Carbonstuff

The above images depict the archaeological site of Göbekli Tepe.

We humans tend to be very obstinate about our interpretation of early human history; early humans were peripatetic hunter-gathers, who ventured out of Africa, discovered farming, formed cities and created great civilizations. Being the mumpsimuses that we are, any evidence that refuses to corroborate with this model will be viewed with immense skepticism. But, in fact, we have fresh evidence that might just force us to change out interpretation. Göbekli Tepe is an archaeological site that could very well turn over our fundamental notion of early human history on its head. So, let’s pick apart what we have here.

But, first, where and what is this Göbekli Tepe? Located in the Anatolia Region of Turkey, it is an ancient settlement dated to the time in between the Paleolithic and Neolithic eras. It consists of a huge stone complex in a peculiar quiddity; pillars arranged in concentric circles around central pillars, some of which are 15m in height! The pillars are ornate with carvings of animals.

Apart from the overawing immensity of the excavation, there lies a more subtle yet Earth-shattering fact; the site is 11,000 years old, a full 6,000 years before the famed Stonehenge. Not only did the people of that time not have metal tools to work with, they also did not know farming. It was therefore, nomads who achieved this amazing feat of engineering.

When one’s food is obtained by running and hunting fleet deer and other nimble animals, it is pretty reasonable to assume that one would be too exasperated to do anything but eat and sleep. Ostensibly it seems that, they couldn’t have developed the technology needed to make such humongous monuments. But then here we are, presented with what apparently ought to suggest that our nomad ancestors did have such abilities. How were they capable of creating such grandiose structures of immense proportions?

Perhaps more importantly, the question we should ask is why? Why go to such painstaking lengths to create these monuments?

Well, it all boils down to that large scale human organizer: religion. It is not surprising that humans are willing to do anything in the name of faith and organized religion; even build huge stone complexes. But if religion is indeed the motive behind these structures, it introduces another bewildering problem: religion was not supposed to have sprung up until after we started farming and city building.

We can all agree that the great watershed moment for mankind was when we left hunter-gathering to take up a life of farming; a momentous occasion that propelled us into the space age. Anthropologists and archeologists prodigiously enunciate that farming created the environment to constitute organized settlements, which subsequently led to religion. So first came farming and settlements, and then came religion.

But, befuddling us now is the fact that Göbekli Tepe seems to be completely antithetical to that view. The monument at Göbekli clearly indicates a divine purpose; it shows the connection the people of the ancient site had with their religion. It would certainly be a logical step to conclude that, the people of Göbekli followed a religion, and indeed, before they were farming. Yes, it is a bewildering prospect, but the evidence speaks volumes, and we cannot ignore that.

Now, here is where we get to the addling crux of it all. Some archeologists hold the view that we’ve got the picture of human development completely wrong, and they are using Göbekli to leverage their point.

Religion, they hypothesize, was the makebate that caused people to start farming; and subsequently build settlements and civilization. It was therefore, the development of religion that was the watershed moment in human history. Religion created a new mentality within the people; it was a pivotal shift in the hunter-gathers’ perception. It promulgated that man was somewhat different from the animal kingdom; that he was higher, stronger than them. The people therefore felt an obligation to honour this boon that religion had bestowed them, and they only way they could think of to this was to build huge stone monuments honouring their gods.

During the site’s construction and usage, a multitude of nomads from all over the region would congregate together. This would inevitably result in a conflict between these people; there would be the insuperable problem of cohabitation. And here too religion steps in. The new religion would admonish peace and convivial behavior between different tribes. So, they could then work cohesively to advance their divine obligation. Thus, many people would eventually settle together to support the temple. Subsequently, this would create the pressing imperative of feeding all these increased mouths, and maybe farming could have been used to combat this problem.

To summaries, Göbekli Tepe shows that the erection of monumental complexes was within the capacities of hunter-gatherers and not only of sedentary farming communities as had been previously assumed. More importantly, it points to the fact that religion and the mobilization of labor behind the building of religious centers like Göbekli Tepe were the chief factors driving the development of civilization and the transition from the Paleolithic to the Neolithic ages. As chief excavator Klaus Schmidt puts it, "First came the temple, then the city". Göbekli Tepe, therefore, is the most important archaeological site in the world.

With exams just around the corner, things have gotten a bit hectic here. As a result, I haven't posted any article recently; I also won't be able to post any article this month.

So, I'm taking a break from posting, and I'll continue in late December when things (hopefully!) will get back to normal.

A weird silvery-transparent liquid; tasteless, formless, expressionless, and yet it lights up the hearts of millions. It can be benevolent and invigorating at its calmest, and veritably malevolent at its most acrimonious. Indeed it is most capable of scalding, freezing and swift brutality. And yet, its caressing feel will mollify even the most of parched of lips. Constituting 70% of our beloved Earth and 60% of us, this liquid goes by the name of dihydrogen oxide; water to you and me.

Water is unlike any other chemical in our varied universe; indeed, it flummoxes even the best of us. Water seems to be asininely unaware of the laws of nature.

If you were to look at water’s cousins (namely hydrogen compounds with elements under the same group as oxygen in the periodic table; they generally have similar properties), e.g., hydrogen selenium and hydrogen sulphide and predict its properties—you would be forgiven to cerebrate that water would be a liquid at sub-zero temperatures, boil at -93⁰C and exist as a gas at room temperature. It is truly a unique character indeed, because in reality, it behaves nothing like this.

Cool water down and it starts to innocuously contract (decrease in volume and increase in density); just like a normal liquid should. But, after 4⁰C it springs back up and expands almost feverishly, becoming less dense. This beguiling fact means that solid form of water, ice, paradoxically floats on water. This obviously has immense consequences; not least the fact that it stops water bodies from freezing completely, and destroying all sea life.

When a water body is cooled down, its top layer freezes first. Now since ice is lighter that water, the top layer of ice floats on the surface. This effectively insulates the water below from any temperate change, thus sparing the sea creatures in the water from a frosty death.

Perhaps more amazing than this is that all these watery absurdities can be elegantly explained with a single stroke of chemical ingenuity: the hydrogen bond. Let’s see how.

Take a look at the structure of water.

Two hydrogen atoms share electrons with an oxygen atom in the proverbial covalent bond. But, this sharing is not all fair play. Oxygen is promiscuously greedy; edging the electrons more towards it. This makes oxygen negatively charged and hydrogen positively charged. A charge separation is created and hence; water is a polar molecule.

The two positively charged hydrogen atoms provide an irresistible treat to any negatively charged atom, including an oxygen atom from another water molecule—which indeed is negative. Thus, an oxygen atom of one water molecule sort of binds with hydrogen of another, producing that most crucial hydrogen bond.

This changes everything. Hydrogen bonds attract water molecules towards each other; it bands them together. Consequently, this allows water to exist as a liquid when most of its brethren would be floating away as gases.

Water molecules engage in a kind of dance; bonding with other molecules and letting go, then only to bond with other water molecules. This dynamic swapping of partners is happening all the time; even in the most insipid of water bodies. Just take a look at a simple glass of water; can you see the water molecules dancing?

The strength of hydrogen bond is crucially important. For it was off by just a few percent either way; water would exist as a gas or a solid. Hydrogen bonding—it appears—should be tight, but not too tight.

Another untenable property of this untenable substance is that, due to its polar nature, it can dissolve almost anything. In fact, water is the de facto solvent; the universal solvent.

To remark that this property is vital for life is a gross understatement. Virtually all biological activities happen in solution, in water. The movement of ions, the metabolic cycles, the folding of proteins, the catalytic activities of enzymes and the list goes on and on. It is hence that water is pertinent to all living systems on Earth. Indeed, most inorganic reactions conducted in a lab are in solution as well.

As if these properties were not prodigious enough, there is more. Water has a high specific heat capacity, which means that it can hold a lot of heat. On the small scale, this creates that soothing sea breeze; on the large scale, it barricades much of the Northern Hemisphere from retreating into another ice age.

Frozen water—or ice as it is more commonly known—present in large amounts at the poles may seem discreetly removed from us, but mind you, it's anything but. It is a big player in our global climate. Ice has the property of reflecting sunlight and heat and regulating Earth’s temperature. If the ice were to melt (by global warming), it would create many ill effects indeed; effects we are alarmingly starting to experience.

It would create untold flooding, devastation and in the process raise global temperatures. And maybe therein lies the more cloistered, insidious side of water; a side we are increasingly going to encounter.

The above image depicts the chemical structure of the molecule ATP.

Let's talk about the cell again! More specifically, the energy transportation of the cell and a little molecule called ATP (Adenosine Triphosphate). As we discussed earlier, chemical reactions are very important to a cell; indeed, it is one of its basic functions. A menagerie of reactions go on in all of our cells every second; a bond is made, another one broken, some atoms exchange partners, and many other wondrous events that form the quiddity of a chemical reaction. And if you can recall from last time, we found that energy is vital for a reaction to occur. Besides, a multitude of other activities require energy as well: muscle contraction, movement of molecules, reproduction, etc. So, you can imagine that the cell is a prodigious power hungry machine. Depending on the organism, there are an assorted number of ways to obtain energy; some do it with the help of sunlight, some harness the energy of chemicals trapped in our Earth, and some still feed on other organism. But regardless of the source, the energy is still used in the same way.

All the more complex cell obey a principle of compartmentalization, i.e., where tasks of the cell are carried out in specific discrete compartments—known as organelles. Things are not spread out all over the place; rather there are different specialized areas of a cell that undertake different specialized tasks. For e.g., production of proteins are done in ribosomes (an organelle), destroying de trop materials are done in lysosomes (another organelle), etc. This allows for these processes to be localized, and it generally makes the cell a lot more efficient; if the chemicals for the many processes needed for a cell are spread all around the cell, they would indubitably clash and hence, not much would be able to happen.

Before going any further, I would like to expatiate on this discussion a bit more with an analogy. Let’s make a comparative between the cell and city again (click here to read more on that). In a city, there is compartmentalization, and specific activities are done in specific areas; manufacturing has its own area, governance has its own building, companies have their own offices, there are separate areas for living, etc. The area that would be interesting for us is the power generation area; it is the area where the electricity, an imperative for the city, is produced. Now, this power—although produced only in the power station—is needed in all areas of the city. How do we provide the other areas with this power? In a city, we would use a power grid; it can transport electricity to all parts of the city.

In cells too, we have specific area or organelles for energy production, e.g., the chloroplasts in leaves, or a mitochondrion. But as noted above, this creates another exigency; the energy produced in these organelles need to be transported to other areas of the cell for proper functioning. We need a method to provide all the areas of the cell with energy. This is where molecule ATP comes in.

Adenosine Triphosphate, or ATP, is the energy currency of the cell. It acts like a battery, containing stored energy that can be used later. It is like the power grid of the city; energy is produced in one part of the cell is stored and transported to all other parts of the cell through ATP. Due to the chemical nature of this molecule, it has immense energy storing capacity. The energy storing capacity of ATP, rest on a basic fact of chemical bonding. To form a chemical bond, we must give energy; to break one, we will get energy. The stronger the bond, the more goes into making it. So, one can store energy in a chemical bond, and break it to obtain that same energy as needed.

ATP consists of a base molecule adenine, and is connected to three phosphate groups. The bond between adenine and phosphate is immensely strong; on breaking it, a prodigious amount of energy is released. This is essentially what happens in a cell. A mitochondrion or a chloroplast produces energy, and packs it into an ATP molecule; this can then be broken by hydrolysis (reaction with water), rereleasing the energy created earlier. ATP is used all throughout the cell; every action, every reaction of the cell requires ATP. It can be seen moving all around the cell.

The above images depict the scope of study in science.

Science today, is the crème de la crème of human knowledge and the center of our tech-savy culture. It is the quintessential 'double edged sword'; it can be used for achieving the sheer amazing or the macabre destruction of everything. With science in our hands, mankind has ambled to the greatest of heights and also the lowest of low.

But at heart, it is all pure. There is nothing else that can be more euphoric, exalting, exasperating, head breaking, heartwarming and overawing all at the same time. The goal of science is quite audacious—if not a little chutzpah. It's nothing less than to understand it all: atoms, cells, life, death, the universe and beyond.

It is by nature, a very human endeavor; an extension of our curiosity. Great minds have dedicated all to this most prodigious of human undertaking. The far reaches of the universe and the befuddling land of the tiny, all are in grasp when we delve into science. So, what exactly is this science?

To Know

The etymology of the word science stems from the Latin word scientia, meaning knowledge. And during the early ages, it was exactly that; any form of knowledge was called science. Be it about the natural world or about abstract mathematics, all of this was called to science.

Then during 17th and 18th century, the Age of Enlightenment and the Renaissance, people started to rediscovery ancient Greek texts, and Newton came up with his classic laws. It was a time of revelation; the pillars of modern science such as Newtonian physics, thermodynamics were all established during this time.

It was also during this time that the meaning of science got closer to what used to be called 'natural philosophy', namely the study of natural phenomenon. This is modern science; it includes physics, chemistry and biology as broad categories.

Modern science is built on the strict ideals of empiricism, falsification and the scientific method.

Science and Its Products

We have been talking so much about science; yet, we have not formally defined it. 'Science is the means of organizing and pursing knowledge, through testable predictions.' 

Notice that I said that it is the means of pursing the knowledge; the knowledge itself is not science, rather they are products of it. The manner if obtaining knowledge is judged as scientific or not; not the knowledge itself.

Science is more than just facts. It is an ideology; a way of thinking. In science, nature is considered not to be capricious. Nature is governed by laws, and those laws are universal and completely understandable by probing it, i.e., doing experiments. Thus, experiments form the very veritable substratum of science. All knowledge is a posteriori, i.e., only experiments can confirm a hypothesis. This ideology is called empiricism. 

Scientific Method

The means of carrying out an experiment—so central to science—is by using the scientific method. It is the pièce de résistance of any endeavor in science. It consists of a series of steps as described below:

Observation: This requires observing the natural phenomenon and recording data.

Pose a question: If such data cannot be expounded by current theory, a question should be posed as to why this is so? Do we need a new theory?

Hypothesis: An appropriate answer should be formulated for the above question. It would be sort of like a hunch or a guess that you have.

Make some predictions: This is the important bit. After formulating the above hypothesis, some testable predictions should be made. These are extensions of the hypothesis; the extrapolation of your hypothesis to other situations. Science is based on empiricism and falsification, where a hypothesis should be able to make predication that can be easily tested to ascertain the hypothesis.

Experimentation: These predictions are now tested. 

Results: The results of the experiment are taken and checked to see if the predictions match the results. If they don't, we need to start all over again and come up with another hypothesis.

Theory: If a hypothesis has passed all this, it is accepted into the general scientific community, and is called a theory. A theory accurately explains the phenomenon in question, and it is generally accepted as 'true'.

The word 'theory' in science does not mean the same as it does in common parlance. In common language, it generally means something that is not proven. But as far as science is concerned, a theory is an accepted explanation for a phenomenon; it is proven to be right to the best of our knowledge.

The hallmark of a good hypothesis is its ability to produce large amounts of testable predictions (which should come true of course!). The process of obtaining scientific knowledge from testable experiments is called the scientific inquiry. It is very important for a hypothesis to produce some viable statements and predictions, which can then be tested.

Keep in mind that even if a hypothesis becomes a theory, it can still be rejected later if new experiments and evidence refute it. And this brings us to the next section.

Best Fit Theory

Due to the nature of science, no theory can be perfect. There is no permanent or absolute truth. Falsification demands that even if one trifle shred of evidence is found that contradicts a theory, it should be rejected. In that sense, no theory is the absolute and dogmatic truth, and that is why scientists call a good theory a 'best fit' one, i.e., the one that best explains the body of evidence discovered currently.

It may happen that some new technologies and new evidence may contradict a well-established theory in the future, and in that case it will have to be removed from the textbooks (or at least altered).

Take the example of Newtonian Mechanics. For over two centuries it was unchallenged and accepted as true. But, in the 20th century, new evidence, taken with more precise instruments, found it deviating from the experimental data. So it had to be rejected, since new evidence was found that contradicted Newton's theory, and modern mechanics—most notably by Einstein, Bohr, Planck, and others—was developed.

But again, this does not show that all scientifically accepted theories are intrinsically unstable or untrue. If a theory is accepted into science, it is scientifically true and, it can be used to explain a multitude of phenomena. But, those same rules of science that give credibility for a hypothesis to become theory, also give the freedom to undermine it if new research and evidence does not corroborate with it.

Some people cannot get their heads around this concept. So, let us make an analogy. Science is almost like a democracy, where the people of the scientific community are citizens of this democracy. These citizens vote for the leader who will best adapt to the needs and situation of the country at that time; in the same way, scientists favour or ‘vote’ a theory that best suites the evidence. So for this particular time period, that person who was elected is called the ruler. Akin to this is when we call our theory as the ‘truth’.

Now if the situation in the democracy were to change to a state in which the incumbent ruler would be unable to rule decisively, he would then be replaced. Taking the analogy forward, a theory would be ‘replaced’ if it is found that it cannot cope with some new evidence found.

In short, one can say that a theory is a ‘scientific’ truth, but not the ‘absolute’ truth.

We can conclude therefore, that science is an ongoing process; it is never 'finished'. New questions are always being formulated, and new answers are being thought of for whilom questions.

Science in Our Genes

Science is the most human of activities; our DNA is endowed with it. All of us have a restive passion for discovery. Nature has always intrigued us; it truly piques our curiosity, and stokes our fervor for discovery.

Also, science is a very democratic endeavor; no theory is allowed to exist if it doesn’t deserve to. It is egalitarian, in the sense that any theory can replace another if it has sufficient evidence (remember our earlier example?). Through the principle of falsification described above, no theory can claim to be the permanent truth. This stops science from being a dogmatic creed, and prevents it from receding into the abyss of pseudo-science. This maintains the consistency of our knowledge.

Atoms have a mind of their own, drifting around, combining with other atoms along the way, and finally wavering away to find another partner to pair up with. It's almost like a dance party gone wild. The befuddling thing is that out of this mess, these bewildering atoms come together in many a relationships to form all complex systems known to exist: molecules, fungi, plants, you.

We all learnt about atoms in school. Their inner arrangements are akin our solar system; planets revolving around the sun, where the electrons are like the planets and the nucleus like the sun. To tell you the truth, that picture is totally wrong !! Let me explain.

All That Space

Well, for starts, it’s not the neat picture that textbooks show it to be. For example, if the neutrons and protons are say 10 cm across and the electrons .1 mm across (the electrons are really that small compared to the protons and neutrons) the entire atom would be 10 km across! 

Yes 10 kilometers. Let us put that in perspective, if the whole nucleus were a fly in the center of a football stadium, then the first electron would probably be way out of the stadium.

What we can see from this is that the atom has exceeding amounts of empty space. Thing about it. You are made of trillions of atoms; now imagine all that empty space in one of those atoms. Now, imagine the empty space in ALL those atoms put together!

We can therefore cerebrate the benign fact that we are mostly empty space! What professes to be solid is, in actuality, prodigiously empty space.

Quantum of Atom

Niels Bohr, the great Danish physicists, was the first to give a decent theory explaining the atom. Problem is that it required queer and sometimes even inscrutable assumptions. 

One, is that electrons revolve around the nucleus; and they do so only in fixed energy states around the nucleus. This means you can’t find electrons anywhere you like, only is specific energy levels or orbits around the atom.

Two—and this is the weird part—the electrons can jump from one energy level to another, given enough energy. This was termed ‘quantum jumps’. As electrons jump, this subsequently begets a photon of lights. 

This theory was the beginning of the quantum theory of the atom.

                The Fuzziness of The Atom

The difference between waves and particles is that particles are discrete objects with momentum and speed and mass, wave are not. Rather, waves are a fluctuation of energy that travels across space and time, with no momentum and speed.

Louis de Broglie, came up with the astonishing idea that all stuff, particles or waves, exhibit wave nature.

But, to reconcile de Broglie’s findings, physicists had to accept the idea that all particles, including electrons ( as well as you and I ), are waves as well as particles.

This means that we had to throw out all our previous mechanics and come up with a new one, Quantum Mechanics. Sounds scary doesn't it ? Well, it is. But, let's bravely go on.

One of the most fundamental and profound principles of Quantum Mechanics comes from this wave particle duality. It says that since everything is a wave as well as particle, we can never know a particle’s momentum and position at the same time. This is the famous Heisenberg's Uncertainty Principle. It basically says that an electron can be in more that one place at the same time. That’s right! There is no fixed position that it has. We can only specify the probability of an electron to be in such-and-such place.

This means that we have to completely discard Bohr’s neat energy level theory. Since, we cannot say where an electron is, we can’t assign energy levels (a position) to it, like Bohr did. All we can say is that there is a probability that the electron is in this position. So, we specify certain areas, around the nucleus, that have maximum probability of electrons existing. These areas are called orbitals. Well this is how it looks like -

                 Those circles and dumbbell shapes around the nucleus is the probability distribution of an electron being found there. They represent the highest probability of an electron being there, and not the exact position of an electron.

Look at the first picture of this article. It is the first picture taken of a hydrogen atom showing its orbitals. You can see the orbital that is circular in shape, showing that the electrons exists somewhere in that area.

The atom has now become this sea of electron probability, quite fuzzy in fact; it is all very flummoxing. 

Inside Protons And Neutrons

Well, you probably know what protons and neutrons are. They are the particles which compose the nucleus of the atom. Let us go more in depth about them 

Particularly, in the 1950s and 1960s, new subatomic particles were being discovered literally every week. There were so many like the Pi Meson, K Meson, many hadrons, and…. oh don’t get me started here. Anyway, it was a total mess, and physicists were drowning in these particles. In fact, they called it the particle zoo. Richard Feynman, is said to have remarked that the next noble prize should go to next person who does NOT discover a new particle (I should have been there; I would have got a noble prize then).

Then, the American physicist, Murray Gell-Mann, came up with the idea that all these particles are composed of a still more elementary set of particles. He called them quarks. This would mean that protons and neutrons are not fundamental, as we earlier thought them to be. 

A Recap 

OK, let us do a recap now shall we:

There is a nucleus made of protons and neutrons and electrons revolving around it.

Electrons are not as close to the nucleus as you think, there is A LOT of empty space in an atom. 

Electrons revolve in energy levels and jump form one to another.

We cannot know their position fully, only it’s probability, this make the electrons in the atom fuzzy. This is due to their wave and particle nature.

Protons and Neutrons are not fundamental, they are made of quarks.

So, NOW let’s go to something really crazy!

Playing Music On Strings

A new theory has developed in modern times: it’s called String Theory. String Theory supposes that all particles are just vibrations on a little string or rubber band. If the string is vibrated one way, it’s an electron; if it vibrates in another way, it’s a quark! It’s sorta like playing music on a guitar !

Now the catch is that, for the mathematics of string theory to work, it requires some extra dimensions. Not 4, not 5, not 6, but, 10 dimensions of Space! The strings vibrates in these dimensions and the shape of these dimensions will decide the properties of the string and therefore, the universe. 

Imagine that all electrons and protons, all atoms, and eventually us, are all vibrations on a tiny little string locked in 10 dimensions of space and one dimension of time. There's something to ponder on!

The cell is truly a near perfect piece of natural engineering. I am still incredulous at the amazing tomfoolery it undertakes to keep life ambling down its path. 

The cell is like a self-sustaining megacity; a metropolis with premium infrastructure. Everything is self-contained; it has a postal system, a government, and garbage disposal unit, all that makes a city great.

The functioning of a cell rests on five basic tenets: molecules, reactions, energy, governance and expansion. Every unicellular organism is required to fulfill all of these tasks; it is what they are built for.

Let’s look at these basic functions of a cell vis-à-vis a city and acquaint ourselves with this benign machine.

Molecules

Every city needs construction material to build its buildings and infrastructure-the buildings and roads are what define a city. In that respect, we can consider molecules as analogous to this construction material. They are akin to the concrete and steel used in modern city construction; they help to build up the infrastructure of a cell.

Just like how a city is made up of construction material, everything in a cell is made up of molecules. Molecules make up the membranes of the cells, outer covering of organelles and they are the carriers of the genetic code (which we will see a little later). A cell is composed of mainly four types of molecules: carbohydrates, lipids, proteins and nucleic acid.

Reactions

It’s not only the infrastructure that makes a city world class. One also requires people, businesses, transactions; one needs people to occupy the buildings and do work,i.e, business and economics. When the city engages in a viable business, it has a booming economy and that city comes alive.

It’s the same for a cell. For a cell, reactions are the people, the businesses, and transactions. We have all these molecules, but they need to do things, i.e., they need to react. Thus, reactions are the bedrock of the smooth functioning of a cell. They provide a means for the cell to undertake in business, and built its own viable economy.

Cells can create proteins, carbohydrates and anything else the cell is obligated to do from reactions. They serve the purpose of chemical creation and chemical transaction.

Energy

Now we’ve got a great city with infrastructure and businesses. But, what do we do when the people get hungry or when the machines-so vital for business-stop running? We provide them with energy.

In a city, we need energy to run business; in a cell we need energy to run reactions. This energy can be used to do work. The exact nature of this work can be multifarious: biosynthesis, heat production, movement of molecules. The energy can also come from various sources (depending on whether you are a plant, an animal or get your energy off of chemicals). 

Governance

In this great hypothetical city of ours, we have constituted infrastructure, business and energy. All we need now is someone or something to govern and coordinate all these undertakings en masse. In the case of a city, it is the local government; analogous to that in a cell, is the genetic information or genome. The genes of a cell have coded information for cell functioning; when it should produce a certain molecule, when it should divide, which protein goes where and so on. So, the genes are vital to the functioning of the cell.

The information is physically manifested in the form of DNA (deoxyribonucleic acid) which is coiled up in the nucleus of the cell (which is akin to the seat of governance of the city). It contains all the genes; the information necessary for the functioning of the cell. The nucleus is like the forbidden city with impenetrably high walls. Nevertheless, there are small pores for entry; and if we were to enter the nucleus via one of these pores, the sight would be addling, to say the least. It would be an utter mess of coiled up DNA molecules, indeed the whole place would be rife with DNA molecules coiled up precariously around histone proteins.

Expansion

Our city is all set to become great: it has good infrastructure, business, energy and governance. Now, if we want it to become a splendid spot on the world map, we have to make it big. The arms of the city have to expand from its tiny confines so that it can accommodate more people, more facilities and sustain large business.

The cell is the same. Only expansion in the cells case would mean reproduction. Here I use the word 'expansion' in the sense that by creating more copes of themselves, cells have an expanded reach and achieve more together. After all, many can do much more than just one. In the same way as the productivity of cities increase by expansion, so to do the productivity of cells increase when it 'expands'.

Of course, the singular purpose of life is the perpetuation of DNA; of life. In this view, reproduction or 'expansion' is much more fundamental to cell than it is to our city. Indeed, a city doesn't need to perpetuate itself!

So, the term 'expansion', could also refer to the expansion of life itself.

Other Functions

The above discussion is intended to give us a brief understanding of the cell.

But, I have a confession to make; things are not as rosy as I have portrayed them to be. It is true that the major functioning of all cells follow these five tenants. But, for cells that constitute a multicellular organism, additional tasks have to be undertaken.

They are equipped to undertake tasks that ostensibly do not benefit themselves in any manner; rather they benefit the whole organism. A muscle cell is a good example; it is built to twitch and contract on stimulation by electrical signal. Although, this purportedly does not help the functioning of a lone muscle cell; but, put many together and you’ve got a strong muscle, capable of lifting heavy weights (well, maybe not my muscles!).

Let's talk about the dark night. (NO! This post is not on Batman!).

Our common assumption is that the night sky is supposed to be dark with only few dots of light.

But then, aren't there supposed to billions upon billions of stars in the night sky emitting light. Yes, they are very far away, but, there is nothing stopping (like air or glass) the light from reaching us. So, shouldn't all those stars make the night sky (very) bright and not dark ?

This is actually called Olbers’ Paradox. 

Let's look at the problem in another way. We can divide the universe into a series of concentric shells, being 5 light years thick. Thus, a certain number of stars will be in the shell 1,00,000 to 1,00,005 light years away. If the universe is homogeneous at a large scale (i.e., static), then there would be four times as many stars in a second shell between 2,00,000 to 2,00,005 light years away.

But, the second shell is twice as far away, so each star in it would appear four times dimmer than the first shell (intensity is inversely proportional to the square of distance). Thus the total light received from the second shell is the same as the total light received from the first shell.

Thus, the argument is that if the universe were static and filled infinitely with stars, the night sky should be much brighter than it is now.

I think you guessed the loop hole here. I said if the universe were static, which it clearly isn’t.

The Big Bang explains this paradox by saying that the universe started at a point, and expanded from that point. Thus, it is not static.

We know that the expansion is accelerating. So, two things happen. 

One is that, those stars in the night sky are moving away from us and the distance between them and us increases. This increase the time for to see them and eventually it takes millions of years for the light from those stars to reach us.

Second, which is the more important reason, is that these starts get redshifted away. Redshifting is when the wavelength of an object moving away from us goes towards the red side of the spectrum and eventually, it goes into the infra red, which we cannot see. It is like we listen to a honking truck passing by at great speed. As it moves away from us, the the sound becomes softer and softer and eventually it is inaudible.