying?”

“Crying only ends with the act of shedding tears, but it starts long before when someone hurts the love inherent in creation. I am crying. I want to shed my tears, each like a galaxy, to the expanse of the universe till the end of time. Isn’t there someone out there to hear me?”

“Why do you feel so alone?”

“I feel alone because I am different. Although I visit many people and many places every day, it is a very routine interaction going on between me and everything else: mundane tasks to be performed without intimacy. Like the two parties in a business. Once the mutual interests are delivered, the relationship is over. No loyalty, no love. I imagine myself like a chunk of meat going through a meat grinder. This is a meaningless, merciless flow where your identity or existence means nothing special. So, why would I talk to those people about my private world anyway? Instead, just a few words about the weather…”

“I wish I could do something for you!”

“The Creator didn’t give me eyes so that I would embrace everyone, good or bad; so that every individual in this world is cared for. So, I would like to become friends and feel the warmth of their presence. Often I ask myself when they are going to notice that I am offering my love by hugging them. At least, I wish they saw my tears upon my separation from them…”

At first, I didn’t consider air as a living being! But now, I was learning that air was hugging me! And it was crying, too? Could the mechanical explanations be blinding me towards the reality behind the observations? If that were the case, the flow separation and vortex shedding were actually manifestations of melancholy. How is it possible that I am so distant to someone that is so close to me? My turbulence inside exhibited itself as a silence outside. At least, so, I thought. But I couldn’t be further from reality.

“I am used to this kind of silence. Despite their nonchalance towards me, I still care a lot about people. And using the subtle clues in their words and voices, I can penetrate into their psyche.”

Someone who knows me better than I? And I can’t even see that someone! When and how have I become its focus of attention?

“With their first breaths and cries in life, I start observing them from within.”

From within?

“With every breath, I become part of their souls, and with every utterance, I become part of their connections. Sometimes, I feel their inner pains through the trembling in their voices; the pains that they are ardently hiding even from themselves. As I leave them in that state, I break into a thousand pieces. But, the Creator made me invisible. So, none of what I learn about them is revealed to the eyes of strangers. Thus, I make a reticent confidant.”

I was totally conquered by these words. I found myself whispering “Not just reticent! You are a reticent and affectionate companion that anyone would like to have.”

“People live by breathing, and I breathe by loving; loving even if there is no reciprocity. As life goes on, I think about new people to be relieved of their pain, even if they won’t take me as one among them…”

“I love you air, I love you…”

Can an apple move the earth? Physics says it can. The power that gave an apple the ability to move the world, also gave us humans the capacity to make use of the natural laws and be a true vicegerent on the earth.

In a universal arrangement of objects, from the smallest to the largest, in terms of length, time, and mass, where is the human located? In between the diameter of an atomic nucleus (10-14 meters) and the distance of the farthest galaxy from the earth (1026 meters), the human being occupies a zone between one and three meters. The human lifetime can be measured to be around 109 seconds in temporal length, to the duration of a ray of light passing through a proton (10-24 seconds), to the age of the universe (1017 seconds). And the human mass is located around a 102 kg zone, on a scale from the mass of an electron (10-31 kg), to the mass of the Milky Way galaxy (1041 kg).

Based on this data, understanding the human that is trapped in this enormous universe is crucial. Humans are just a speck, jammed between mote and sphere, living in a frail state of weakness and poverty. “Do not strut about the earth in haughty self-conceit; for you can never split the earth (no matter how hard you stamp your foot), nor can you stretch to the mountains in height (no matter how strenuously you seek to impress)” (Qur’an 17:37).

Humans, who need a vast amount of grace and support, are in search of answers to improve themselves. “Who am I?” they often ask; “where am I?” As scientists and researchers discover the excellence of the universe’s artistry, we begin to comprehend just how blessed humans are. Within the laws of science lie the answers to our questions. Laws are relative principles that operate according to the constants wisely built into the universe. These laws are veils to the majesty of creation. Each law is created anew every moment, thus we perceive them as if they are eternal patterns. For example, the human body gravitates to the center of the earth with a force equivalent to their mass multiplied by the average gravitational velocity of the earth, which is 9.8 m/s2. The law of gravity is created every moment in such fine measures that it is possible for us to walk on the ground.

It helps to remember Newton’s three laws in physics. The first is the principle of inertia, which states that unless there is an external force, or if the sum of all forces cancel each other out in direction and size, then an object is either at rest or moves at a constant velocity. The second law is that force equals the mass of an object multiplied with its acceleration. And the third is the action-reaction principle, which states that when a force is applied to an object, the object exerts a force in opposite direction, equal in magnitude. This means that when an apple is thrown into the air, and the apple accelerates in opposition to gravity, the earth is distanced from the apple with the same amount of force. Similarly, when the apple falls down because of gravity, the apple is also pulling the earth with the same magnitude. If this was to repeat constantly, theoretically a movement like the one made by a yo-yo should have happened between the apple and the earth. Because of its huge mass, the earth’s acceleration is very small, thus this yo-yo movement would not be felt. An object as small as an apple actually moves an object the size of the planet. This means that the power that gave an apple the ability to move the world, also gave us humans the capacity to make use of the natural laws and be a true vicegerent on the earth.

Nothing in the universe has been created in vain – all phenomena occur because of a purpose they are assigned to fulfill. In a universe in which everything is bound by a complicated web of laws that are created without a moment’s lapse, humankind surely has a significant role to play in the unique position with which they are graced. This position undoubtedly requires a sense of humility in the face of all the grandeur around us, yet also being aware of our given capacities, which enable us to master over all existence.

In the mechanics of engineering, the force of inertia depends on the acceleration of a moving object along with its mass. Therefore, the force of inertia on an object is equal to the mass times acceleration. Accordingly, the faster an object gains speed, the greater will be the force of inertia. However, this brings along many problems in practice. In machines with pistons (compressors, pumps etc.) which are accelerating and slowing down speedily, a great force of inertia is applied to the machine’s elements. This gives way to a significant amount of resistance and abrasion problems. In addition there are other such troubles inside an engine’s cylinder during the four strokes (induction, compression, expansion, and exhaust). A greater force is required for brake mechanisms at the motion of elevators, banded conveyors, and automobiles. This is why brake linings wear out in a short time.

According to the principles of thermodynamics, where a piston-cylinder system is concerned and the compression or expansion of gases is slower, minimum energy is required during compression and maximum energy is obtained during expansion. On the other hand, if this process of compression and expansion is realized quickly, then the energy consumption is maximum during compression and minimum during expansion. Turning the tap too quickly to stop the flow of water causes a greater force of inertia inside, and if this continues to occur frequently, the faucet may need repair.

Things done too quickly present similar consequences. A person becomes rich as a result of working for long years has a better chance to appreciate his conditions in comparison to someone who becomes rich by winning a lottery. Decisions made in haste without consulting with others mostly yield negative results, which happens rarely in those made after consultation, since the risk of mistakes is reduced.

Living things and gradualness

For living things, adaptation to hot or cold environments is also a gradual process. If adaptation is not realized slowly, they cannot survive. For example, if a man starts by taking showers with hot water, then gradually with warmer water, and in the end with cold water, his body can develop endurance to cold water, even freezing water in winter. Some mothers wrap up their children too well even in good weather, and thereby do not let them adapt to changing weather conditions; such children catch cold easier than others.

Principle of gradualness has an obvious relation with being steadfast and patient, as in the cases of hatching chicks and silkworms in their cocoon. Human intervention to accelerate these processes will naturally have some negative effects. If the wing of a chick is forced to separate from the egg before the due time, it might hurt the animal seriously.

According to dieticians, stomach problems are more commonly found in those who eat quickly than who eat without haste. In addition, it is also known that meals cooked in low heat are more delicious and have higher nutritional value. It is essential for food quality to cool the foods gradually before they undergo freezing. Similarly, before cooking frozen food, it is advised to thaw out the food, gradually bringing it to values near room temperature.

A frog’s nervous system is sensitive to sudden changes, not gradual ones. For this reason, when it is thrown in hot water, it jumps back right away. But if the water is heated gradually, the frog will show no reaction, it will even enjoy it. Despite the increasing heat, the animal feels numb more and more, to such a degree that it fails to escape before it is too late. Even though there may be no obstacle to jumping out, the frog pays a heavy price for the heedless life it led. So, it is very significant to be able to observe the gradual changes and take measures accordingly.

Human life reflects this principle in many ways. From biological development to learning new subjects, different kinds of progress depend on a gradual process. Nevertheless, human beings are too impatient to follow gradual patterns. You may have heard from people who want to learn a new subject-such as a foreign language-express how they wish there were some pills or other quick ways to realize their aim all at once.

Indeed, mankind is ever hasty. Success and joy, however, rest with patience and being in the right tune with gradualness.

We certainly fail if we try to consider time as only a matter of determining the hour. It is, in fact, a dimension like depth, height and length. One reason of our difficulty in perceiving time may be caused by the fact that our optical perception is sensitive only to three dimensions, but no others. Many animals cannot comprehend the dimension of depth. Some animals see their environs in two dimensions as in pictures. We have difficulty perceiving other dimensions just as animals which see the world in two colors live without any awareness of other colors.

Humankind, with the most sophisticated aspects, has a very different and privileged position above all creation. In spite of this, we have limited sight, hearing, and other senses. Many a world that is beyond our senses remains imperceptible to us.

Another aspect of time that supports its dimensional feature is that it is in full conformity with and proportional to other dimensions. In terms of its extent, duration of events increases or decreases in parallel with spatial dimensions. Man lives for around sixty to seventy years, while microscopic animals live around one or two days. The life of the sun and the universe which constitute the macrocosmos is expressed in billions of years. On the other hand, the life of subatomic particles is expressed in billionths of a second. Thus, we assume them as being resonances. There is time reduction together with and compatible with space constriction on the sub-atomic scale, and this fact is yet another proof that time is also a dimension.

How shall we understand the other dimensions of space? What does the fourth dimension of space mean? Let alone describing, it is not easy to even imagine this.

If a is the length, a2 is the area and a3 is the volume of a thing, then what is a4? If we see space as a giant plain sheet of paper, that sheet of paper has no depth but only a surface. If we fold crumple it into the shape of a sphere, we obtain “Riemann space.” Just like we perceive the three-dimensional earth as a two-dimensional surface while we are on it, this 3-dimensional sphere made of 2-dimensional paper will be perceived as 2 dimensional by us. We can only talk about the third dimension after we generate a depth, that is, after we step outside the paper and move above and below it.

The fourth co-ordinate of space is a tunnel. Let us suppose that the universe is two-dimensional, that is, it is like a thin sheet of paper, and let us human beings be like pictures with no thickness over its surface just like the pictures on a newspaper. We are free to move in all directions on this sheet of paper. We can sense four directions. But we will never perceive the terms “up” and “down” (or “upper” and “lower”) since we will never leave the surface of this sheet of paper. Such terms will seem unacceptable to us even we are told of them. Accordingly, we will never hear of a third dimension and our vocabularies will never contain such terms as “up” and “down.”

If a three-dimensional object existed above our fictional paper realm and if this object even slit our paper realm and went away, we still would not see it in three dimensions but only the part of it intersecting our paper realm. If such a thing were a sphere, for instance, we would see its projection in a circular form. Its latitudinal sections would gradually expand starting from the poles, reach their largest on the equator line and its ring-like (circular) shape would gradually decrease and finally disappear at the other pole. That is, we would see it only as its cross section or shade. Such a three-dimensional object would seem two-dimensional to us since we would suddenly see its cross section. The sudden appearance, expansion, decrease and final vanishing of that spherical object in our two-dimensional realm would seem quite amazing to us since our shapes are fixed and immovable.

The three-dimensional shade of an extraterrestrial four-dimensional object overshadows our three-dimensional space. We see the linear tunnels in cross-section, not longitudinally, just as we see the sphere as circular. Though the sphere is a simple object, it amazes us.

Let us now imagine a more complex form. Let us, for instance, reflect the shadow of a vase onto a wall and obtain various shades by turning it repeatedly. A fixed and immovable portrait on the wall would regard the shadow and its variations reflected over the same plane with surprise and fear, since that portrait, or that person without depth, sees only what is reflected on the wall, but not us and the vase. The wall is the only realm for him and there is nothing for him beyond and behind the wall even if we say so.

We humans tend to assess events within the narrow limits of space and within certain dimensions, since we are bound within a single space–time cone. The conceptualization of space with its dimensions of height, length and depth is possible for us. However, the fourth dimension, time, is an abstract and metaphysical measure even though it is studied within physics. The tunnel thus seems to us like an incredible dimension.

Our perceptions with the five senses in the visible universe can be considered as the projections of non-physical and multi-dimensional realities (the eighteen thousand realms) to our domain. Clearly, in order to gain a better understanding of those realms, which we do not see but which we feel exist, with the help of the physics, we need to emancipate ourselves from the narrow patterns of time and space in this world of trial. We need to travel toward the horizon of spirit and develop an all-new scientific language which approaches physics and metaphysics together. Finally, we can say, in Bediüzzaman’s words, that the physical and observable universe which is the domain of research for modern physics is an ornamented curtain veiling the world of the unseen.

Osman Cakmak is a professor of chemistry at Gaziosmanpasa University, Tokat, Turkey.

One recent example of such phenomena is the Schrödinger equation that explains the behavior of matter at the atomic level. This relation just happens to work, and its derivation is intuitive rather than rational. It also has the simplest mathematical form among its possible competitors in terms of expressing nature.

We will now look at another example of such axiom-like relations that we usually ignore, although it is frequently encountered in our everyday life. Before revealing it as fully as we can, let us relate one situation where this effect is very apparent.

We usually move objects by pushing or pulling them. Suppose now we are on a motorboat and we have run out of gas in a place very close to the shore. We (the strong crew members) surely do not want to be carried away from the shore by the backwash from the waves. One of us has the brilliant idea to push on the sides of the boat until we reach harbor. What would you suggest? Some of us think that it is not a good idea because the boat is very heavy and our pushing will be negligible. It is true that the boat will not move. However, the failure has nothing to do with the weight of the boat. On the other hand, some other crew members suggest using oars, which will obviously work, but why? (Personally, with all my respect to other opinions, I would suggest using the phone to call the beach police to get some help; but this would distract us from our subject matter.)

Impulse, direction, and momentum

If you think about the “why” question above, you will guess that we are talking about impulse in the loose meaning of the word. In physics, impulse has a more precise definition. This definition arose from the need to describe an object’s ability to have an impact on other objects, but the idea is still vague: How do we quantify this ability in order to put some flesh on this notion? Let us try to figure out an answer to this question.

Now, let us consider a few possible ways of defining impulse that look reasonable. We may decide intuitively that an impact should be related to an object’s speed: the higher the speed the greater the impact. If you ever played marbles in your childhood, you will recall that the easiest way to dislodge the marbles in the targeted row is to cast your own marble as fast as you can. Impulse should also have a relation to mass. Certainly, the impact of as many as a thousand bullets aimed at a train will not move the train even a meter. These are some simple observations anyone can experience or have a feeling of from their daily life.

We also expect that this strange quantity should somehow be transferred by the interaction of two objects. One object colliding with another stationary object transfers something that causes the latter to travel in a direction. With this example, another important feature of our impulse idea emerges: direction. Those who like to play the game of American pool or billiards know this very well. (I am sure everyone does it for the noble reason to experiment the laws of physics.) It makes a significant difference in a collision of two masses if they hit each other at an angle.

Wait a minute! We have been talking about the effect of an object’s impact, but the object has something that it is carrying even before the impact, and this “something” is the reason why we have an impact in the first place. So, what is this “something”? Let us call it momentum so as not to violate the traditions of physics.

All this stuff so far is good, but we are not done yet: how should these ideas appear in our equations? Now, let us bring together all our findings. We know momentum manifests itself as the impact (P) of one object on another. From its effect (impulse), we understand that momentum is related to the mass (M) of the object and its velocity (V). We also know that momentum has a directionality, which is termed vectorial. Then, perhaps momentum is something like:

P = a x M + b x V

where a and b are constants. This seems acceptable since it satisfies our observation: the more the mass, the more the momentum. But for a stationary object (V=0), there is no point in talking about impulse; so the axM terms looks unnecessary. If there is no good reason for a physical quantity to appear in a physical equation, then the simplicity principle says it should be removed. Therefore, we look for a simpler alternative relation with only one term like below:

P = c x M2 x V5

where c is a constant. But this one is a highly non-linear relation with exponential terms, so it is really not looking good. Another problem with this equation is that it does not fit our daily experience very well. If we reconsider our train example, with a high velocity power term like this, even the very small bullets can have a considerable effect on a train, enough to move it in fact. As a simple example, let c be equal to 1, take 0.1 kg as the mass of a bullet and 105 kg (100 tons) as the mass of the train, and give 400 m/s velocity to the bullet. Assuming that the impulse of the bullet is transferred to the train (conservation of momentum), we roughly get:

Pbullet = c x m2 x Vb5 = 1011

Ptrain = c x M2 x Vt5 = 1010 Vt5

By equating both sides we roughly get, 1.6 m/s (5.7 km/h) for the train velocity.

A single bullet moving a big train at such speed? This is a very counter-intuitive result. However, we will not give up easily. How about if we try an expression which is more familiar?

P = d x MV2

where d is a constant. This relation also agrees with our intuition (i.e. it has mass and velocity terms proportional to P.) I can already hear some objections from those who are acquainted with physics saying “No! This is the energy formula of a body with mass M and velocity V.” Indeed, this equation is reserved for energy which is a non-vectorial quantity. As a matter of fact, none of the above is a correct description for momentum. The actual expression is, interestingly, the simplest of all possibilities:

P = MxV

So, why not the more complex ones but this, the simplest one? The rigorous answer is subtle and requires a thorough analysis of linearity and homogeneity of space, which could be the subject of another essay. But we repeat the remark that we made in the beginning: if there is a simpler and more beautiful way of describing a natural law, then that description often turns out to be the correct one in the end. In fact, for some giants of physics like Paul Dirac, the beauty of a theory is more important than its results and is a better indication of the theory’s correctness. There is more to it than that. There are whole theories like Dimensional Analysis which are implicitly based on the idea of writing down the equations in the simplest (and most beautiful) form.

So, the final point is that, like other fundamental relations in physics, the idea of impact or momentum is best described in the simplest and most intuitive way: P= MxV. And behold! This gives us exactly the relation that has passed all the scientific tests in the range of classical physics. This result implies that the beauties we see in nature can be explained in terms of the simplest possible physical relation. Pondering all these, one cannot help but ask how in the world a mindless, blind natural law could exhibit beauty based on simplicity.

In order to get a sharp image, ideally one point on the image (film) should receive light rays from only one point on the object. In practice, this ideal case can not be achieved in case of a large pinhole. If we have a large pinhole, as seen in Fig. 4, the light rays emerging from one point on the object reaches multiple points on the film. Also, multiple points on the object can arrive at a single point on the film. The result of both cases is a blurry image. For a small pinhole, however, there are light rays emerging from a point on the object in all directions, and only a very small amount of light is received on the film. To produce a decent image on the film, the exposure time needs to be very long, especially when a very small pinhole is used. Of course, we can make the pinhole a little larger to capture more light. But, wait! This would make the image blurry. Therefore, for pinhole photography, the size of the pinhole sets the quality of the image and the minimum exposure time. Also, we can take the picture of a still object, but a moving object cannot be captured easily by a pinhole camera due to the long exposure time. One important question is: Can we make reduce the size of the pinhole size to increase the quality of the image? Well, physics says: “No!” Fig. 5 shows a comparison of the images of a filament taken by a pinhole camera.⁶ As the size of the pinhole gets smaller and smaller, the effects of the diffraction phenomenon are more and more pronounced, and the image becomes blurry again. We also notice that the image is barely formed with a very small pinhole, indicating that very little light is received.

How can we gather more light and still make the image sharp? Can we achieve this with just the pinhole? Apparently not. That is why we mention lenses when talking about any imaging system. This is what a lens basically does. A lens gathers more light, and still preserves the one-to-one correspondence between the points on the object and those on the image. So, a lens is very useful for imaging. Most cameras have one or multiple lenses. Our eyes have lenses. We should remember, though, a pinhole camera takes a picture, but the compromise is the exposure time. Now, we see that a lens solves the exposure time problem, but is there a price to pay? To answer this question, let’s take a look at once again Fig. 2, where we see two pictures, one taken by a pinhole camera, and the other one by a lens camera. Look at the pictures carefully, and try to understand the difference before proceeding. As you probably observed, in the pinhole camera image everything in the picture is in sharp focus, from the close-by plants to the far distant beacon, and the clouds in the sky. However, in the lens camera image, only the closest daisy is in focus, and the other daisies, only a few meters away, are blurry. Indeed, we lose the depth of field in our images when using a lens camera. Depth of field can be defined as “The distance between the nearest and farthest points that appear in acceptably sharp focus in an image.” This is actually something we live with everyday. Try to focus your eyes on a mountain far away; the objects that are very close will not be in focus anymore. So, our eyes, consisting of lenses, also have limited depth of field. A nautilus eye, on the other hand, has an infinite depth of field, as it has a pinhole eye. Therefore, the price paid for gathering more light with a lens is that not everything will be in focus.

We can understand why lens cameras have a limited depth of field while a pinhole camera has nearly infinite depth of field if we consider the focusing mechanism of a lens. Given a pre-determined film position, a lens can only form sharp images of an object at a certain distance from the lens. Other points that are farther from or closer than same section of the object will be out of focus. However, if the size of the object is not large, we usually do not notice this effect. When we want to take pictures of close-by objects, then this effect is clearly seen, as Fig. 2 (b) shows.

Actually, we can correct this problem. The image of the farther points of the object forms at a farther point on the film. So, multiple light rays coming from one point will end up on the film. If we place an aperture next to the lens, then we can block some of these light rays. If we make the size of the aperture sufficiently small, we can get a sharp image of the farther point. Our original question about the lenses can be posed once again at this point: By using the aperture we make the image sharper, but what do we lose? Of course, since we block some of the light rays, we lose the light-gathering ability of the lens. Now, if we make the aperture size smaller and smaller, we finally reach the pinhole, and an almost infinite depth of field!

Our eyes also use similar mechanism of placing an aperture. The amount of light allowed to enter each eye is controlled by the iris, a circular diaphragm that opens wide at low light levels and closes to protect the pupil (the aperture) and retina (light detector of the eye) at very high levels of illumination. As illumination changes, the diameter of the pupil (positioned in front of the crystalline lens) reflexively varies between a size of about 2 to 8 millimeters. When illumination is very bright, the pupil narrows and light rays from the side are excluded from the optical pathway.⁷ The result is a sharper image on the retina. A very narrow pupil (approximately 2 millimeters) produces diffraction artifacts that spread the image of a point source on the retina, similar to the image of the filament captured by a very tiny pinhole (Fig. 5)

In conclusion, a pinhole camera is a very instructive tool for learning about imaging concepts. A pinhole camera has an infinite depth of field and the ability to produce sharp images regardless of the distance of the objects. This comes with a price, though: the small size of the pinhole limits the amount of light received by the film, so long exposure times are needed. A lens helps to gather more light, but compromises the depth of field. These concepts are used in imaging technologies, and can be found in the eyes of living organisms.

Notes

1. E. Hecht, Optics, 2nd edition, pp. 199. Addison-Wesley Publishing Co.
2. http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T045986A.gif.
3. http://www.kosara.net/gallery/.
4. http://www.eyedesignbook.com/.
5. http://www.spylife.com/pinholecam.html.
6. http://www.umiacs.umd.edu/~ramani/cmsc426/Lecture3.pdf
7. http://www.olympusmicro.com/primer/lightandcolor/humanvisionintro.html.

Be they physical or chemical, many attributes of beings are dependent on mathematical laws and their appearances are also shaped along mathematical principles. When we observe creation from this standpoint, we can perceive the perfection as well as the spectacular beauty that is inherent in every being. As reflections of the Attributes of the Names of God Almighty, Jamil (The Owner of Beauty), Bari (The One Who Creates from nothing), Sani (The Maker of All) and Musawwir (The Designer), this beauty found in the external appearance of beings is dependent on more than one factor coinciding. The most important factor here is “symmetry,” which is described as “an exact correspondence and beautiful balance among the parts of an object.” Beings are created with various symmetrical attributes and with great artistic beauty.

The most common symmetry type is the bilateral symmetry; this creates a mirror effect which is an exact correspondence between the right and left sides. An object forms an exact symmetry with its reflection in the mirror. A perfect symmetry that is very similar to the mirror effect can be found in the human body. The left and right sides of our body are symmetrically corresponding. Imagine a dividing line that passes from the middle of the forehead, through nose, chin and down the chest, we can see a perfect symmetry on both sides of the body. Our arms, legs, eyes, ears, nose and lips are designed with a bilateral symmetry. The same symmetrical structures can also be seen in most other creatures. All mammals, reptiles and birds are symmetrically created.

Another type of symmetry is rotational (radial) symmetry. Imagine a metal object that is in the shape of an equilateral triangular placed on the sand. If we will rotate this object 120o around an axis that passes through its center, the new position of the object will fit exactly into its original mark left on the sand. The reason for this is that the radial symmetry for equilateral triangles is 120 degrees. In the same way, a square has a radial symmetry of 90^o and a regular polygon with n number of sides has a radial symmetry of 360/n degrees.

The beautiful symmetry of snow flakes, with their regular hexagonal shape are a beautiful natural phenomenon. In addition to these there are shapes in nature that have a three-dimensional radial symmetry. The most significant of these shapes are regular polyhedrons. An example of such polyhedrons is the salt crystalline elements that have cubical structures. Until recently, the fact that there is a creature in nature that has a regular polyhedral shape, consisting of twenty sides, was unknown. However, when a type of adenovirus that causes infections and hepatitis in dogs was discovered, it was found that there is a creature with twenty regular sides in nature.

One of the most beautiful samples of radial symmetry in nature is the daisy. Symmetrical structures do not only exist in the normal world and in the micro worlds, but also can be found in the macro world, like all the huge celestial objects, the Sun, the Moon, galaxies, star clusters in the sky . . . . All planets move around the Sun in a symmetrical manner, whereas galaxies have a spiral symmetry. It is interesting that the symmetrical structure of living beings is overwhelmingly apparent externally, rather than internally. For example, the internal organs in the human body, like the lungs, liver, stomach and intestines are not symmetrical and we have only one heart in one side of our chest cavity. Moreover, the lobes of the brain are not symmetrical either. However, all the metabolic processes in human body function properly. Does this mean that the mathematical beauty found in our external appearance is merely for aesthetical reasons? God does not create things for only one reason or purpose, on the contrary, He creates them to serve many motives and in relation with many functions. For example, if we did not have two eyes and if they were not symmetrically placed on our faces, we would not be able to see objects three-dimensionally. In the same way, if our ears were not symmetrically placed on our heads, then we would have great difficulty in determining the direction and source of sounds. If we did not have symmetrical feet and legs, we would not be able to walk well, and if our arms were not symmetrical, we would not be able to balance our body’s center of gravity while walking. If birds did not have symmetrical wings, they would not be able to fly, and if the fins of fishes were not symmetrical, they would not be able to swim smoothly.

Symmetry is also closely related to physical and mental robustness. According to one study, women who suffer from an infectious disease during pregnancy are more likely to have babies with asymmetrical features. The same study claims that asymmetrical babies are more susceptible to heart disease than symmetrical babies.

Another study shows that people with asymmetrical teeth are more likely to have more harmful microorganisms in their mouth than those who have symmetrical teeth. It is interesting that there tends to be a greater difference between the fingerprints on the left and right hands of schizophrenic people than on those of normal people.

Symmetry is a phenomenon that is used by animals and insects. For example, an experiment showed that bees prefer flowers that are symmetrical. Actually, flowers with perfectly symmetrical shapes produce more nectar than those that are asymmetrical. In one investigation, a symmetrical flower was made asymmetrical with a pair of scissors. The flower had been attractive to bees before its shape was changed; after made asymmetrical, the flower became unattractive to bees, even though it had just the same amount of nectar as before.

All these facts reveal that there is much wisdom and beauty hidden within the symmetry that the Almighty Designer uses to shape all beings. We take symmetry for granted. To have two eyes placed equidistance and two ears on each side of the head is the norm. Anything else strikes us as strange. But if we just take a few moments to think about why our eyes are where they are, and why our ears are placed on the sides of our heads, the answer is obvious. God’s mercy is infinite; in even the simplest example of symmetry there is a reason. We should not take this world for granted, but rather use every opportunity to dwell upon and be thankful for the wonderful world that has been created for us. 

References

• Stewart, I. & M. Golubitsky, Fearful Symmetry, Blackwell, 1992.
• Rosen, J., Symmetry Discovered, Cambridge University Press, 1975.
• Tarasov, L., This Amazingly Symmetrical World, Mir Publishers, Moscow: 1986.

Every soul shall have a taste of death (Quran 3:185). Like everything else, stars live and die. Would it make any difference if you knew that the iron in your blood and the calcium in your bones had been assembled inside stars? Atoms heavier than iron are formed by rapid nuclear reactions that can only occur when a massive star explodes. Gold, which is not crucial for our lives, and iodine, which is important for our health, are available, thanks to the violent deaths of massive stars.

The death of a star leads to one of three final states. Most stars, including our Sun, will become white dwarfs, stars about the size of the Earth, with no usable fuels. But the most massive stars explode and leave extraordinary objects behind; either a neutron star or a black hole.

The Sun resists its own gravity by generating energy through nuclear fusion. Under extreme conditions, four hydrogen atoms are combined to form a helium atom, and the mass difference between these atoms are converted to energy which can be calculated by Einsteins famous equation, E=mc², where m is the amount of mass converted to energy and c is the speed of light. In 4.5 billion years, the Sun will exhaust the fuel, hydrogen and helium stored in its core. This will start the chain of events that will result in its death. Since it will not be able to generate any energy to balance the huge weight of its outer layers, it will collapse. This will result in an increase in the temperature around its core. This temperature increase in the shell around the core will start new reactions which will produce excess amounts of energy. This extra energy will cause the Sun to expand and become a red giant. Its size will increase to such an extent that it will swallow Mercury and Venus, and maybe even our planet, Earth. As a giant star, it will have a strong solar wind that carries gas into space. Eventually, it will lose its outer layers, and produce a beautiful planetary nebula.¹ Soon the remains of the Sun will collapse and form a very compact object; a white dwarf. Imagine squeezing the Sun into a planet the size of the Earth. Gravity on a white dwarf is 10 million times greater than it is on Earth. Thus, a person weighing 150 pounds will weigh 1.5 billion pounds on a white dwarf. The white dwarf will burn 100 times fainter than our Sun; if the Earth survives the red giant phase, it will fall into a deadly deep freeze, and would not be a pleasant place to live.²

Medium mass stars, like the Sun, die relatively quietly as they exhaust their fuel and form white dwarfs. In contrast, massive stars live spectacular lives and destroy themselves in violent explosions. Massive stars have too great a mass to die as white dwarfs. They consume hydrogen and become red giants, but unlike the medium mass stars, their core temperature is high enough, about 1 billion degrees, to ignite carbon fusion. After they fuse carbon, they burn oxygen, neon, and magnesium to make silicon and sulfur, and then the silicon fuses to make iron. Iron is the most tightly bound of all atomic nuclei. Nuclear fusion is able to produce energy by combining less tightly bound nuclei into a more tightly bound nucleus, but iron is the limit. Once the core of the star has been converted to iron, there are no nuclear reactions that can burn iron and release the energy. Thus, the iron core is a dead end. The iron core sucks energy from the rest of the star. Since the star cannot produce any energy, it cannot resist its own gravity. In a fraction of a second, the star collapses in on itself. The collapsing core of the massive star quickly becomes a neutron star or a black hole. This collapse happens so rapidly that our most powerful computers are unable to predict the details. The envelope of the star collapses and bounces back off the dense core, which triggers a violent supernova explosion that expels the outer layers of the star to form an expanding supernova remnant. This explosion enriches the neighboring media with iron and other metals. If you throw a water balloon at your friend, your friend will get wet. Massive stars are not water balloons, but they are iron, silver, and metal balloons. When they explode, they seed the interstellar medium³ with metals. If there had not been a massive star death near our solar system when the Sun and the Earth were forming, our solar system would be iron-poor, and we would not be living today. Massive stars die so that we might live. The Quranic verse We have sent down iron, with its mighty strength and diverse uses for mankind (57:25) sheds light on this fact 14 centuries before it was discovered. Only in the past century, with the utilization of modern telescopes, have we had evidence of this. Nursi explained the above verse as iron is sent down together with the globe of the Earth from the Supreme Treasury, as a tremendous bounty. That is to say, the thing most necessary for the house of the Earth is iron, for when the All-Glorious Creator separated the Earth from the Sun and sent it down for mankind, He sent down iron together with it, and met most of mankinds needs with it. The All-Wise Quran decrees in a miraculous fashion: Use this iron in your works and try to excavate it and take advantage of it.⁴

A neutron star, on average, is 1.4 times more massive than the Sun, and is compressed to a radius of about 6 miles. Its density is so high that matter is stable only as a fluid of neutrons. An atom is mostly empty space. The nucleus of an atom is very small compared to the size of the atom. If we represent the nucleus of an atom with a blueberry, then the distance between the nucleus and the electrons would be as great as the height of the Empire State building. If you could eliminate the empty space in atoms, you would be able to squeeze stars larger than the Sun into a radius of about 6 miles (the radius of a neutron star). A neutron star spins several times a second, and has a magnetic field a trillion times stronger than that of the Earth. Observational evidence for neutron stars was first found in 1967 when astronomers found a neutron star (pulsar) rotating around itself in 1.3 seconds and sending radio pulses to Earth. If you have a large enough antenna, you can pick up periodic radio signals from pulsars. On Earth, a teaspoon of the material from a neutron star would weigh 100 million tons.

Another scenario for the end product of the death of a massive star is a black hole. When the core of a star contains more than 3 times the mass of the Sun no known force can stop it when it collapses. The object will not stop collapsing when it reaches the size of a white dwarf or a neutron star, because the electrons or neutrons cannot support the weight of the star. The object will collapse to zero radius (or almost zero radius) and form a black hole. Objects need high speeds to be able to leave another object, to be able to resist falling back due to the gravitational pull of the other object. For example, a space shuttle must reach a speed of 11.2 km/s to to be able to leave the gravitational pull of the Earth in order to go into space. Gravity is so strong near black holes that the escape speed from a black hole is greater than the speed of light. Thus, even light cannot escape; this is the reason why these phenomena are called black holes.

As an object collapses, its gravity increases. If it collapses to zero radius, its density and gravity become infinite. Such a point is called a singularity. Clocks slow down near a singularity. If we were able to watch a person falling into a black hole, we would see them moving more slowly as they came closer to the black hole. In fact, the person would never disappear from sight. From where we were standing, this person would fall more and more slowly, until finally they would hardly seem to move at all. Generations later, our grandchildren would be able to look at this friend approaching the black hole, but never crossing the event horizon (the boundary of the black hole). Black holes are not giant vacuum cleaners that will pull in everything in the universe. A black hole has a huge gravity pull, but its force is quite small if you are not near it. If the sun were replaced by a black hole of a similar mass, the orbits of the planets in our solar system would not change at all. The gravity of a black hole becomes extreme only when approached. There are many black holes in the universe, but they do not pose any threat for us as long as we stay away from them. Next time you advise your children to stay away from strangers, remember to tell them to stay away from black holes, as well.

Footnotes

1. A planetary nebula is an expanding shell of gas ejected from a star, and it has nothing to do with planets.
2. Seeds, M.A., Horizons: Exploring the Universe, 2002, Brooks/Cole
3. The gas and dust between stars.
4. Nursi, S., Flashes, Sozler Yayinevi, 28th Flash