Reality of Double-Slit Experiment

More than two hundred years have passed since Thomas Young performed the famous double-slit experiment as a demonstration of the wave behavior of visible light, and still its revelation has puzzled our sanity ever since. In short, if we shoot a beam of light at a panel with two small slits (less than a millimeter apart), the photons—elementary particles that light is made of—have to figure out how to get through the slits to radiate out the other side. If they were truly particles, like in the macro world, they would project a solid image of two piles on the background wall behind the slits. If they travel similarly to the waves, like water does in the macro world, the image would resemble a wave-like interference pattern: alternating locations, equidistantly spaced, where particles leave a mark on the wall.

Thanks to the outcome of the experiment, we know that light is capable of doing both. It always travels in a wavelike fashion, even if we shoot photons in a row towards slits, one after another. The quantum mechanics explanation is that photons are in superposition, meaning they can exist in different states and even multiple places at the same time. The weirdness comes 'only' if we try to tag particles with pass-through detectors in order to detect which slit they are choosing to go through. At that instant, they break superposition and continue to travel as macro-objects, just like bullets.

This is very similar to the coin flipping or well-known Schrödinger's cat from the macroworld analogy. If we use quantum terminology, these two are in a simple binary superposition; they both have only two outcomes, the coin ending either head or tail or the cat's version being either dead or alive. Superposition in a double-slit experiment is way more complex as far as the photons being in multiple places at the same time between the slits and the detection wall.

However, the weirdness is only present at the quantum level of the microworld, and in the case of light in the double-slit phenomenon, the puzzle is not the nature of how light travels but rather why it behaves the way it does in the moment of being observed. Certainly, it creates profound questions for which we still have no definite answers. The most interesting one is, did we find the puzzle here that shows us how nature really works? What is the reality behind the engine in the quantum world? More important is even the question: is this reality objective throughout the universe, or is it subjective and created for the observer only?

Let's think about the reality problem for the moment first. This behavior of breaking superposition for the sake of the observer is very reminiscent of graphically demanding video games in which the reality is never objective—the scenes are always rendered for the gamer's sensory inputs. If you play those kinds of games and decide to enter a closed room through the door, the room and everything in it don't exist at all until you open the door. Only then does the CPU start creating it for you, and there's a certain superposition of the room and your actions in it that breaks to only one outcome, depending on what you do.

Now, double-slit is too complex to test it this way, but binary superposition could be simple enough to create in the lab in quantum equivalent and monitor what happens. This is what the experiment made by Massimiliano Proietti and his team at Heriot-Watt University in Edinburgh tried to perform on a small-scale quantum computer made up of three pairs of entangled photons. The idea is to experimentally test Wigner's thought experiment of an observer of the quantum outcome being also observed by a second observer. The resulting statements of the two observers are that their interpretations of the outcome contradict each other. The same happens in the lab, with entangled photons in the role of non-conscious observers—the inequality in the data is definitely violated, which points in the direction that quantum mechanics might indeed be incompatible with the assumption of objective facts. To put it simply, multiple observers of the same event can have different outcomes as the process in superposition breaks in different patterns. Just like in video games, the reality of nature could also be subjective and rendered for the observer's eyes only.

Of course this raises more questions, and the main one is what "observation" and "observer" really mean. In quantum mechanics, an observation is defined as the interaction of two quantum states that can collapse each other’s probability wave function. In one way or another, this also means that by observing something, we disturb it to the point of ruining the process we are trying to understand. If we add a philosophical point of view, we can also ask ourselves, does consciousness play a role in the observation process? There's an interesting philosophical thought experiment starting with the question, "If a tree falls in a forest and no one is around to hear it, does it make a sound?" followed by "Can something exist without being perceived by consciousness?"

Well, if you ask me, consciousness or not, if we go this path with reflection to the original double-slit experiment, it is all going toward the direction that the unobserved world only exists in a sort of superposition state, all possibilities of all possible outcomes only waiting for an observer to disrupt it to the point of the ultimate collapse as the result of the reaction between the two processes and the observer. The light is no different; its wave-like behavior is its own superposition, only waiting for somebody to play with. Preferably with lasers and Lego cubes, just like in the above YouTube video. Science is fun, perhaps because it is so mysterious from occasion to occasion. I know I had tons of fun creating this video with my son a couple of years ago. Please find more stories within the physics thread of the blog in the below link.

Strange world of physics at MPJ:
https://www.mpj.one/search/label/physics

Science refs:
https://www.youtube.com/watch?v=h75DGO3GrF4
https://en.wikipedia.org/wiki/Wigner%27s_friend
https://phys.org/news/2019-11-quantum-physics-reality-doesnt.html
https://arxiv.org/abs/1902.05080

Quantum Weirdness

Rarely do I get a chance and a real opportunity to revive an old article from the past and to update it to fit better in the present day. Actually, the quantum weirdness is still where it was four years ago—science is not something that changes overnight, especially with quantum mechanics, so I am not going to update the post with any new physics or breakthroughs. Instead, what's new and what pushed me to repost today is one extraordinary novel in the field. The book that kept me from sleeping last weekend was "Quantum Space" by Douglas Phillips, and in short, it is by far one of the best titles I read this year. It is one of those true sci-fi stories that follows the real science and, in this case, the weirdness of the quantum world I wrote about in this post, and I would add it is one of those articles I enjoyed writing the most in the history of the blog. But, before a couple of my glimpses at the book itself, followed by my warm recommendation, and especially if you want to read it yourself, please continue reading about physics itself. This one definitely requires some knowledge to understand it fully, so let's start with some weirdness of our own macrophysics first.

It's very well known that the world we live in is driven by two sets of rules, or physical laws. The one for big and the one for small. We don't need to be rocket scientists in order to observe our big world surrounding us and to notice all the laws we obey. For example, if we drop a book and a feather and let them both hit the floor separately, it is obvious that the book touches the floor first. However, if we put a feather ON the book and let them fall together, they will hit the carpet at the same time. Well, the book will still hit the carpet first, but if you try the experiment, you will know what I mean. This simple experiment was itching Galileo's mind centuries ago when he discovered one of the fundamental physics laws stating simply that the mass of the object has no influence on the speed of free falling. But we can ask ourselves next, why did the feather travel slower toward the floor if dropped alone? Because of the things we cannot see. The air is blocking it. To learn what is happening with the feather during the fall, we have to go beyond our eyes. We need science and experiments to discover why small molecules of the air would rather play with feathers than with heavy books.

Was the book/feather experiment weird to you? I am sure it was at least a little weird if you were seeing it for the first time. We simply accept things for granted. What we cannot see, like the air and its little ingredients in the above experiment, we tend to exclude from our perception. If this was a little strange and intriguing, let's go further to the world of the even smaller and compare it to the world of the big. For example, in a mind experiment, we have a 9mm gun and shoot toward the wall with two holes in it, both with a diameter of 9mm or a little bigger. If you are an Olympic champion in shooting, you will, of course, need only two bullets, one for each hole. In the world of little, if we use a gun that shoots electrons toward a wall with two adequate holes in it, you would probably think that we would need two electrons to hit both holes, right? Nope, we need only one. Believe it or not, one electron goes through both holes, and we don't even need to aim too perfectly. No, it doesn't split up in two and use each half to pass the holes. It goes through both holes at the same time. In fact, if we had three or more holes on the wall, one single electron would go through each one and, at the same time, use all possible paths toward the destination. Perhaps the best illustration of what happens in this experiment is presented by the "Stephen Hawking's Grand Design" documentary made by Discovery Channel.

And you thought the feather on the book was weird...

However, this is just another interpretation of the famous double-slit experiment, and even though the first theories about the duality of particles/waves originated way back with Thomas Young and his scientific paper about the properties of light in 1799, perhaps the best-known theory was proposed by Richard Feynman during the forties of the 20th century. The beginning of the last century will be remembered by the birth of quantum mechanics, part of the physics trying to describe all the laws responsible for what is happening in the inner world, or the world where the very fabric of our universe is located. Feynman confirmed Young's light theory that subatomic particles (as we call them today) and energy waves are more or less the same. Electrons are among them. In simple words, they are capable of traveling as particles (and acting as bullets in our giant world by traveling within the straight line from point A to point B) or avoiding obstacles by transforming into waves and vice versa. However, after all these years, due to the fact that we are way too big to monitor the quantum world directly, we still have no clue why and how subatomic particles choose to travel either as a wave or as a particle of the material world. For example, in a previous double-slit experiment, if we tried to add a source of photons and "light" the holes where electrons are "passing through", trying to find out what happens on the surface of the wall and how they "choose" to be either particles or waves, we only added disturbance in the system, and electrons simply stopped transforming into waves and started going through the holes like simple bullets, with many of them crashing into the wall in case of missing the holes. It's almost like they know that somebody is watching them and that they don't like to expose their secret of how they vanish into thin air, forming waves and materializing back after the wall. That skill would be something special in every magician's performance.

Feather experiment on the Moon, by Apollo 15's commander David Scott

As you probably noticed, this post is part of the "Beth's Q&A" thread, and even though quantum mechanics is not directly mentioned in Beth's and my chats, it is simply not possible anymore to stay with the standard or particle model of mainstream physics and to look to the inner world only by researching its particle-type properties. Like with me and possibly with many scientists out here (and to be fair, I am not the scientist, just a modest observer), a set of laws responsible for the entire microscopic world seems to be "under construction" today more than ever. The idea for this post came to me a couple of months ago, when Beth asked me exactly this: "Somewhere, sometime, someone figured out the inside of the atom. Quarks, they call them. What we used to call the proton and nucleus of the atom. Why can't we still call them as before? Why did a new name come into play? Who discovered quarks, and how? Did they use the electron microscope? Did they use math? Tell me what you know of quarks. How did that come about? I am interested in the electron microscope and quarks or anything else hiding in an atom. The item that was never to be broken down, as it was taught to me".

Quarked! - How did the quarks get their names?**

Before we dive into more weirdness of the quantum world, let's check a little current terminology regarding atoms with all their parts, including quarks as the smallest items within. The word "átomos" originates from the Greek word ἄτομος, and it was made by Democritus, an ancient Greek philosopher who, around the year 450 BCE, formulated the first atomic theory, or the nature of matter we are made of. Translated from Greek, "atom" means something basic and uncuttable into smaller pieces. Almost two millennia passed since Democritus, and finally, in the year 1911, it was discovered that an atom, after all, is made of even smaller particles. Ever since then, we know that an atom is now made of a nucleus with a positive electric charge surrounded by a cloud of negatively charged electrons orbiting the nucleus. The smallest atom is the simplest isotope of hydrogen-1, with a nucleus of just one proton orbited by one electron. The heaviest atom made by nature found on Earth is Plutonium-244, the most stable isotope of Plutonium, with 94 protons and 150 neutrons in its nucleus and a cloud of 94 electrons in the orbit. For 50 years, protons, neutrons, and electrons were the tiniest particles known to the world. Then in the year 1968, the very year when I was born, experimental physicists at the Stanford Linear Accelerator Center confirmed the existence of 6 different types of quarks. Much like electrons, they have various intrinsic properties, including electric charge, color charge, mass, and spin. Two of them with the lowest mass are the most stable, and they are simply called Up and Down. Scientists are not very intuitive when it comes to naming stuff—the other four quarks are called Strange, Charm, Bottom, and Top. I wonder how exactly one of them behaved in Accelerator's results in order to get the name 'Charm'. On the other end, I like this much more than naming scientific stuff with only Greek letters. Anyway, within the standard model of particle physics, quarks are building blocks in the universe, and many particles are made out of quarks. Quarks can't live in solitude, only in combination with other quarks, and they are tied up with a strong nuclear force, which is extremely hard to break. A proton is made of two up quarks and one down quark, while a neutron is a combination of two down quarks and one up quark. They orbit around each other and form an entity we call a particle. The bottom line now is that, as far as we know, quarks and electrons are fundamental particles, and we don't have any proof that they are made out of even smaller internal structures.

However, we have a pretty good idea what's inside. Strings. Now comes the part of real weirdness. Are you ready to dive into a rabbit hole? It will not lead you into Wonderland, but it is certainly one of the biggest scientific adventures.

Stephen Hawking, Grand Design***

Actually, it's not easy to describe what strings are in scientifically popular terms, but I will try anyway. In the standard model, besides six quarks and an electron, there are more fundamental particles. There are two more particles with negative charges similar to electrons called 'muons' and 'tauons.' Compared to electrons, they are much heavier in size (if we can speak about size when it comes to fundamental particles). Finally, there are three types of neutrinos, or particles that are neutral in electric charge. So far, we have encountered 12 fundamental particles. But there are more. As far as we know today, there are four fundamental forces as well (gravity, electromagnetism, and the weak and strong nuclear forces), and each force is produced by fundamental particles that act as carriers of the force. The photon is, for example, a carrier for electromagnetism; the strong force is carried by eight particles known as 'gluons'; the weak force uses three particles, the W+, the W-, and the Z; and finally, gravity is supposed to be taken care of by the fundamental particle called 'graviton'. Standard model predicted existence of all these fundamental particles, including Higgs boson we talked about last year in post Beth's Q&A - The God Particle. Each one except for the graviton. All efforts to include gravity in the theory so far have failed due to difficulties in describing it on a great scale within quantum mechanics. Step by step, over the years, new theories arrived, tending to fill in the blank or to replace the standard model entirely. There are several string theories that are 'under development', with the best candidate called 'M-theory', formulated in the last decade of the last century. In short, strings are single-dimensional objects we find within fundamental particles, or, to be precise, particles are nothing more than just different manifestations of the string. Strings can move and oscillate in different ways. If it oscillates a certain way, then its name is electron. If it oscillates some other way, we call it a photon, or a quark, or a neutrino, or... a graviton. In a nutshell, if string theory is correct, the entire universe is made of strings! However, the mathematical model of a string theory, such as M-theory, is far more complex than we can possibly imagine. Even though string theory can be seen as an extension to the standard model, its background is far more different than with the universe described by the particle model. Compared to the space-time continuum we live in as a four-dimensional universe described by the standard model, in M-theory there are 7 dimensions more. Those dimensions are tiny and undetectable by big objects like us living in large three-spatial dimensions, but within the quantum world there are objects capable of spreading their existence and occupying up to 9 dimensions. Furthermore, the theory predicts that additional tiny dimensions can be curved in a large number of ways, and even a slightly different position or curvature of at least one dimension would lead to dramatic changes of the whole system or entire universe. For example, if somehow we forced one dimension to curve a little bit more, the effect could, for instance, be different oscillations of strings, which would result in slightly different properties of fundamental particles, and electrons could start behaving differently and start having different electric charges. This example is highly speculative, but the point is that with different shapes of dimensional systems, the set of physical laws in the system would be completely different.

To put it simply, if laws of the universe can be changed by, for example, God, and if string theory in the form of M-theory is correct, he would do that by some almighty computer capable of curving dimensions. A combination of changes in the curvature of miniature 7 dimensions could be able to change, for example, the value of pi, and instead of being 3.14159265359..., it could be a different number. It is unknown what that would mean further, but in the universe where pi is, for example, 5, the circle would be something entirely different, and the pupils in schools learning about it would probably look very different than in our universe. However, there is still no direct experimental evidence that string theory itself is the correct description of nature and the true theory of everything most scientists dream of.

Completing superstring theory

But if laws of the universe after creation are unchangeable (not even by the gods) and if M-theory is true, is it possible that some natural phenomenon exists out there capable of giving birth to different universes by randomly producing the shape of their inner cosmos? Yep, there is one. Appropriately called "The Big Bang". The moment of creation of everything we are familiar with, including time. In the first couple of moments, when the process was very young, we can safely say that it all worked completely under the quantum mechanics and laws of the microcosmos, and it is not far from common sense to expect that, like in a double-slit experiment, all particles during the first moments of their existence used all possible paths in their travel toward the final destination. Within M-theory, this might mean that all possible versions of universes emerged as the result, and the one we exist in is just one of many. Furthermore, theory also predicts that within one universe all positive energy (planets, stars, life, matter, and antimatter in general) is balanced by the negative energy stored in the gravitational attraction that exists between all the positive-energy particles. If this is correct, then the total energy within one universe might be zero and therefore possible to be created out of nothing only by quantum fluctuations of the primordial singularity. Quantum fluctuations are a very well-known phenomenon that is experimentally confirmed in the form of virtual particles that arise from vacuum (particle-antiparticle pairs) and cancel each other almost immediately (unless this happens on the event horizon of a black hole, where one of the particles was immediately captured by the black hole, leaving the other alive in the form of Hawking radiation).

I am sure that 'M-theory' will stay just a theory for many more years to come, as proving the existence of strings, multi-dimensions, multi-universes, supersymmetry, etc. must be very hard with our current technology, but theories improve over time as well as technology, and perhaps we will have our answer relatively soon. However, the quantum world with all its weirdness is very much real, and many predictions, no matter how strange, are already proven. For example, quantum entanglement on top of it. This is the ability of two particles (or more) that usually originate from the same source to have the same properties like momentum, spin, polarization, etc., so that even after they are separated in space, when an action is performed on one particle, the other particle responds immediately. This was experimentally confirmed with two photons separated by 143 kilometers across two Canary Islands and soon should be used in an experiment between the ISS and Earth in the form of a first wireless Quantum Communications Network and for the first time perform the connection between two points separated by more than 400 km.

D-Wave quantum computer

Finally, let's just mention one potential application of quantum superposition (the ability of a particle to exist partly in all its particular theoretically possible states simultaneously). Compared to a digital computer, where one bit can hold information in the form of either 0 or 1, one qubit (quantum computer alternative) can hold either 0, 1, or anything in between at the same time. The idea is to use this property and build a quantum computer capable of performing millions of operations at the same time. Still in the early years of development and far before commercial use, quantum computers with up to 512 qubits developed in D-Wave, one of the leading companies dedicated to the future quantum computer market is making chips specially manufactured for quantum computation. Maybe it is still too early to say, but I have a feeling that quantum mechanics is mature enough and ready for practical applications, especially in the field of communications and IT. Along with nanotechnology, this would someday in the near future be one of those truly breakthrough discoveries capable of changing the world entirely.

At the very end, let me continue the story with a few short notices about "Quantum Space", amazing science fiction by Douglas Phillips and his first novel in the series. If you read the entire post and didn't have much knowledge about the science itself, I am sure by now you are better prepared to read the book and enjoy it much more. Of course, Douglas did a pretty good job with his characters explaining the science as well, perhaps on a much better level than I did, so there are no worries about understanding the quantum mechanics to follow the book. Much of it is still the unproven theory, so it's harder to distinguish science from fiction anyway. Nevertheless, for the fiction as far-fetched as it is, and even though the theory is weird by its nature, I found it to be, well, believable is maybe not the right word, but definitely intriguing. I loved the idea of expanding the microdimension and the way of solving the Fermi paradox within the storyline. The characters and the writing are also great, so in all the effort to write spoilerless reviews, all I can say is that I will eagerly wait next year for the sequels.

Image ref:
https://futurism.com/brane-science-complex-notions-of-superstring-theory/

Quantum Space
http://douglasphillipsbooks.com/books

*Stephen Hawking's Grand Design: Action of Electrons
http://www.discoveryuk.com/web/stephen-hawkings-grand-design-action-of-electrons

** Quarked!
http://www.quarked.org/askmarks/answer24.html

*** Stephen Hawking and Leonard Mlodinov: The Grand Design
http://www.amazon.com/The-Grand-Design-Stephen-Hawking/dp/055338466X
http://www.amazon.com/Velika-zamisao-Stiven-Hoking/dp/4095178361 (serbian edition)

Refs:
http://www.wikihow.com/Calculate-Average-Velocity
http://pratthomeschool.blogspot.com/2010/10/geometry-lesson.html
http://www.superstringtheory.com/
http://www.nuclecu.unam.mx/~alberto/physics/string.html
http://www.zmescience.com/science/physics/physicists-quantum-photons-08092012/
http://www.zmescience.com/science/physics/quantum-entanglement-iss
http://www.discoveryuk.com/web/stephen-hawkings-grand-design/videos/
http://en.wikipedia.org/wiki/Double-slit_experiment

Déjà vu

In the writers' world, titles are extremely important. If they are strong enough, the stories are practically writing themselves. So to speak. According to MarketingProfs research, more than 2 million articles, posts, and stories are published online every day, and lots of people read no further than the title. Opening lines capable of forcing you to perform the actual click are nowadays a rarity, and I am not talking about those behind daily politics and current worldwide affairs. It's about all those titles that don't expire with the next election or season. I am talking about all those powerful enough to coin new words.

The one on today's menu is exceptional. Simply, "Déjà vu" has it all, with the potential of diving into the mysterious and unexplored world of the human brain. It always comes with a great glimpse into fabulous quantum mechanics we are still pioneering to understand, tons of speculations of various kinds, including spiritual experiences, subconscious networks of living beings, bugs in divine intelligent design, telepathic experiences... You name it. But I'll stop right here because this post is not going to be about speculations. It will be just a teaser of my hopefully rational but also skeptical mind. Also, a couple of theories as well.

But, let me start with my first and probably the strongest déjà vu I still remember a vivid scene from yesterday's movie I watched on cable. Hmm, "cable", an interesting word, as this was exactly what I was doing when it happened. The year was 1985, and I was the main technician in the school play back in my early days of high school. It was probably the best year of my school days thanks to this play because it lasted a couple of months during winter, and we were extremely enthusiastic about it, and there were lots of stories left from that period of us growing up. Well, in short, I was mounting cables on the stage for the borrowed, old-fashioned even for that year, tape player, as I was the one who was in charge of audio effects for the play, and in a brief moment I glimpsed the scene: two actors rehearsing the main dialogue, and in the background I could see a couple of the first rows of the school's musical hall with our teacher sitting in the first row and a couple more viewers and friends watching from the back. I remember I froze. It was like I pressed a pause key in my head, and for a moment I couldn't hear a sound, just stared at that one photo moment of my surroundings. At first, it was like a moment that I had already experienced in the past. Only not quite, as I wasn't able to identify the moment, and perhaps the better explanation would be that this was the moment comparable to a computer reboot - like the computer in my brain rebooted itself in a microsecond, and the image that appeared first in the memory was the same one from the moment before rebooting, or the brain's CPU froze for a couple of moments while all senses were still on, and this image appeared in multiple memory locations and was therefore more intense than others. However, this is how I felt after that night, and ever since then I have had more similar déjà vu experiences, but this first one was, for some reason, more memorable than all the others.

I can't be sure, of course, but whatever it is, it must be related to how the brain works, and it is either a brain feature or a bug. Scientifically speaking, we still don't have working knowledge of a human brain, and therefore it is hard to tell, but we could say with high accuracy that the human brain is not a digital computer. More plausibly, it functions in some sort of analog form where all data stored in brain neurons are not comparable to memory chips we are using today. Perhaps they operate like quantum qubits, where one qubit could have unlimited states instead of just two, like modern memory circuits have today. That way the same arrays of qubits could be used to store different images, and to pull out the one you need, quantum computers only need to set the patterns and form the image out of current states of qubits. However, I am not saying that the human brain is a quantum computer, only that as soon as we learn more about its functionality, we will have more skills to explain the "déjà vu" phenomenon as well.

However, what we can do even without a scientific background is to use something else, and that's the "Occam's razor" principle. In short, it advises us not to use complex explanations, and instead the right one is usually the simplest one. So if we try that and reject all complex ones, like multiple universes or dimensions, quantum entanglements, and invisible forces able to connect two human brains in the subconscious realm, what is left is a simple explanation, and that one would be that the "déjà vu" moment is really the image acquired in our brain that really resembles some other image we experienced before. Only in that particular moment does the brain fail to recognize it. It is a really great explanation. Just think how much data we acquired in our lives. We watched hundreds of movies during our lifespan, watched television daily, traveled, encountered different people and situations, and participated in various events. So, in short, there must be tons of data in our heads, and there is no wonder we are unable to see the difference or to recognize them all instantly. Remember these moments when some smell reminds us of some event, even those distant in our childhood? This is the same with images and moments. Sometimes some similar settings or moments remind us of something, but we are simply unable to resolve what.

By recognizing the fact that I am not really that great a presenter within my blog stories, I decided to ask for the help of one of the great thinkers today. The following video is how Michio Kaku explains déjà vu" in Big Think's series:

However, science works by proving theorems. So, there is nothing wrong if we post a couple of theories for future validation. But we have to be careful here, as every theory must be built on solid ground; otherwise, it is only a speculation at best. I guess it is valid to claim that the human brain is a sort of quantum computer, but it is hard to prove it at this point in time, as we still don't have working quantum computers other than experimental ones. If, in the future, we develop and industrialize quantum-based systems and servers, then we might have the tool to examine the brain in such a fashion and then confirm or reject the "brain quantum computer" theory. On the other end, speaking of a solid ground base for establishing theories in addition to quantum computers, to me one thing is clear, and you probably heard it in the media in the form of a short phrase: "We all are made of stars". It is complete truth, and I mean this literally: all atoms you, I, and Michio Kaku are made of originate from exploding stars, and such violent explosions are a great source of quantum entangled particles. We still don't have full knowledge of quantum entanglement, but it is proved that entangled particles share the same properties on both short and long distances, maybe even in time. So, based on current research, and if entangled particles are able to survive long lives without breaking entanglement, it is not far from common sense that two individuals can share two such particles that connect them in some way. Plausible? It is still years too early to tell, but it is certainly something worthwhile exploring. It would explain a lot. Especially the famous so-called 6th sense and even those common situations in everyone's life when you, during walks, all of a sudden start thinking about a friend of yours without any reason, and then a couple of blocks later you meet him in a flash. It happened to me a couple of times. I love science, and I am sure this will not be my last post about yet unexplained phenomena.

Every now and again I stumble upon titles and articles about the greatness of scientific thought and why we must never stop pursuing it. I also have a short personal story to add additional value to the topic: when I was a boy, I remember I asked my father why both the sky and the sea are blue. He didn't think twice and said that the sky is blue because we can't see how high it is, and the sea is also blue because we can't see how deep it is. He pointed to my head and said, "One day you will learn that eyes are not the ultimate tool of perception. Your brain is."

A couple of years later, I stumbled upon one great article about optics, Isaac Newton, and prisms in my favorite magazine and learned all about visible light and its wavelengths. Ever since then, I know exactly why the sky and sea are blue.

References and story follow-ups:

http://en.wikipedia.org/wiki/Déjà_vu
http://www.youtube.com/watch?v=Ks_UHmaZcSg
http://en.wikipedia.org/wiki/Occam's_razor
http://skepdic.com/occam.html
http://en.wikipedia.org/wiki/Qubit
http://en.wikipedia.org/wiki/Quantum_mind
http://www.healthkicker.com/754397472/whats-up-with-deja-vu/