Time's Garden

“Now!” warned Later.
“No, Later!” Now stomped its foot on the ground.

They’d always been fighting. They were the kind of siblings that never saw eye to eye. They grew and they fought, they fought and they grew, and nothing their mother did could change that.

“I’m the only one that truly exists,” Now would complain.
“You’re just something that may or may not come. Why should I take you into consideration?”
“But I am your future self,” Later would counter. “If you ignore me now, you’ll be unhappy later.”
“And if I only think of you, I’ll never get to enjoy myself,” Now would cross its arms annoyed.
“How will you enjoy yourself if you know you have a million things to do?” Later would yell loudly, with its arms open wide. “How will you learn, or be, or do ANYTHING, if you just think of yourself?”

Alone in the corner, Before was rocking back and forth, its hands covering its ears. Before couldn’t stand the fights; it couldn’t stand the noise. The oldest of the siblings had seen all this way too many times before. It has been through all that before. It used to be a later that became a now, before becoming a before. As a later it had tried to reason with the then now. As a now it ignored the next later. And now it lived in disappointment and regret.

“Why should I do anything that I don’t like?” Now continued, after taking a moment to recover from the last blow. “Now is all I have, and I’m going to avoid all the discomfort I can, thank you very much.”
“A little discomfort NOW, could mean more comfort LATER,” Later said exaggeratedly slowly, as if he was talking to someone quite thick, indeed. The tone was not lost on Now, who was not impressed.

“It could also mean I’ve wasted my time being unhappy for no good reason,” Now responded, its voice dripping with sarcasm. “You can’t KNOW anything I do right now will pay off at some point. You can’t judge me for not wasting my time for a ‘maybe’!”

“But there’s NEVER absolute certainty! Would it hurt you to at least TRY from time to time?” Later exclaimed exasperated.
“And would it hurt you to stop bugging me for even a second and let me breathe?” challenged Now.

“OK, fine,” Later changed strategy abruptly. “You don’t want to do things you don’t like. What’s your excuse for not doing the things you do like? There are so many things you want to do and you always leave them for later, too. I wanna learn another language,” he said in mocking tone. “I wanna learn how to play an instrument, I wanna write a book, I wanna, I wanna, I WANNA!” Later’s voice was rising in pitch with every word, “Why don’t you do ANY of those things?” it screamed shrilly making Now cringe.

“I… I…” Now stuttered, finally at the verge of tears, “You’re asking too MUCH of me, I just want to… to… BE!” Its voice cracked and it hid its face in its hands. Later was thrown aback, but still too angry to let it go.

At that point, Time came into the room and within an instant she knew what was going on; her eyes fell on Before still rocking back and forth in the corner and Now crying defeated in its palms. Later had opened its mouth to say something, but she silenced her youngest kid with a look.
“Fighting isn’t helping anybody,” she said as she walked to the middle of the room. “Come sit with me”. She pointed to the couch. Nobody moved. She sighed and sat on the floor next to Before. It looked up at her touch, its eyes full of pain. She hugged it tight and then took it by the hand and guided it to the couch. It took a little longer to calm down Now and convince it to move, and Later, arms still crossed, was less than happy to sit next to them, but didn’t object.

Time knelt in front the three of them. “You’re all part of me. Please, be nice to each other,” she said kindly. Before looked at her lovingly, but Now and Later seemed not to care. “I know you all love each other. You just need to learn how to compromise! Later, don't bug Now all the time. Let it rest and have some fun and be a little lazy. But, also, you, Now, don't ignore Later! It's not such a big deal to get a little uncomfortable from time to time. As for you, Before, there's no reason for you to be so sad. You've had your moment and you did the best you could. Why don't you give yourself a break and give your insight to your siblings?” Time's kids were calmer now. They loved their mother and saw the wisdom in her words, after all.

“There will be a time when we’ll all be gone,” she continued. “There will be no Time; no Before, no Now, and no Later. What will your disagreements mean then? We have this one chance to make right by each other,” she smiled at them gently and they beamed back at her. “How does that sound?” she asked and they mumbled all together, “Sounds good, mom!”
“Run along and go out and play, then!” she encouraged them and so they did.

And that's how our story ends, with Before, Now, and Later laughing and playing in Time's garden...

Inspired by an upcoming med school exam, and the unwillingness of this individual to sit down and study, because her brain would much rather wander to a place far, far away; thankfully, in this galaxy, unfortunately, across an uninviting ocean.


Trivializing harassment

Sharing stories of sexual harassment makes everybody very uncomfortable. This is true for all kinds of abuse, but it’s especially so for sexual harassment. We have a history of treating victims of sexual abuse as dirty themselves, and humans have been known to shy away from discussing sexual abuse for that reason; it makes everybody feel dirty by association. This is incredibly sad and unfair, to say the least, and for the sake of our collective mental and physical well-being, we must overcome that obstacle.

As an owner of a body in a major city, I experience street harassment often. That includes cat calling, vulgar comments, whistling, attempts of toucherism, or frotteurism, and sometimes having someone follow me for a significant distance while exhibiting that behavior. I should say right off the bat tha there are many street harassment denialists out there, and this post isn’t for them.

Stop Street Harassment, commissioned a 2000-person US national survey.
The results aren't pretty. 

On a relatively recent event, I was walking on a major street in Athens, when a person started walking right next to me, trapping me between him and the buildings. I sped up automatically, and so did he to keep up and he asked if he could ask a question. I ignored him, but he asked anyway, if I’m doing sports, because I have nice body. I told him to go away and opened up my pace even more. He dropped back, but kept following me, mumbling away a stream of vulgar profanities. And so the puppy followed me for about fifteen minutes, until I reached my destination, a Starbucks.

I waited in line and ordered; all the while he was standing outside the glass doors, waiting for me to leave, but I was actually intending to sit there, anyway. He lost eye contact while I was getting my beverage, and, last I saw him, he was outside the other entrance, squinting against the sunlight and trying to find me. When I left couple of hours later, he was gone, probably having found his next target to harass.

I’m way past the point where I get surprised or upset by such incidents. I’ve been in public long enough that I have a lot worse stories to share from my and friends' experience. There is a discussion to be had about why street harassment is important, why people have the right to feel safe in public. If “civilization” means anything, it is that people should not have to be afraid for their mental and physical integrity all the time. You know, that’s what jungles are for. There is a lot of pointless obstructionism in accepting those simple facts, but, again, this is not what this post is for.

I happened to had shared that incident with some internet friends and after some time I happened to meet one of them in person. During the interaction, which was not a pleasant one for various reasons, that event was mentioned. We were discussing my habit of going to Starbucks; I explained that I relax very much there, and he said “Unless someone has followed you there”. I responded “Yeah, don’t remind me of that, it was a nightmare”. And he came back with something like “Well, the boy saw something pretty, don’t blame him for wanting it”. Taken aback, I just corrected the fact “He was no boy, more like in his late fifties”, to which he replied “So, that’s why you minded, because he was old, otherwise you would have liked it!”


I believe this person was just trying to be funny. Some people will agree with me that he failed (and exposed some deeply held stereotypical ideas in the process) while others will argue I can’t take a joke. However, that’s not the point of this post, either.

And, no, street harassment has little to do
with the amount of skin exposed
and the "provocativeness" of the outfit.
It's an act of power, control, and superiority.
As I said earlier, we generally have trouble dealing with harassment as a society. Many otherwise decent people, in their ignorance and awkwardness, can say the worst, most unempathetic comments imaginable. Two very common hurtful reactions are a) blaming the victim (It's your fault you failed to protect yourself, so don't expect us to have sympathy) and b) downplaying the significance of their experience (So, somebody grabbed your behind on the bus, big deal).

They are both quite disgusting tactics and, unfortunately, all too common. My "friend" trivialized my experience by asking me to "forgive" the harasser, because he was just a guy and I am a decent looking young female, so, of course, he can't control himself and has to harass me. You really can't get more stereotypical than that.

But there's also something else I've been thinking. I’ve spent some time trying to think the last time somebody got mugged and somebody joked “Oh come on; admit it, deep down you wanted to get mugged!” Maybe I have selective memory, but I don’t remember any such occasion. How about somebody getting beaten up for no reason by a gang? Does anybody joke “I’m sure you enjoyed it a little bit”?

I can’t think of another occasion where a person has been “attacked” in some way, reports it was against their will, reports it made them feel uncomfortable and unsafe… and it’s common for other people to casually assert that they must have liked it on some level. And yet this is so very common when it comes to sexual harassment.

That is also true, actually even more so, when it comes to men. If society has been for a long time resistant in accepting sexual harassment toward women, it’s even less open to the claims of sexual harassment that are made by men. They’re men. They always want sex. It’s only women who put the brakes on men’s lust. Men would literally put their organ anywhere. They could and would have sex with any female (remember, this is the stereotype of a cis,straight legacy). It logically follows, that it is literally impossible for a male to be sexually abused.

This view, casually sponsored by my male "friend", is not only disgusting and insulting, practically toward the whole of humanity, but it’s also simply dead wrong. Women want and enjoy sex just as much as men do, and men can very much not want to have sex on any occasion, for pretty much all the same reasons women can. This is not up to debate. It’s a biological fact.

So, there it is again; people being incapable of not enjoying a sexual interaction. If they report they didn’t enjoy it, or it was against their will, they will simply be brushed aside. “Of course you wanted it, dude. You’re a dude. Stop with the whining”. Or, in my case, if it was a "young" guy (therefore, automatically more attracting to me, according to my "friend"), I would enjoy being followed, stalked, and having vulgar comments thrown at me from a total stranger.

And so my question is…

And what is it about sexual harassment that makes so many people think the victim likes it?

I’m sure that the answer, whatever it is, will have a lot to do with a legacy of thousands of year’s worth of sexual oppression and ridiculous social beliefs, ideals, and taboos about sexuality. Well, not just about sexuality; also about how not to be a rude, unempathetic person.

So, here’s my little general piece of advice. When something hurtful happens to someone, you show sympathy and empathy, and tell them you’re sorry it happened to them. And just leave it at that. Assume the other person will not appreciate you trivializing their negative experience, unless you know them well enough to know they will.

And if you want to make jokes, make them at the expense of the perpetrators:

tea consent from Blue Seat Studios on Vimeo.


~*~ Ode to the universe ~*~

Our future might not be written in the celestial bodies
But our past certainly is

Every atom in our body, in air, water and earth,
Was forged in the hearts of old stars, long gone

And your body might only be made of those atoms
But it’s still so beautiful in its natural complexity

We might not be a special creation
But that makes everything more poetic
All life united by the same biochemistry
Painstakingly slowly changing to survive better

Your mind might only be the function of your brain
Just like all functions of our bodies arise from matter
But how does that change the richness of your emotions?
How powerful your love or hate can be for others?

And if art is not supernaturally inspired
Does that somehow negate how it touches other humans?

And while morality may not be coming from above
That only makes it so much greater
How wonderful it is, knowing it evolved,
Simply because cooperation makes life for everyone better

How does all that lessen our achievements?
In becoming more loving and more informed
In abandoning cruelty little by little
And embracing knowledge step by step

So what if we don’t have immortal souls?
Does it make this one life less wondrous or more?

The Earth might not be the center of the Universe
But it’s still as important to us as if it were

And the stars may not be telling me who you are
But they still look beautiful mirrored in your eyes.


Levels of Organization of Matter

I have tried to make this overview as precise, brief and simple as possible, but at the same time interesting to everybody, no matter your scientific and general knowledge background. It definitely wasn't an easy balance. Since we're passing over practically every science out there, making no mistakes was completely unrealistic, so I had to fight the austere perfectionist inside me to give this a shot. You might find some things difficult or some things not quite correct. If you belong to the former, don't get disappointed, the point is not to understand everything, but rather to get an idea about the structure of the Cosmos and get stimulated to learn more about it. Lots of links will redirect you to Wikipedia articles where you can read more about the various concepts discussed and at the end of the article you can find pictures for every level. If you belong to the latter, forgive my mistakes and send me some feedback about how I can make this even better, keeping in mind that the purpose of this article is not to be published in a scientific magazine. Enjoy!

1. Subatomic particle
2. Atom
3. Molecule
  3.1 Macromolecule
  3.2 Organelle
  3.3 Cell
  3.4 Tissue
  3.5 Organ
  3.6 Organ system
  3.7 Organism
  3.8 Population
  3.9 Community
  3.10 Ecosystem
  3.11 Biosphere
4. Cosmic dust
5. Accretion
6. Celestial body
7. Star system
8. Star cluster
9. Galaxy
10. Galaxy cluster
11. Universe

Matter has self-assembling properties. Here we’ll discuss the levels of its organization from the subatomic particles to the universe, even though more will probably be discovered as science progresses. Life, expressed by the levels between the macromolecules and the biosphere, is a branch of the organization of matter, since it is not necessary for the formation of the following levels. Also, this is only how life the way we know it on Earth is organized. We don't know that this is the only way "life" can be formed, as we haven't encountered any other type of life either on or off our planet. In any case, for the greater part of the universe, where there is no life, we pass from molecules directly to cosmic dust.

Elementary subatomic particles are unknown to have substructure, thus unknown to be composed of other particles. All elementary particles are, depending on their spin, either fermions or bosons. Fermions are the matter (quarks and leptons) and antimatter (antiquarks and antileptons) particles. The electron is a lepton. Bosons are “force particles”, i.e. they mediate interactions among fermions. So, fermions could be considered the structural unit of matter, while bosons are the mediators of the fundamental forces of nature (gravitational, electromagnetic, strong nuclear, and weak nuclear) that affect matter.

1a. Elementary subatomic particles included in the Standard Model.
Source: Wikipedia, Elementary particle

Combinations of elementary particles form the composite particlesProtons and neutrons are composite particles, each of them formed by three quarks, and together they form the nuclei of atoms.

1b. A proton is a composite particle
consisting of two up and one down quarks.
Source: Wikipedia, Proton
2. Atom
The atom is consisted of the nucleus and the electrons that are distributed around it. Depending upon the number of protons of the nucleus, the atom belongs to a different chemical element. Every element has its own chemical properties, which dictate the way it interacts with the other elements.

2. An illustration of the Helium atom, depicting the nucleus (pink)
and the electron cloud distribution (black).
Source: Wikipedia, Atom

The interactions of atoms lead to the formation of chemical bonds among them and the creation of a molecule. Every molecule has its own chemical properties, that result from the atoms that form it and the type of bond that connects them. This combination leads to “emergent” properties that the atoms themselves, when unbound, do not necessarily exhibit.
Molecules made of two or more different elements are called chemical compounds. Compounds that consist of any elements but carbon are called inorganic, while those that contain carbon are called organic.

3. A water molecule is made of two hydrogen and one oxygen atoms.

On certain occasions, many similar or identical compounds, the monomers, form long chains, the polymers. Organic polymers are very big molecules that exhibit, in turn, new (bio)chemical properties, like storing of information and complex and highly selective catalytic function (enzymes). Being very big, they are vulnerable and quickly split to their components when they are free in the environment. However, when they are protected, say, by a double layer of lipids, such as a cell membrane, they can persist, interact and form life, they way we know it on our planet. The macromolecules on which life depends are carbohydrates, proteins, nucleic acids and lipids (lipids are not true macromolecules, but are basic to life and are often mentioned along with the others).

3.1. DNA (deoxyribonucleic acid) is a type a nucleic acid that encodes the genetic information for the development and functioning of all known living organisms and many viruses. Here is depicted the structure of the double helix of the DNA. On the right, you can see the four monomers of the DNA, T, A, C, G.
Source: Wikipedia, DNA

The organelle is an organized collection of macromolecules and inorganic molecules within the cell that performs certain specific functions. For example, the mitochondrion is an organelle that contains macromolecules of all types, with the basic function of producing energy.

3.2 Electron microscopy of two mitochondria from mammalian lung tissue.
Source: Wikipedia, Mitochondrion

3.3 Cell
The cell is a collection of organelles and inorganic molecules (water, sodium, potassium etc) and it is the structural unit of life. It's the smallest possible entity that presents the characteristics of life and, therefore, that can be considered “alive”. Some cells constitute an organism themselves (unicellular organisms), while others live in groups (multicellular organisms).

3.3. The basic components of an animal cell.
Source: Wikipedia, Cell (biology)

3.4 Tissue
In multicellular organisms, cells can differ from each other. A group of similar cells that execute the same functions constitutes a tissue. For example, muscle tissue comprises many similar cells, the muscle cells (or muscle fibres), which have the same characteristics, including the ability to contract. The other three basic tissue types are the nerve, the epithelial and the connective tissue.

3.4. The different types of the muscle tissue.
Source: Wikipedia, Muscle tissue

3.5 Organ
The organ is consisted of cells of different tissues organized so that they can perform a complex, higher biological function. The heart, for example, contains a connective tissue “skeleton” in the shape of four rings that the heart muscle fibers attach to. The latter form four cavities that are covered internally by epithelial tissue, the endocardium. Externally, the entire heart muscle is covered by a double-walled epithelial sac, the pericardium. Within the walls of the heart there is its electrical conduction system, consisted of specialized cells that behave as both muscle and nervous tissue, which regulates the contraction of the muscle fibers. Thus, the heart functions as a pump, propelling forward the blood that enters it.

3.5. The human heart.
Source: Wikipedia, Heart

It is a group of organs that performs an even more complex biological function. The heart, a network of arterial, venous and capillary vessels, and the blood compose the cardiovascular system, which aims at the exchange of substances between every part of the body and the environment.

3.6. The human circulatory system.
Source: Wikipedia, Circulatory system

The organism is an individual, contiguous living system. It can be either uni- or multicellular. On the occasion of complex life forms, the organism is a set of organ systems that cooperate for the formation of an autonomous life form.

3.7. All organisms are classified in groups (from domains to species) based on their evolutionary relationships. Here is a speculative phylogenetic tree of life of all existent organisms based on genetic analysis.  Bacteria and archea are all unicellular, while the eukaryotes range from unicellular (such as the protozoan amoebas) to multicellular (such as all the plants and animals, including humans).
Source: Wikipedia, Organism

A group of organisms that belong to the same species.

3.8. Map of population trends of jellyfish. Red: increase (high certainty),
yellow: increase (low certainty), green: stable/variable, blue: decrease, gray: no data.
Source: Wikipedia, Population dynamics

A group of interacting organisms of different species that share the same environment.

3.9. Predation is an interspecific interaction basic to community ecology.
Source: Wikipedia, Community (ecology)

3.10 Ecosystem
A community along with the inorganic matter (soil, water, air etc) of its environment.

3.10. Nitrogen cycling in an ecosystem, containing bacteria, fungi, plants,
plant eating animals, along with inorganic materials, such as air and soil.
Source: Wikipedia, Ecosystem

3.11 Biosphere
It’s the set of all the ecosystems of the Earth (or another populated planet). Therefore, it also represents the zone of life on Earth.

3.11. This composite image gives an indication of the magnitude and distribution
of global primary production (the production of organic matter
from inorganic carbon sources) both oceanic and terrestrial.
Source: Wikipedia, Biosphere

It is a small collection of molecules that floats into space.

4. An interplanetary dust particle.
Source: Wikipedia, Cosmic dust

Dust particles, under the influence of gravity, attract each other and accumulate forming accretions.

5. Artist's conception of a black hole drawing matter
from a nearby star , forming an accretion disc.
Source: Wikipedia, Accretion disk

An accretion can be organized in a well formed celestial body. Stars are big spherical luminous celestial bodies, which produce their own light and heat. Planets are bodies that orbit a star and have enough mass so that they can obtain a spherical shape. They do not emit their own light and heat but receive these from their star. The planet we inhabit is the Earth and the star it orbits is the Sun. There are other celestial bodies, as well, such as asteroids and satellites.

6. Celestial bodies of our Solar System, including the Sun, the planets, asteroids etc.
Source: Wikipedia, Solar System model

It is consisted of a star along with the planets and the rest of the celestial bodies that are under the influence of its gravitational field. The star system of our Sun is called Solar system.

7. The orbits of the bodies in the Solar System to scale
(clockwise from top left)
Source: Wikipedia, Solarsystem

It is a group of stars, from tens to several millions, that are held together by the mutual gravitational forces. All the stars of a star cluster were born around the same period of time from the same cosmic dust.

8. The star cluster of Pleiades.
Source: Wikipedia, Star cluster

9. Galaxy
A system of millions or billions of star systems and clusters that are held together by gravitational forces forms a galaxy. The galaxy in which our solar system is found is the Milky way.

9. A fish-eye mosaic of the Milky Way arching at a high inclination across the night sky,
shot from a dark sky location in Chile.
Source: Wikipedia, Milky Way

A group of galaxies (from a few to a few thousands) that are held together by gravity comprise a galaxy cluster.

10. The Abell S740 galaxy cluster.
Source: Wikipedia, Abell_S740

All of the existent spacetime, along with all of the matter and energy that it contains, constitute the Universe.

11. Illustration of the Big bang theory, the prevailing cosmological model. In this diagram time increases from left to right, and one dimension of space is suppressed, so at any given time the Universe is represented by a disk-shaped "slice" of the diagram.
Source: Wikipedia, Universe

Explore the various levels in this wonderful interactive animation: The Scale of the Universe


Why? What is the Reason? What is the Purpose?

“Why” is the question word that asks for the “reason” behind things. However, “reason” can mean both the cause that leads to a specific outcome (Why do objects fall? Because gravity pulls them towards the earth) and the purpose behind a specific outcome that will be fulfilled after its realization (Why did you turn on the oven? Because I want to bake something).

Living organisms seem (to humans) to cause certain outcomes for a “purpose”: They move in order to find food or escape a hunter. They use special signals in order to attract the opposite sex. As they grow, they learn how certain actions lead to certain outcomes and then they do these actions with the purpose of bringing this outcome.

Bacteria phagocytosed by an amoeba 
Humans seem (to humans) to do everything with a “purpose”. They have taught themselves how to manipulate all sorts of forces around them. They put seeds in the ground and take care of the plants that grow and then harvest them, instead of looking for plants planted by “chance”, therefore that need to be stumbled upon by “chance”. They build complex structures that can explore the deep oceans, or the deep space.

But there is no “purpose” in the lightning bolt that hits the tallest tree of an area. That’s how lightning bolts are, how they work. The physics behind it dictate that the lightning bolt is created between certain regions of a cloud and of the ground that are oppositely charged. Most often, the tallest mass of the area of the ground is the one that gets hit. Clearly, there’s nothing “personal”. The lightning bolt doesn’t “choose” which tree to hit and doesn’t hit a certain tree “for a reason”.

So, the “lifeless” part of the universe doesn’t exhibit any form of “purpose”. Years and years of science show that the better we understand the world around us the better our predictions about its interactions become. And whenever something “unexplainable” by the current standards comes along, it’s just explained by a few new ideas that we hadn’t come up with until that point.

Our everyday lives haven’t really involved rain chasing a specific person or any lifeless object, defying the rules of physics for some “purpose”. We’ve dropped countless objects and yet not one has hovered to our surprise (magic tricks are only tricks on perception). The driver and the mechanics lead a car. If one “loses” control of a car, the car isn’t acting “for a purpose”.

There is “purpose” in that car accident only if someone involved acted specifically in that way with the intention to bring it about. There is something to be said about the conscious and the subconscious, but that still doesn’t bring in some higher, deeper purpose in the equation.

However, purpose, even when it comes to living creatures, is simply the rationalization our brain has created to fill in the blanks of causality. Observing a human reach for a glass of water, we might argue that the “reason”, with the meaning of “purpose”, of this action is “to drink water”. However, this simply skips the true reason, with the meaning of “cause” this time, for the action: which is, most probably, that the human is thirsty. Therefore, we have very good reasons to think “purpose”, and “reason” when it is implying “purpose”, is simply a biocentristic idea, that has evolved in the brains of a type of conscious creature, floating on a rock in the deep, cold space, otherwise devoid of any teleological “purpose”.

The pale blue dot.


The Apple Tree

Three friends are walking in the countryside. As they are approaching a big, beautiful apple tree, an apple suddenly falls from a branch to the grassy ground. They stop to look at it and one of them sighs:

“How I would like to know why the apple fell!”
The second friend picks up the apple, takes a bite, and shakes her head in appreciation:
“I’m more impressed by its taste. I want to know why it tastes like that!”
But the third one is already eyeing the tree with interest and adds thoughtfully:
“I am wondering how the apple came from the tree.”

Out of nowhere, a bunch of kids appears and, laughing and running, they cry out: “We want to know how many apples are on this apple tree!” and with lots of pushing and tagging they scramble up its bark, scatter on the branches, and start counting loudly. The friends laugh and then fall in silent contemplation. Each one observes, gropes the ground, the tree, the apple. Every now and then they exchange opinions, ask each other for new ideas, seek validation for their conclusions. Indeed, they all have useful things to say about everything, though, of course, each is more dedicated to their own quest. Occasionally, they look up and ask the kids, which keep on their merry and noisy counting, to confirm their theories.

After some time, they’ve all satisfied their curiosity. The one friend knows why the apple fell. The other has found why it tastes the way it tastes. The last one understands how the apple came to be. And the kids have counted the apples. And after a few more apple-bites under the shadow of the patient apple tree, they all continue their walk. And it’s time I introduced them to you:

The first friend is Physics.

The second is Chemistry.

The third is Biology.

And the kids… are Mathematics!


Τα επίπεδα οργάνωσης της ύλης

Προσπάθησα να κάνω αυτήν την περίληψη όσο πιο ακριβή, σύντομη και απλή γίνεται, αλλά ταυτόχρονα ενδιαφέρουσα σε όλους, ανεξαρτήτως του υποβάθρου σας στην επιστήμη και σε γενικές γνώσεις. Δεν ήταν καθόλου εύκολη ισορροπία. Καθώς περνάμε, στην ουσία, από όλες τις επιστήμες που υπάρχουν, ήταν τελείως απίθανο να μην γίνουν λάθη, οπότε έπρεπε να καταπολεμήσω την αυστηρή τελειομανή μέσα μου για να επιχειρήσω κάτι τέτοιο. Μπορεί να βρείτε ορισμένα πράγματα δύσκολα ή όχι εντελώς σωστά. Στην πρώτη περίπτωση, μην απογοητευτείτε, το νόημα δεν είναι να καταλάβετε τα πάντα, αλλά να πάρετε μια ιδέα για την δομή του Σύμπαντος και να κινητοποιηθείτε για να μάθετε περισσότερα. Πολλοί σύνδεσμοι θα σας παραπέμψουν σε άρθρα της Βικιπαίδειας, όπου μπορείτε να διαβάσετε περισσότερα για τις διάφορες έννοιες υπό συζήτηση και στο τέλος του άρθρου θα βρείτε εικόνες για κάθε επίπεδο. Στην δεύτερη περίπτωση, συγχωρέστε τα λάθη μου και στείλ’τε μου τις απόψεις σας για το πώς μπορώ να κάνω την συλλογή αυτή ακόμα καλύτερη, έχοντας στο μυαλό σας ότι ο σκοπός αυτού του άρθρου δεν είναι να εκδοθεί σε επιστημονικό περιοδικό.

Η ύλη έχει ικανότητες αυτοοργάνωσης. Εδώ θα αναφερθούμε στα επίπεδα οργάνωσής της από τα υποατομικά σωματίδια μέχρι το σύμπαν, παρ’ όλο που είναι πιθανό να ανακαλυφθούν και άλλα με την ανάπτυξη της επιστήμης. Η ζωή, που εκφράζεται από τα επίπεδα μεταξύ μεγαλομορίων και βιόσφαιρας, αποτελεί παρακλάδι στην οργάνωση της ύλης, αφού δεν είναι απαραίτητη για τον σχηματισμό των επόμενων επιπέδων. Επιπλέον, η ζωή είναι οργανωμένη με αυτόν τον τρόπο μόνο όπως την γνωρίζουμε στην Γη. Δεν γνωρίζουμε αν αυτός είναι ο μόνος τρόπος που μπορεί να σχηματιστεί η «ζωή», καθώς δεν έχουμε συναντήσει άλλο είδος ζωής πάνω στον πλανήτη μας ή έξω από αυτόν. Σε κάθε περίπτωση, στο μεγαλύτερο μέρος του σύμπαντος, όπου δεν υπάρχει ζωή, περνάμε κατευθείαν από τα μόρια στην κοσμική σκόνη.

Τα στοιχειώδη υποατομικά σωματίδια δεν έχουν γνωστή εσωτερική δομή, δηλαδή μέχρι στιγμής δεν γνωρίζουμε να αποτελούνται από μικρότερα σωματίδια. Όλα τα στοιχειώδη σωματίδια είναι, αναλόγως την ιδιοπεριστροφή τους, φερμιόνια ή μποζόνια. Τα φερμιόνια αποτελούν τα σωματίδια που σχηματίζουν την ύλη (κουάρκ και λεπτόνια) και την αντιύλη (αντικουάρκ και αντιλεπτόνια). Το ηλεκτρόνιο είναι ένα λεπτόνιο. Τα μποζόνια είναι τα σωματίδια των δυνάμεων, δηλαδή μεσολαβούν στις αλληλεπιδράσεις μεταξύ των φερμιονίων. Επομένως, τα φερμιόνια μπορούν να θεωρηθούν ως η δομική μονάδα της ύλης, ενώ τα μποζόνια ως οι μεσολαβητές των θεμελιωδών δυνάμεων της φύσης (βαρυτική, ηλεκτρομαγνητική, ισχυρή πυρηνική και ασθενής πυρηνική) που επηρεάζουν την ύλη.
Συνδυασμοί των στοιχειωδών υποατομικών σωματιδίων σχηματίζουν τα σύνθετα σωματίδια. Τα πρωτόνια και τα νετρόνια καθένα από τα οποία σχηματίζονται από τρια κουάρκ το καθένα και μαζί συνθέτουν τον πυρήνα του ατόμου.

Το άτομο αποτελείται από τον πυρήνα και τα ηλεκτρόνια που κατανέμονται γύρω από αυτόν. Ανάλογα με τον αριθμό νετρονίων και πρωτονίων του πυρήνα, το άτομο ανήκει σε διαφορετικό χημικό στοιχείο. Κάθε χημικό στοιχείο έχει τις δικές του χημικές ιδιότητες, οι οποίες καθορίζουν τον τρόπο με τον οποίο αλληλεπιδρά με τα άλλα χημικά στοιχεία.

Οι αλληλεπιδράσεις μεταξύ ατόμων οδηγούν στο σχηματισμό χημικών δεσμών μεταξύ τους και στη δημιουργία ενός μορίου. Κάθε μόριο έχει κι αυτό τις δικές του χημικές ιδιότητες, που προκύπτουν από τα άτομα που το αποτελούν και τον τύπο του δεσμού που τα συνδέει. Ο συνδυασμός αυτός οδηγεί σε «αναδυόμενες» ιδιότητες τις οποίες δεν έχουν απαραίτητα τα επιμέρους άτομα όταν είναι αδέσμευτα.
Μόρια που σχηματίζονται από δύο ή περισσότερα διαφορετικά στοιχεία ονομάζονται χημικές ενώσεις. Χημικές ενώσεις που αποτελούνται από οποιαδήποτε άλλα στοιχεία εκτός του άνθρακα ονομάζονται ανόργανες, ενώ αυτές που περιέχουν άνθρακα ονομάζονται οργανικές.
Σε ορισμένες περιπτώσεις, πολλές παρόμοιες ή ίδιες ενώσεις, που ονομάζονται μονομερή, σχηματίζουν μεγάλες αλυσίδες, τα πολυμερή. Τα οργανικά πολυμερή είναι πολύ μεγάλα μόρια που εμφανίζουν με τη σειρά τους ορισμένες νέες (βιο)χημικές ιδιότητες, όπως είναι η αποθήκευση πληροφορίας και η περίπλοκη και ειδική καταλυτική λειτουργία (ένζυμα). Τα μόρια αυτά, επειδή είναι πολύ μεγάλα, είναι και πολύ ευαίσθητα και δύσκολα επιβιώνουν ελεύθερα στο περιβάλλον. Διασπώνται γρήγορα στα επιμέρους συστατικά τους. Ωστόσο, όταν είναι προστατευμένα, όπως, ας πούμε, με μία διπλή στιβάδα λιπιδίων, την κυτταρική μεμβράνη, διατηρούνται και τους δίνεται η δυνατότητα να αλληλεπιδράσουν και να σχηματίσουν ζωή, όπως την γνωρίζουμε στον πλανήτη μας. Τα μακρομόρια στα οποία βασίζεται η ζωή είναι οι υδατάνθρακες, οι πρωτεΐνες, τα νουκλεϊκά οξέα και τα λιπίδια (τα λιπίδια δεν είναι αληθινά πολυμερή, αλλά είναι βασικά για την ζωή και συχνά αναφέρονται μαζί με τα υπόλοιπα).
Το οργανίδιο είναι μία οργανωμένη συλλογή μακρομορίων αλλά και ανόργανων ενώσεων μέσα στο κύτταρο που εκτελεί κάποιες ειδικές λειτουργίες. Για παράδειγμα, το μιτοχόνδριο είναι ένα οργανίδιο που περιέχει διάφορα μακρομόρια όλων των κατηγοριών και η βασική του λειτουργία είναι η παραγωγή ενέργειας.
Το κύτταρο είναι μία συλλογή οργανιδίων και ανόργανων μορίων (νερό, νάτριο, κάλιο κλπ) και είναι η δομική μονάδα της ζωής. Είναι, δηλαδή, η μικρότερη δυνατή οντότητα που παρουσιάζει τους χαρακτήρες της ζωής και άρα που μπορεί να θεωρηθεί «ζωντανή». Ορισμένα κύτταρα αποτελούν από μόνα τους έναν οργανισμό (μονοκύτταροι οργανισμοί), ενώ άλλα συνθέτουν συναφείς ομάδες (πολυκύτταροι οργανισμοί).
Στους πολυκύτταρους οργανισμούς, τα κύτταρα μπορεί να διαφέρουν μεταξύ τους. Μία ομάδα όμοιων κυττάρων που εκτελεί συγκεκριμένες λειτουργίες αποτελεί ένα ιστό. Για παράδειγμα, ο μυϊκός ιστός αποτελείται από πολλά όμοια κύτταρα, τα μυϊκά κύτταρα (ή μυϊκές ίνες), τα οποία έχουν τα ίδια χαρακτηριστικά, συμπεριλαμβανομένης της ικανότητας να συστέλλονται. Άλλοι ιστοί είναι ο νευρικός, ο επιθηλιακός και ο στηρικτικός ιστός.
Ένα όργανο αποτελείται από κύτταρα διαφορετικών ιστών, οργανωμένα έτσι ώστε να εκτελούν μία σύνθετη, ανώτερη βιολογική λειτουργία. Η καρδιά, για παράδειγμα, αποτελείται από έναν «σκελετό» στηρικτικού ιστού σε σχήμα τεσσάρων δακτυλίων, στους οποίους προσφύονται οι καρδιακές μυϊκές ίνες. Αυτές σχηματίζουν τέσσερις κοιλότητες που εσωτερικά καλύπτονται από ειδικό επιθηλιακό ιστό, το ενδοκάρδιο. Εξωτερικά, όλος ο μυς της καρδιάς καλύπτεται από ένα διπέταλο επιθηλιακό σάκο, το περικάρδιο. Μέσα στα τοιχώματα της καρδιάς βρίσκεται ένα σύστημα ηλεκτρικής αγωγιμότητας που συνίσταται από εξειδικευμένα κύτταρα με χαρακτηριστικά τόσο μυϊκού όσο και νευρικού ιστού, το οποίο ρυθμίζει τη συστολή των μυϊκών ινών. Η καρδιά, έτσι, λειτουργεί ως αντλία προωθώντας το αίμα που εισέρχεται σε αυτή.
Είναι μια ομάδα οργάνων που εκτελεί μία ακόμη πιο σύνθετη βιολογική λειτουργία. Η καρδιά, ένα δίκτυο αρτηριώνφλεβών και τριχοειδών αγγείων, και το αίμα συνθέτουν το καρδιαγγειακό σύστημα, το οποίο έχει σκοπό την ανταλλαγή ουσιών μεταξύ κάθε σημείου του σώματος και του περιβάλλοντος.  
Ο οργανισμός είναι μία ξεχωριστή, συναφής μορφή ζωής. Μπορεί να είναι είτε μονοκύτταρος είτε πολυκύτταρος. Στην περίπτωση σύνθετων μορφών ζωής, ο οργανισμός είναι ένα σύνολο οργανικών συστημάτων που συνεργάζονται προς  το σχηματισμό μιας αυτόνομης μορφής ζωής.
Πληθυσμός είναι μία ομάδα οργανισμών που ανήκουν στο ίδιο είδος.
Κοινότητα είναι μια ομάδα αλληλεπιδρώντων οργανισμών που ανήκουν σε διαφορετικά είδη και μοιράζονται την ίδια περιοχή.
Οικοσύστημα είναι μία κοινότητα μαζί με την άβια ύλη (γη, νερό, αέρας κλπ) εντός της περιοχής.
Είναι το σύνολο όλων των οικοσυστημάτων της Γης (ή άλλου κατοικημένου πλανήτη). Επομένως, αντιπροσωπεύει επίσης την ζώνη της Γης που φιλοξενεί τη ζωή.
Είναι μικρές συλλογές μορίων που αιωρούνται στο διάστημα.

Σωματίδια σκόνης κάτω από την επίδραση της βαρύτητας έλκονται και συσσωρεύονται σχηματίζοντας συσσωματώσεις ύλης.

Μία συσσωμάτωση της ύλης μπορεί να οργανωθεί σε ένα καλά σχηματισμένο ουράνιο σώμα. Τα άστρα είναι μεγάλα σφαιρικά ουράνια σώματα που είναι αυτόφωτα, δηλαδή παράγουν δικό τους φως και δική τους θερμότητα. Οι πλανήτες είναι σώματα που περιφέρονται γύρω από ένα άστρο και έχουν αρκετή μάζα ώστε να αποκτήσουν σφαιρικό σχήμα. Είναι ετερόφωτοι, δηλαδή δεν παράγουν φως και θερμότητα, παρά μόνο τα δέχονται από το άστρο τους. Ο πλανήτης που κατοικούμε είναι η Γη και το άστρο γύρω από το οποίο περιφέρεται είναι ο Ήλιος. Υπάρχουν και άλλα ουράνια σώματα, όπως οι αστεροειδείς και οι δορυφόροι.

Αποτελείται από ένα άστρο μαζί με τους πλανήτες και τα λοιπά ουράνια σώματα που βρίσκονται υπό την επίδραση του βαρυτικού του πεδίου. Το αστρικό σύστημα του Ήλιου μας ονομάζεται Ηλιακό σύστημα.

Είναι μία ομάδα άστρων, από δεκάδες μέχρι μερικά εκατομμύρια, που συγκρατώνται μεταξύ τους λόγω των αμοιβαίων βαρυτικών έλξεων. Όλα τα άστρα ενός αστρικού σμήνους γεννήθηκαν την ίδια περίοδο από την ίδια αστρική σκόνη και το καθένα έχει το δικό του αστρικό σύστημα, με τους πλανήτες, τους αστεροειδείς του κλπ

Ένα σύστημα εκατομμυρίων ή δισεκατομμυρίων αστρικών συστημάτων και σμηνών που συγκρατούνται μεταξύ τους μέσω βαρυτικών δυνάμεων καλείται γαλαξίας. Ο Γαλαξίας στον οποίο ανήκει το ηλιακό μας σύστημα γράφεται με κεφαλαίο, καθώς θεωρείται κύριο όνομα.

Μία ομάδα γαλαξιών (από μερικούς μέχρι χιλιάδες στον αριθμό) που συγκρατούνται μεταξύ τους μέσω της βαρύτητας αποτελούν ένα σύμπλεγμα γαλαξιών.

Όλος ο υπάρχων χωροχρόνος, μαζί με όλη την ύλη και ενέργεια που περιλαμβάνει, αποτελεί το Σύμπαν.

Περιηγηθείτε στα διάφορα επίπεδα με αυτήν την υπέροχη διαδραστική απεικόνιση: Η κλίμακα του σύμπαντος

1α. Τα στοιχειώδη υποατομικά σωματίδια που περιλαμβάνονται
στο Καθιερωμένο Πρότυπο.
Πηγή: Wikipedia, Elementary particle
1β. Το πρωτόνιο είναι σύνθετο σωματίδιο που αποτελείται
από δύο «πάνω» και ένα «κάτω» κουάρκ
Πηγή: Wikipedia, Proton
2. Αναπαράσταση του ατόμου του Ηλίου, όπου απεικονίζεται
ο πυρήνας (ροζ) και το ηλεκτρονιακό νέφος (μαύρο-γκρι)
Πηγή: Wikipedia, Atom
3. Ένα μόριο νερού αποτελείται από δύο άτομα υδρογόνου και ένα οξυγόνου.
3.1. Το DNA (δεοξυριβονουκλεϊκό οξύ) είναι ένα είδος νουκλεϊκού οξέος που κωδικοποιεί την γενετικές πληροφορίες για την ανάπτυξη και λειτουργία όλων των γνωστών ζωντανών οργανισμών και πολλών ιών. Εδώ απεικονίζεται η δομή της διπλής έλικας του DNA. Δεξιά, μπορείτε να δείτε τα τέσσερα μονομερή του DNA, T, A, C, G.
Πηγή: Wikipedia, DNA
3.2 Ηλεκτρονική μικροσκόπηση δύο μιτοχονδρίων από πνευμονικό ιστό θηλαστικού.
Πηγή: Wikipedia, Mitochondrion
3.3. Τα βασικά συστατικά ενός ζωϊκού κυττάρου.
Πηγή: Wikipedia, Cell (biology)
3.4. Τα διαφορετικά είδη μυϊκού ιστού.
Πηγή: Wikipedia, Muscle tissue
3.5. Η ανθρώπινη καρδιά.
Πηγή: Wikipedia, Heart
3.6. Το ανθρώπινο κυκλοφορικό σύστημα.
Πηγή: Wikipedia, Circulatory system
3.7. Όλοι οι οργανισμοί ταξινομούνται σε ομάδες (από επικράτειες μέχρι σε είδη) με βάση την εξελικτική τους σχέση. Αυτό είναι ένα υποθετικό φυλογενετικό δέντρο της ζωής όλων των υπάρχοντων οργανισμών βάσει γενετικής ανάλυσης. Τα βακτήρια και τα αρχαία είναι όλα μονοκύττρα, ενώ οι ευκαρυωτικοί κυμαίνονται από μονοκύτταροι (όπως είναι τα πρωτόζωα αμοιβάδες) ως πολυκύτταροι (όπως είναι όλα τα φυτά και τα ζώα, συμπεριλαμβανομένου και του ανθρώπου).
Πηγή: Wikipedia, Organism
3.8. Χάρτης της τάσης του πληθυσμού των  τσουχτρών. Κόκκινο: αύξηση (υψηλή βεβαιότητα),
κίτρινο: αύξηση (χαμηλή βεβαιότητα), πράσινο: σταθερός/κυμαινόμενος, μπλε: ελάττωση, γκρι: έλλειψη δεδομένων.
Πηγή: Wikipedia, Population dynamics
3.9. Η θήρευση είναι μία βασική διαειδική αλληλεπίδραση στην οικολογία μιας κοινότητας.
Πηγή: Wikipedia, Community (ecology)
3.10. Ο κύκλος του αζώτου σε ένα οικοσύστημα που περιλαμβάνει βακτήρια, μήκυτες, φυτά, φυτοφάγα ζώα μαζί με ανόργανα υλικά όπως αέρα και χώμα.
Πηγή: Wikipedia, Ecosystem
3.11. Αυτή η εικόνα δείχνει το μέγεθος και την κατανομή της παγκόσμιας πρωτογενούς παραγωγής (της παραγωγής οργανικής ύλης από ανόργανες πηγές άνθρακα), τόσο στους ωκεανούς όσο και στη στεριά.
Πηγή: Wikipedia, Biosphere
4. Ένα σωματίδιο διαπλανητικής σκόνης.
Πηγή: Wikipedia, Cosmic dust
5. Καλλιτεχνική σύλληψη μιας μαύρης τρύπας που έλκει ύλη από ένα κοντινό άστρο,
με αποτέλεσμα τον σχηματισμό ενός δίσκου επαύξησης.
Πηγή: Wikipedia, Accretion disk
6. Τα ουράνια σώματα του Ηλιακού μας Συστήματος, συμπεριλαμβανομένου
του Ήλιου, των πλανητών, των αστεροειδών κλπ.
Πηγή: Wikipedia, Solar System model
7. Οι τροχιές των σωμάτων του Ηλιακού Συστήματος σε κλίμακα
(με την κατεύθυνση του ρολογιού από πάνω αριστερά)
Πηγή: Wikipedia, Solarsystem
8. Το αστρικό σμήνος των Πλειάδων.
Πηγή: Wikipedia, Star cluster
9. Μωσαϊκό με την φωτογραφική τεχνική «μάτι του ψαριου» του Γαλαξία
να σχηματίζει αψίδα στον νυχτερινό ουρανό. Λήψη από σκοτεινό μέρος στην Χιλή.
Πηγή: Wikipedia, Milky Way
10. Το σμήνος γαλαξιών Abell S740.
Πηγή: Wikipedia, Abell_S740
11. Απεικόνιση της Θεωρίας της Μεγάλης Έκρηξης, που είναι το επικρατούν κοσμολογικό μοντέλο. Στο διάγραμμα αυτό ο χρόνος αυξάνεται από αριστερά προς τα δεξιά και μία διάσταση του χώρου έχει συμπιεστεί, έτσι ώστε σε κάθε δεδομένη χρονική στιγμή το Σύμπαν να αντιπροσωπεύεται από μία τομή σε σχήμα δίσκου.
Πηγή: Wikipedia, Universe