Are We All NPCs?

Let me answer with what I think right away. To me, this is not one of those yes-or-no questions because it's impossible to tell. Simply put, the theory behind the question is most likely unprovable. Not from the inside anyway. 'Simulation Hypothesis' and the phrase 'non-playable characters' are relatively new concepts, born not that long ago, when digital computing came to be fast enough to produce graphically demanding multiplayer games sophisticated enough to hint at this question and the probability that we might also be inside one of those simulations. And to dispute the question about the nature of reality is quite useless, because everything that surrounds us, no matter how strange we think it is, can also be real and not part of the code. Even if our reality were simulated, its origin would be extremely difficult, if not impossible, to prove. By design, nothing inside the simulation could be able to see the lines of the code, only the outcome of its work. In order to say that we are all NPCs, something extraordinary has to happen. Something unexpected, like a bug in the code. A glitch that would clearly break the laws of physics.

On the other end, in the future, near or far, the engine behind simulated characters in games would be even more sophisticated in a way that all characters would be able to easily pass Turing's test. To act just like you and me. The AI behind them would be so advanced that they would be equal to the human players. Or much better. So to speak, one game in particular has already achieved this goal. The Chess. When asked about chess engines, Magnus Carlsen, the current world champion, said exactly this: "I find it much more interesting to play humans. And also, of course, now that they have become so strong in a game like that, I wouldn't stand a chance". I love chess, but I have to admit I disagree with Magnus—playing against computer bots became more and more indistinguishable from playing real people. In the most popular chess.com engine online, I solely play against computer personalities behind the Komodo and Stockfish engines, and I have enjoyed them for years. But I agree that playing against humans is much more fun. For now. Let's revive this talk again in a decade or two... Or three... When chess bots develop more of their personalities. More non-chess features. A sense of humor, maybe.

In any case, the main problem with simulation theory is that it lacks a definition of reality itself. What it really is. Is this what we are living in? If it is simulated, where is it simulated from? If we skip all the philosophical views so far solely based on Nick Bostrom's book 'Are You Living in a Computer Simulation?' and stick to the physics realm only, I think that simulation of any reality or anything at all requires two prerequisite conditions to start with. One is that there is a high probability that the system performing the simulation should be distinct from its simulation, and the second is a large complexity behind it, something that Jonathan Bartlett from the Blyth Institute explained with "The problem with that [simulation in general] is that it always takes more stuff to simulate something than the thing you’re simulating".

Additionally, we are kind of looking at the simulation hypothesis today through the gaming lens, in which simulated reality must have 'real' players from the original coder's reality. But what if our reality, if being simulated, is not a multiplayer game? What if it is a zero-player game? Or not a game at all? In that case, we all could be NPCs, and there would be no real players. Because original and simulated reality could be two completely incompatible actualities. What if simulated reality is not a computer program at all? What if it is something else entirely?

I know I post a lot of questions here, but bear with me. If we follow the logic of a more complex, upper reality, which is distinct enough from its simulated creation, what would I think of first? For me, it's shadows in Plato's 'Allegory of the Cave'. In his famous work, Plato describes a group of people who are chained to the cave, facing a blank wall. All they saw were shadows projected on the wall from objects passing in front of a fire behind them. The shadows are the prisoners' entire reality, while the objects before the fire represent the true forms of the items that they can only perceive through reason. Plato goes further elaborating on his mind experiment, but for our topic, let's focus on the shadows themselves. They are just two-dimensional images of something coming from the upper third dimension. They are distinct from the original objects and certainly less complex and the product of a comprehensive setup.

Well, the final question arises by itself. Is it possible to cast three-dimensional shadows of four-dimensional objects? Just like a square represents a cube from the third dimension, the cube could be just a shadow of a tesseract's fourth-dimensional counterpart. The casting in this scenario would not be as simple as in Plato's story, nor would the shadows be what we mean by the term, but it's definitely something worth giving a second thought. One hypothetical four-dimensional reality would be an ideal source of three-dimensional simulations, and there's even a scientific theory that 'casts' light in the right direction. It's called the 'holographic principle'.

The origin of the theory lies in black holes, and the best is to quote my fictional self from the 'Revelation of Life', a hard science short story I wrote a couple of years ago: "If Hawking was right, any black hole, no matter how massive, would evaporate over time. When that happens, all the information swallowed inside would be lost. The problem is that quantum dynamics is clear about it—nothing, especially information, can ever be lost." The solution to this paradox is that the information belonging to the objects swallowed by the black hole should not be part of the three-dimensional reality in the first place. The holographic principle states that "the description of a volume of space can be thought of as encoded on a boundary to the region", or the dimensional boundary surrounding the entire universe, while our familiar space-time continuum might be just a (holographic) projection of the entities and events located outside.

Finally, and to get back to the original titled question, in this reflection we indeed could be all NPCs in a hypothetical simulation originated from the upper dimension. Just like in a famous zero-player game invented by John Horton Conway, a mathematician from Princeton University, a simulated three-dimensional world can only be a setup, created with an initial state and left to evolve on its own. Just like we culture bacterial colonies in a Petri dish. Or it can be a more complex setup with added life forms driven by conscious artificial entities or even by 'real' people from the upper dimension. For the question of why such a simulation would be created in the first place, there is no good answer. The reality of a fourth (or fifth, sixth, etc.) dimension would be something we wouldn't be able to fathom right away. Or at all. Nevertheless, I thought about one simple reason and embedded it in the 'Revelation of Life', but if you are eager to read it, please watch 'Game of Life' first, a short film that precedes it.

Game of Life (Simulation story, prequel)
https://www.mpj.one/2016/08/game-of-life.html

Revelation of Life (Simulation story, a hard science fiction)
https://www.mpj.one/2020/10/revelation-of-life-part-one.html

Refs:
https://builtin.com/hardware/simulation-theory
https://mindmatters.ai/2021/01/jonathan-bartlett-on-why-we-do-not-live-in-a-simulated-universe/
https://chesspulse.com/is-magnus-carlsen-better-than-a-computer-2/
https://www.chess.com/terms/chess-engine
https://medium.com/@jacksimmonds89/are-you-an-npc-this-may-disturb-you
https://en.wikipedia.org/wiki/Simulation_hypothesis
https://en.wikipedia.org/wiki/Holographic_principle

Image ref:
https://www.imdb.com/title/tt0139809/

Time Travel and Superposition in Dark

I was no more than four years old when our car got stuck on a snowy hill decades ago. Everyone but me went outside to push to get us out of the frozen road. More people gathered from other cars to help each other, and soon everyone was engaged in a small rescue operation. That certainly didn't mean I didn't help—as well as others pushing the car from the outside, I did the same from the inside. From the back seat, I put my hands on the front and pushed hard. In my defense, deep down I knew that what I was doing was kind of weird and useless. At the time, I just didn't know why. I was just ashamed sitting alone and doing nothing. Well, like they say, with age comes wisdom, and now I know that what I did was physically impossible, just like in the case of Baron Münchhausen—when he got himself and his horse he was sitting on out of a swamp by pulling his own hair upwards. And just like in an old expression about an absurd and impossible thing one can do—if I were to pull the bootstraps on my shoes up, lift myself into the air, and jump over the fence.

In science fiction, the word bootstrap is also used to portray the impossible task in all the paradoxes that are always hard to understand. Within time travel, the bootstrap paradox is a theoretical paradox that occurs when an object, information, or human is sent back in time and becomes trapped in the infinite cause-effect loop in which it no longer has a detectable point of origin. For a simple example, if I somehow send a copy of this very blog post to my younger self before I write it in the first place, the origin of the text becomes utterly unknown. It exists in the time loop, and I become just somebody who typed it in. Yet, the text will still have my own style of writing and my own thoughts written down and not somebody else's. Hopefully, you will not find this case implicitly weird, because weird in this blog post is yet to come.

I have been aware of the existence of Netflix's 'Dark' for a long time now, but due to its scientific background and complexity, I knew it required continuous binge time to watch it, and last weekend I finally decided the time was just right, and I swallowed all three seasons in just three days. Like no other TV show, it was solely based on time travel and quantum superposition, and... in a word, it was outstanding. With lots of characters to follow through both space and time, it did require full concentration, but thankfully, due to the fantastic direction, script, and performances of all involved, it was more than understandable and enjoyable, to say the least. It is impossible to continue this without spoilers, so if you are eager to watch it first, this is the point of this blog post to stop reading, and I advise it strongly.

Anyhow, Dark's premise is all about bootstrap paradoxes. There are multiple plotlines in the show heavily embedded in time loops, just like my example of this blog post traveling to the past. If that was weird, imagine what this kind of paradox, involving time travel of real people and their intertwined stories, could do to your sanity only as an observer. On top of that, season one passed with very few or no special effects, and there was no reason for that either. In Dark, all the post-time-travel effects are already embedded in the future, or the present, from where they traveled back in time. For example, Helge already had all visible face scars that were consequences of Ulrich's time travel. Also, the stories about the murdered woman on the bottom of the lake were already socially spread even before Katharina was murdered in her own time travel.

Even though Mikkel's time travel was the prime story behind Dark, where he ended up being a father to Jonas, the main protagonist, for me the strangest and most ingenious bootstrap paradox is Charlotte, who was born in the future, traveled to the past as a baby, and became a mother to Elisabeth, who in her own future became a mother to Charlotte herself. The endless loop between them lies in the fact that they are both mother and daughter to each other. And even this is not the weirdest bootstrap compared to the entire Nielsen family. Martha and Jonas' child, who is in the show and the strangest character of them all, in his own time travel became a father to Tronte, who was Martha's own grandfather. This practically means that Martha's son was his own great-great-grandfather. In the aftermath, most of the members of the Nielsen family are practically the result of a direct or inherited bootstrap paradox and have to thank their existence to time travel itself.

To be honest, I was so perturbed and unsettled with all the relationships by the end of season two that I was not sure how they would come out of this at all. There were so many open loops with no indications how it could go any further. At that point, I thought that this show would go down the drain very quickly, or they must come up with something even more out of the ordinary to continue the story. And then, at the very end, in the last episode, came another Martha, who stood by the dead Martha and answered Jonas' question about where she came from exactly with "Die Frage ist nicht aus welcher Zeit, sondern aus welcher Welt". Well, I am not fluent in German at all, but I know a word or two, and in this case I knew very much the difference between Zeit and Welt. In the outcome, even before the subtitle showed up, I was left staring at the screen with my mouth wide open.

The final season introduced even more time travelers, both new and doppelgangers, but more importantly, the story started to unveil now with the introduction of the cause and effect of the quantum superposition mirrored in the macro world(s) and character's actions. In the quantum world, superposition means particles can exist in different states and even multiple places at the same time. The weirdness comes if we try to observe the process. At that instant, superposition breaks into just one outcome of their many. Just like with the double-slit experiment of light behavior* or in binary superposition with Schrödinger's cat in the show explained by H.G. Tannhaus in one of the episodes.

The difference between the micro and macro worlds, with time travel involved, was that in the macro realm it was now 'possible' to act differently in the same time loop and in one pass to choose one outcome and in the other a different one. That allowed for the same superposition collapse, but in two time loops to create two different Jonas' and two different Marthas and to even further complicate the intertwining situations now with three worlds involved. In the ingeniously written ending of the show, as I expected, time travel loops were impossible to untangle, and the only outcome was, again with time travel interfering, to save one world at the expense of the other two and, by doing so, to prohibit any time travel in the original world.

The ending of two worlds disappearing was just perfect and beautiful, and the very last scene explains which of all the characters survive existence and which ones were only products of either direct or inherited bootstraps and therefore not possible to exist in the final world.

* Reality of Double-Slit Experiment
https://www.mpj.one/2022/11/reality-of-double-slit-experiment.html

Strange world of physics and time travel at MPJ:
https://www.mpj.one/search/label/physics
https://www.mpj.one/search/label/timetravel

Refs:

https://www.astronomytrek.com/the-bootstrap-paradox-explained/

Dark refs:

https://www.thisisbarry.com/film/netflix-dark-the-bootstrap-paradox/

https://invisibledragon.home.blog/2020/06/28/dark-and-the-bootstrap-paradox/

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

Serendipity vs Zemblanity

Do you gamble? I don't. Not because it is not fun, nor because it is one of the famous five sins. It is simple for me. I never win. I tried a couple of times with lottery tickets, and I never won a dime. Not to mention that I am terrible at predicting sports results or winning any kind of gambling event. I remember once I watched a Eurovision contest and had a strong feeling that the Austrian band would win big time. Their performance was great, and the song was pretty good. I even typed one of those SMS messages to support them. And yet, they scored exactly zero points! Were they bad? No. Check the video within the YouTube references below. They were pretty good. Only sometimes, luck doesn't come with quality... It chooses by some strange criteria, as it seems, I will never understand.

When I was in high school, I thought I was smart enough to build some system by analyzing previous results in the national lottery and to win at least the second prize, which would be enough for me to buy the super home computer of the time. Nope. It was a complete failure and a waste of my time and efforts. It goes so far that sometimes it could be completely disturbing and cruel for my inner emotional personality. Let me give you one example: we have a projector clock, a small gadget in our bedroom that shows time and temperature on the wall. A couple of seconds is the time that's written on the wall, and the other couple of seconds is the temperature. My luck is going that much down, so when I want to see the time, the wall is beautifully decorated with temperature. You guess, when I want to see the temperature, I always need to wait first for the annoying time to disappear from the wall before showing what I want to see. Ok, ok, it is not always like that, but it is also not a 50-50 chance, as everybody would expect. I checked. More than twice. It's irritating. So don't call me Lucky, because it is not my middle name. However, I strongly believe in universe balance in everything, so my inner luckiness balance is not an exception either. My middle name could be Serendipity - not really in Fleming's kind of way, but I definitely have some "scientific" or "intelligent" or "accidentally on purpose" kind of luck, or whatever way serendipity could be described better.

I tried to find a better description of the word on the net, and after all, the best explanation was given by Julius H. Comroe, Jr.; he described serendipity as "to look for a needle in a haystack and get out of it with the farmer's daughter". Ok, ok, I am not that lucky as well, but this is it. Let me explain my usual experience when I get stuck with some programming problem and I can't find the solution. This is not that kind of blockage when I have to learn new stuff to continue. These are those events when I have to investigate the problem on the net for a couple of hours and find nothing useful. I mean nothing at all. Before, in the past, I was desperate, and I always ended up rewriting the complete code from the beginning, but now I simply know that when I am not finding anything on the topic of something as big as the internet, it usually means there is no problem at all! What it means is that I am simply forgetting to include some semicolon or experiencing some other small and syntax-related error, or I am simply too tired to see the solution staring at me invisibly. Luckily for me, serendipity saved me so many work hours, and I always describe this as "I found the solution by not finding it".

There are many well-known serendipities in the past, and probably the most famous is the story of how Alexander Fleming discovered penicillin and how this accidental discovery is continuously saving lives, not to mention resulting in research in antibiotics and a continuous fight with bacterial diseases up to date. Here is the complete story from the NOVA science article "Accidental Discoveries"*: "While researching the flu in the summer of 1928, Dr. Fleming noticed that some mold had contaminated a flu culture in one of his petri dishes. Instead of throwing out the ruined dish, he decided to examine the moldy sample more closely. Fleming had reaped the benefits of taking time to scrutinize contaminated samples before. In 1922, Fleming had accidentally shed one of his own tears into a bacteria sample and noticed that the spot where the tear had fallen was free of the bacteria that grew all around it. This discovery piqued his curiosity. After conducting some tests, he concluded that tears contain an antibiotic-like enzyme that could stave off minor bacterial growth. Six years later, the mold Fleming observed in his petri dish reminded him of this first experience with a contaminated sample. The area surrounding the mold growing in the dish was clear, which told Fleming that the mold was lethal to the potent Staphylococcus bacteria in the dish. Later he noted, 'But for the previous experience, I would have thrown the plate away, as many bacteriologists have done before.' Instead, Fleming took the time to isolate the mold, eventually categorizing it as belonging to the genus Penicillium. After many tests, Fleming realized that he had discovered a non-toxic antibiotic substance capable of killing many of the bacteria that cause minor and severe infections in humans and other animals. His work, which has saved countless lives, won him a Nobel Prize in 1945."

Beautiful story, but due to my bad luck (awkwardly convenient to the topic), I hate to say that I am allergic to penicillin. Nevertheless, Fleming's story is the kind of serendipity I wanted to mention in this post. This is something that has driven me personally my whole life and what I identified as my friendly companion in my work and life. Compared to pure luck, for me, this is not something that you have to count on in your journey. Rather, it seems that this is the kind of luckiness you deserve somehow, simply by not giving up on what you are doing. In other words, if you are persistent enough in reaching some goal, little serendipity will smile at you when you least expect it. Sometimes I like to call it intelligent luck, a kind of luckiness that is given by some big amount of research—a reward of some kind, if the effort is truly genuine.

More than a century before Fleming, there was one more, I'd say even more "effective use of serendipity". It was in the late 18th century, in the time of the legendary "philosopher's stone"—a myth describing the existence of the mysterious substance capable of turning base metals into gold. Among all those alchemists of the time, the best known was Hennig Brand, who thought the mystical substance might be, well, urine. So he stockpiled it in enormous quantities, especially from beer drinkers, and started brewing, boiling, stewing, and experimenting with gallons of yellowish liquid. He didn't produce any gold, of course, but in the end, he did find a whitish substance in the sludge that glowed in the dark. What he discovered was the element phosphorus. The name, appropriately, starts with "p"**

While reading about serendipity on the net, I found something I didn't know—the word "zemblanity". It is completely opposite to serendipity—something like "unpleasant surprise" or "development of events in a non-happy or non-beneficial way". As the word is unfamiliar, the effect is not; sometimes I experience this one as well. When this happens, for me, it means that I am really doing something I shouldn't do in the first place. I wonder if the "universe balance" in humans like me is true when pure luckiness is rare and serendipity is not, then what is the counterweight for those lucky ones? Maybe they experience zemblanity often?

Yin can't make it without the Yang.

Original post: March 2012, Updates: December 2017, May 2018

Article quotes:
* http://www.pbs.org/wgbh/nova/body/accidental-discoveries.html
** https://www.npr.org/sections/health-shots/phosphorus-starts-with-pee

The Makemakes
https://youtu.be/duW-PsDbysg
http://www.themakemakes.com/

Refs:
http://www.sciencemuseum.org.uk/images/I061/10326668.aspx
http://en.wikipedia.org/wiki/Serendipity
http://news.bbc.co.uk/2/hi/technology/5018998.stm
http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1385402
http://www.barnesandnoble.com/w/accidental-genius
http://www.himalmag.com/component/content/article/464-serendipity-and-zemblanity.html
http://serendipitypatchwork.com.au/blog/2007/02/10/serendipity-zemblanity/
http://zemblanity3.blogspot.com/
http://www.biography.com/news/alexander-fleming-5-other-accidental-medical-discoveries

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

Fringe Dream of Virtual Particles

Last night I had a vividly strange science fiction dream. Like with most of my dreams, and dreams in general, I guess, it was hard to recall all the details in the morning, and this one was no exception, but in a nutshell, the scene started with me in some science lab, describing the idea of how to effectively make a tiny hole in the universe. It was pretty simple—I was using four Tesla coils, perfectly positioned in the corners of the large square with edges of about a couple of meters long and with two small, battery-sized metal plates positioned in the center of the square. The experiment was that at the precise moment, Tesla coils fired four filaments of thunder, reaching the center point exactly between two metal plates at the same time, initiating a process that in the end created a tiny breach in the universe that I was describing in the dream as a brane between dimensions and within the void between multiverses. Anyway, in the process, one plate goes from metallic through dark and eventually invisible, while the other started immediately to glow and emit light and other sorts of radiation.

I was explaining in my dream that the breach positioned one plate just outside of our universe while the other stood here. Most of the pairs of virtual particles that were popping between two plates all the time out of vacuum are torn apart by the invisible plate, making them real particles from that point and attracting one toward itself, while the second particle is always attracted by the other plate, creating radiation and the glow in the process. Very similar to the Hawking radiation emitting from the event horizon of the black hole. Even though those two plates were positioned very near to each other, after the Tesla coils did the job by breaching the universe, they stayed in different realms from that point, keeping a relatively close distance between them and finding new equilibrium even when the coils were shut down.

Our plate was then taken out of the square center, wrapped in the bigger case, and used as a battery that never drains. Or, to be precise, not until the invisible plate in the system that is always outside of our universe depletes itself by doing its job of separating the particles, but it was explained in the dream to be an extremely slow process that takes centuries, even if the battery is used to generate lots of power, like empowering entire city blocks.

I know, having a geeky or nerdy dream can be weird for most people, but it's not that we can choose what to dream, can we? It is surely a product of my daydreams, so to speak, and definitely an outcome from my daily interests in astrophysics by watching various documentaries and reading articles online. The novel-like storyline was definitely the consequence of all of my science fiction fascination in both movies and books, which I enjoy from time to time as well. In this very case, the background of the entire story from the last night and today's post is all about the most intriguing feature of the universe. The one that might change everything one day. Virtual particles. They are one of those scientific theories that has extraordinary potential for the future. If we find a way to capture and control them. Hopefully not by poking our universe with bolts of lightning. :-)

But seriously, and sci-fi aside, let's see why virtual particles are one of those quantum properties I think we still wait to understand fully. First of all, they are not really virtual per se; they differ from real particles only by their short existence in time. Aside from that, they can have some or even all properties of the real particles, including mass, but so far it is not really possible to observe virtual particles due to their short lives. However, in the subatomic world, virtual particles are often found in diagrams invented by Richard Feynman that revolutionized theoretical physics by their simplicity to explain what was really happening during the quantum events.

For example, take the Feynman diagram above. It shows how two electrons collide. The internal line is a virtual photon, which is in this case a representation of the excitation of the electromagnetic field caused by electrons and their interaction. We can observe both electrons, their velocities, and paths, but we are helpless to spot the virtual particle. In this very case, whether this virtual photon is really a particle, lasting only a tiny fraction of time during collision, which would give it the title of an actual mediator of the force, just like what its counterpart, the real photon, is, or it is used just as a calculation aid, it is not really certain, but in the end any particle, real or virtual, is only a representation of the excitations of the underlying quantum fields. However, even though they are called "virtual" because of their unobservability, and even though we can't see how they "look" and "act," in one experiment we are definitely able to observe what they do. Experiment proposed by Hendrick Casimir in 1948 and confirmed by Steven Lamoreaux in 1996. The experiment is probably responsible for my dream in the first place. The Casimir effect of the virtual particle-powered machine is just by using two metal plates positioned very near each other. But to understand the Casimir effect, we need to understand one simple thing. Timespace itself. I am not kidding. This is mandatory and a requirement for further reading. Easy. ;-)

Well, I am not pretending that I understand what really happens in the universe, but mainstream science of the current date says, and I am trying to paraphrase it, that all that is around us and within us and at any point in time is just one soup of various fields. Like the Higgs field I talked about once earlier on the blog. Or gravitational field. Or in this post's story and this particular case, electromagnetic field. Any field, by definition, is a region in space (and time?) that is affected by some force. At any point in the field. It also means that a field is a region in space that contains energy. Now, an electromagnetic field is not something that can occupy a certain part of space. It is literally everywhere. It is a fundamental field that is actually in the background of the entire universe and not just in places with matter. Everywhere. Even in the vacuum, where nothing tangible exists. Some places contain more energy than others, with a vacuum being a place with the electromagnetic field in its lowest energy state. Not zero. Now, keep with me; it gets interesting—let's compare this field with actual soup that is always boiling.

If you are looking at the surface of the boiling soup, you will see bubbles and fluid filaments all over the surface, but at some places they are heavier and more powerful, and at other places they are calmer and more peaceful, but always boiling and moving. If we were able to glimpse a closer look and magnify the surface to see it on an even smaller scale, we would see that the entire surface is in a chaotic state of constant wibbling, wabbling, wobbling, blooping, and bubbling*. The same is with electromagnetic fields. The stronger wabbles are what we identify as electromagnetic radiation that propagates forward (and in the case of our soup, outside the pot to the kitchen floor), while the tiny wibbles are just a short-lived emission of photons or failed radiation, if you will.

That tiny failed radiation is possible thanks to quantum mechanics that allows temporary violations of conservation of energy, so one smaller particle can become a pair of heavier particles, and in the case of a photon, it goes from changes of being a wave, a mediator particle with no mass, or a pair of heavier particles—a couple of electrons and positrons (or a pair of quarks and antiquarks with radiation of one gluon). What exactly it is and when it happens is dependent on the ongoing process and energy levels of the system, but in the case of the lowest energy state of vacuum, we know that heavier particles are popping all the time, and due to the uncertainty principle, those virtual particles always appear in pairs. They are borrowing the energy from the vacuum and immediately collide and annihilate themselves, repaying the energy in order not to violate the laws of thermodynamics. These streams of virtual particles "coming out of vacuum and diving back" are well-known quantum features known as quantum fluctuations of the electromagnetic field.

Now, those virtual particles popping out into short existence are coming pretty randomly—and in all possible wavelengths—which brings to "the surface" a vast amount of energy due to their short life, normally invisible to us. If we position two uncharged metal plates very near to each other (less than a micrometer), only those virtual particles whose wavelengths fit a whole number of times into the gap emerge between the plates, while outside, without limitations, all possible wavelengths are accounted for. The result is that energy density between the plates is way less than the energy density of the surrounding space, and immediately a tiny force appears and starts pulling the plates toward each other. This force is named the "Casimir force", and the entire system the "Casimir effect". On first glance, it doesn't look strange—the same effect can be made with two plates in water that, with small waves created by a sonic generator**, are pulling toward each other as well—but keep in mind that the actual Casimir experiment is performed in a vacuum with no single atom of matter between or outside the monitoring system, and the plates are uncharged. So the "only effort" we need to make is to put them very near to each other, and they will start moving. The force is tiny, though; for example, for the one-square-meter plates apart by just one micron, the force is 1.3 mN*** (the weight of 1 kg is about 10N). The force is stronger for bigger plates and with shorter distances in between.

However, one potential propulsion engine, built on the principles of the Casimir effect with even a tiny but constant push like this one, is comparable with ion engines that create thrust by accelerating ions with electricity. For example, in "Dawn", the spacecraft that recently arrived in the asteroid belt was propelled by three xenon-ion thrusters, each with a force of only 90 mN. Eventually, after more than 8 years of travel, it accumulated acceleration over the mission to more than 10 km/s (41,260 km/h), which is pretty fast for a tiny push (even though it used other means of acceleration like gravity boost while transiting Mars). It carried almost 400 kg of xenon for the ion thrust engine, but the potential Casimir engine of the future would need none of such a payload. Its propellant would be the very vacuum of spacetime and its pairs of virtual particles.

Of course, the real application would come with separating virtual particles like in my dream or what black holes seem to do**** on a daily basis. If there is a way to make virtual particles real, the millinewtons will instantly lose that 'milli' prefix and be equipped with one more powerful (perhaps 'kilo' or 'mega'), and that will be something extraordinary. Something that in science fiction has a cool acronym. ZPE. Zero Point Energy. Surely, we must find other means to deal with this than by creating tiny black holes to do the job for us, but thankfully, the quantum world is always full of surprises, and perhaps one day we will build a machine that is capable of taking the energy out of a vacuum safely and is small in size, relatively speaking. Perhaps another quantum effect will be helpful for this job, the one that uses interactions between hydrogen electrons and virtual particles called the Lamb shift. But that is a story for another time.

Image refs:
https://www.nasa.gov/mission_pages/dawn/main/index.html
http://www.livescience.com/50119-superconductors-physicists-gravity-particles.html
http://pics-about-space.com/black-hole-hawking-radiation-diagram?p=3

Refs:
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
* https://www.youtube.com/watch?v=Kn5PMa5xRq4
https://en.wikipedia.org/wiki/Zero-energy_universe
https://briankoberlein.com/2015/03/06/nothing-but-net/
** https://www.youtube.com/watch?v=PS8Lbq2VYIk
https://www.scientificamerican.com/article/are-virtual-particles-rea/
http://physics.stackexchange.com/questions/147096/are-virtual-particles-tool
***http://math.ucr.edu/home/baez/physics/Quantum/casimir.html
https://en.wikipedia.org/wiki/Virtual_particle
****https://en.wikipedia.org/wiki/Hawking_radiation

Gravis Gravity by Gravitons

Don't take this title too seriously. It's wrong on multiple levels. Grammatically and scientifically. Nonetheless, it fits perfectly for this post. As for grammar amiss, I used the Latin root word 'Gravis', which means heavy, and it is actually the perfect adjective for gravity as we perceive it here on Earth. As for the scientific issue, the rest of the title might be all wrong. If we glimpse into the features of the three main natural forces of the universe, it is obvious that they work in more or less the same fashion—they use carriers or elementary particles to mediate the force through the force field. The photon is one of them, and it carries electromagnetism, while strong and weak forces in the nucleus, respectively, are mediated by gluons and W/Z bosons, and they are all confirmed in experiments. Gravitons are supposed to be the same thing as gravitational force, but they are never found and confirmed either directly or consequently. Ever since Einstein, we have had second thoughts about whether or not gravity is acting as a 'normal' force at all or if it is something entirely different.

Think about this: you are located in the spacecraft far in space outside of the big, heavy planets and stars and truly experience microgravity. You start the engine, and your fancy spaceboat starts accelerating with about 10 m/s, and each second increases the speed with 10 m/s more. Actually, the right number is 9.806 m/s per second, which is the measurable 1 g force of the planet Earth. In our thought experiment, a spacecraft that works in a fashion that always uses constant acceleration and half the journey from, i.e., Earth to Mars, pushes with 1g, and the other half turns around and uses backthrust with the same 1 g, could not only provide a normal human environment inside the craft, but it would also be very fast and reach the red planet in just three days*. If you can't imagine how this would be working in real space travel, I will only state the name of one fictional spaceship from the sci-fi literature. Its name is Rocinante**, and it is one great piece of interplanetary Corvette from the amazing franchise "The Expanse".

Well, science fiction aside, the point here is that gravity and acceleration seem to be one thing. The obvious conclusion in this chain of thoughts is that Earth and Rocinante are both capable of creating gravity of one steady g. At least it looks the same from the observer's point of view. However, we know for sure that Earth is round and rotates, and no matter where you are standing, it will pull you toward its center without accelerating anything. It's just enormously big and does something to the very fabric of spacetime itself, which is actually pulling you by invoking some mechanism we don't understand yet. Perhaps by using gravitons—our friendly force carriers from the title? Actually, both particle and string theories predict gravitons as real things. In the former case, it is a massless boson with spin-2, while in one of the string theories, it is sort of a closed string with a low-energy vibrational state. I will not go into further scientific details in both theories, but it is evident that a massless particle or low-energy string is very hard to observe, as it either never or extremely rarely interacts with other particles on subatomic levels. Let's compare it with neutrinos for a moment—an elementary particle with no charge and the tiniest mass we can detect. Their large, super-awesome underground detectors, like the Super-Kamiokande Neutrino Detector in Japan, detect only a handful of neutrino interactions with regular matter over a long period of time. For example, when light from the Big Kaboom from supernova SN1987A reached the Earth, Kamiokande detected the sum of only 19 neutrinos from this super explosion. And to use Carl Sagan terminology, there were billions and billions of neutrinos only from that event. Detection of a single graviton, even if we consider some theories that suggest gravitons with non-zero mass, would be extremely hard.

Ever since Einstein's general theory of relativity, scientists have been struggling to find the best description for gravity. If we are looking at it as a fourth natural fundamental force, compared to the other three, it is the weakest by far; for example, gravity is about 36 orders of magnitude weaker than electromagnetic force, and it probably has a trivial influence on subatomic particles. However, it is cumulative and always attractive and therefore plays the major role in the macroscopic realm, making it possible for planets to orbit their stars, and it is behind the recently experimentally confirmed gravitational waves by the LIGO (Laser Interferometer Gravitational-Wave Observatory) experiment. Einstein himself first noticed the difference in behavior of four fundamental forces and spoke of gravity as not a 'normal' force per se but more as a fictitious (or apparent) force that is observed only as a consequence of the curvature of spacetime caused by the presence of large masses or energy throughout the universe. A very nice example of one apparent force is the Coriolis force, or Coriolis effect. It is observed as a force, but in reality it is just an apparent deflection of an object that is moving in the spherical system, such as Earth, that rotates. Deflection is caused by the fact that the rotating speed of the Earth is faster for a moving object located near the Equator than for one near the pole. In simple words, the system you are moving in is also in its own motion that must be included when you want to calculate the actual path of yours; otherwise, you will never reach your intended target. And in the universe, everything is in motion. Gravity could be just that—an apparent force that is caused by the interaction of large moving masses with the fabric of the universe itself that might be in its own motion as well. Or perhaps gravity could be the outcome of the interactions of mass with the potential energy of that fabric itself. In science fiction and also in the quantum science realm, this is known as zero-point energy, quantum vacuum zero-point energy, or simply vacuum energy. If I understand this correctly, by applying Heisenberg's uncertainty principle (we can only know the position or velocity of a moving particle, but never both), every quantum system to sustain this principle must have minimum non-zero energy. In the case of a vacuum, this is the minimum energy of all fields in the universe, including the necessary Higgs field needed to provide the existence of every mass everywhere in the cosmos in the first place.

In the conclusion of the scientific part of this post, I am hoping that whether the future will confirm gravitons and 'pronounce' gravity as a real fundamental force or we finally find how big masses influence the tiny quantum world of the universe's fundamental ingredients, in the end we will have our answers, which might bring more challenges and questions for future generations. Maybe even ways of mastering it by applying some ingeniously clever engineering of future gravity-related devices and tools. Of course, how exactly the world would be changed with full understanding of gravity and gravity-based appliances; perhaps the best vision is in the science fiction of the amazing futuristic thriller "Influx", written by Daniel Suarez.

I am always eagerly acquiring novels with gravity premises in the background if the plot teaser is interesting enough, so I bought 'Influx' a while ago and stored it in my Kindle's queue for future reading. I was a little busy with my work and reading a couple of other novels, but now I have this regret of why I didn't read it sooner. It was really amazing! Just exactly as comprehensive and entertaining as I was hoping for when I saw the book cover in the first place. The science behind the gravity mirror or deflector invention in the book is perfect and just in the realm of sci-fi plausibility I am always looking for. It was explained perfectly well in both the science behind the invention and also in the workflow of all engineering vehicles, armor, satellites, and other appliances that were built on it. If you add to the main 'gravity' twist all 'regular' sci-fi inventions such as AIs, robots, cold fusion, quantum computers, futuristic weapons, immortality, and other non-sci-fi thriller stuff, please believe me that my additional regret after reading this book was that it had only 500+ pages. I wouldn't mind if Daniel added more stories to it and created a sequel. I read somewhere that FOX is interested in the movie, and hopefully this will see the daylight in the end. It perfectly fits for a motion picture, not just because of the science and story but also because of the potential artistic and visual aspect of gravitational falls in all directions that was extraordinary.

Image refs:
https://www.artstation.com/artist/deningart
http://www.thethoughtarchitects.com/2014/04/14/detecting-neutrinos-neil-degrasse-tyson/
http://www.thedaemon.com/

In-text refs:
* http://www.johndcook.com/blog/2012/08/30/flying-to-mars-in-three-days/
** http://expanse.wikia.com/wiki/Rocinante

Refs:
https://en.wikipedia.org/wiki/Graviton
http://www.japantimes.co.jp/news/2012/01/08/national/science-health/japans-super-k
http://rationalwiki.org/wiki/Zero-point_energy
http://abyss.uoregon.edu/~js/glossary/coriolis_effect.html
https://www.youtube.com/watch?v=i2mec3vgeaI