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Showing posts with the label science

Camera Obscura

Perhaps it's a little weird for me to begin an article with a glimpse of a romantic movie, but I can't think of a cooler way to start today's topic. When I came up with the idea to write about "Camera Obscura", the first thought that came to my mind was a movie from 1997 called "Addicted to Love". Of all the movies in this genre, only a few are at the top of my mind, and this one, directed by Griffin Dunne with Matthew Broderick and Meg Ryan in lead roles, is definitely the best one I remember. In short, Sam, an astronomer who, in an attempt to win back his girlfriend, turns his astronomical tools into specific spy equipment and, by using his dark-chambered pinhole camera, manages to observe what is happening in the building across the street in real time. What he used to achieve this is a principle behind Camera Obscura—a method to project the light through a small hole and create an image on the opposite wall inside a dark room, tent, or box. Something first observed and described by Mozi, a Chinese philosopher, around 400 years before Christ.


AstroMedia 'The Sun projector' cardboard kit

To better understand what Camera Obscura really is, think of an eye—a small, almost spherical chamber where light enters via the cornea and through a small pupil, with the iris controlling how much light enters the eye. Light then passes through a lens, which can change its shape to focus the image. The image is projected through a transparent, gel-like substance to the back of the eye (retina and macula), which contains light-sensitive cells. The light travels in straight lines from its source, and because of this, the image is formed flipped and upside down. However, the brain receives the image via the optic nerve and interprets the scene correctly.

Just like in the movie and inside the eye, we could also create our own camera obscura, which in Latin means "dark chamber." Imagine a large room completely darkened by, for example, placing cardboard sheets over the windows with a small, shaped pinhole in the middle of the cardboard. The light from the outside will enter and paint a great image on the opposite wall of the objects from the exterior. Upside down and flipped, but that could be fixed by utilizing a couple of mirrors. Check below in references the tutorial made by PetaPixel*, an online publication covering the wonderful world of photography, or many other DIY videos from YouTube. There was also a camera obscura exhibit made by Robyn Stacey**, an Australian photographer and visual artist, that turned the Australian city of Brisbane on its head in stunning photographs.


Convert your room into a giant Camera Obscura by PetaPixel*

Today, as a continuation of the small astronomy thread on MPJ, I had my hands on a second AstroMedia kit (of three), and this one was made with the camera obscura principle for observing the Sun, its sunspots, planetary transits, and eclipses. Despite its size, it was surprisingly quick and easy to put it together, or more likely, I am becoming much more experienced with paper gluing. :-) Surely, compared to the previously assembled Galilean telescope replica, it was easier to paste more non-round parts than before with the telescope's multiple tubes. Nevertheless, the Sun projector surprised me with its rather large size.

However, the kit is not an ordinary pinhole camera. Instead of a simple aperture of the Camera Obscura, the solar projector has a lens and two convex mirrors to choose from that work together like a Galilean telescope from the previous post. It is designed to provide higher magnification, and a plane mirror redirects the image to a comfortable viewing position. The best of all, it has a cardboard-made Dobsonian base and can be adjusted to any height between 0° and 90°. Furthermore, on both sides, there are quarter circles with degree scales, which determine the angle between the position of the sun and the horizon, which helps in calculating the height of the sun. With additional apertures, it is possible to reduce the opening and amount of light that enters the box. Smaller apertures can make sharper images. It's a surprisingly comprehensive astronomical tool.


Phases in assembling the Sun projector

To be honest, I was a bit skeptical that all the parts were glued perfectly and aligned for the light to be beaming exactly from the objective lens through the convex mirror to the plane mirror and toward the white screen, but the "First Light", as the astronomers like to call the time of the first observation with brand-new equipment, showed the Sun disc amazingly clear and focused. Now I have to wait for the next eclipse to test it with, which will be in March 2025. Or for the next Mercury transit nine years from now. Unfortunately, the transit of Venus will not happen again in this century. In the meantime, I will definitely play a little more with it and test all its features, including observation of landscapes, as in the summer there is plenty of light, so stay tuned for more information about all it can do.

Unrelated to this project, it reminded me that observing the sun could be very interesting and enjoyable. Once, when I was watching the Sun through the reflecting telescope with a solar filter, a plane transited the Sun disk at the same moment of my observation of one of the previous Mercury transits, and it was so intense, to say the least. Imagine watching Mercury slowly pass through the sun's disk when suddenly the black shadow of an airplane passes the disk in less than a second. I was stunned for a moment, trying to comprehend what exactly happened. I would probably still be puzzled by the event if the airplane hadn't left a contrail behind it, which stayed for a while in the field of view along with small Mercury and a couple of sunspots.


Details from the Sun Projector's "First Light"

Amazingly, Camera Obscura could be dating even back to the past, way to the prehistoric settlements. There are theories that prehistoric tribe people witnessed the effect through tiny holes in their tents or in screens of animal hide, which might have inspired them to start with cave paintings. It was not away from logic that they would intentionally make the pinholes in order to monitor the exterior for potential dangers from within their shelters.

Anyhow, it was fun building the kit as well as writing about it. Nature is definitely full of wonders, even with something so simple to test, build, and understand, like it is with monitoring light behavior within Camera Obscura. By using the same principle, it is possible to make a small projector that uses a light from a smartphone to project it on the wall, and even the additional mirror is not required if the smartphone is positioned upside down in the first place. We played once with that as well, and the result is in the refs below.

Galilean Telescope (AstroMedia cardboard kit #1)
https://www.mpj.one/2023/07/galilean-telescope.html

What Jupiter and Mercury Have in Common?
https://www.mpj.one/2019/11/what-jupiter-and-mercury-have-in-common.html

Transit of Mercury
https://www.youtube.com/watch?v=e2yuXbUdj6o

Shoebox Projector
https://www.youtube.com/watch?v=WAsvUbysEk8

Ref:
 

Galilean Telescope

The knowledge and manufacture of lenses were known since the time of the old Greeks (the word optics came from the Greek word ὀπτικά, which means appearance) and later in the old ages with Egyptian scholar Alhazen, who made important contributions to the study of optics in general. In Europe, the lenses arrived around the 13th century and immediately triggered the invention of the first eyeglasses. However, one important discovery had to wait three centuries later in order to set off a wave of new discoveries in the field of astronomy. The invention was made by Hans Lippershey, the spectacle maker from the Dutch city of Middelburg in the Netherlands, who in October 1608 tried to apply for a patent for a tool he described as an aid capable of "seeing faraway things as though nearby". It consisted of convex and concave lenses in a tube capable of magnifying objects three or four times. For strange reasons, the patent was rejected, but the new instrument immediately attracted attention. Now known as a spyglass, the invention ushered in a new era in astronomy and was the foundation of today's refracting telescopes.


Cardboard replica of the original telescope made by Galileo

Only half a year later, in the early summer, Galileo Galilei at the University of Padua near Venice started to build his first telescope based on the one Hans' made. He managed to design and build telescopes with increasingly higher magnifying power for his own use as well as for presents to his patrons. Galileo was a skilled instrument maker, and his telescopes were known for their high quality. Just like the initial spyglass from the Netherlands, his first telescope was basically a tube containing two lenses, but he managed to enhance the power that magnified objects approximately nine times with his first designs.

Even though Galileo perfected the manufacturing of lenses and telescopes—in later years he managed to produce over a hundred telescopes, some of them with magnifications as high as 33—only two have survived and can be seen in the Museum Galileo (Museo di Storia della Scienza) in Florence. One of the two, especially designed for Cosimo II de' Medici, Grand Duke of Tuscany, with gold-embossed leather, probably had (with initial lenses from the end of 1609) magnification power of around 20. The limiting factor of these early refractors, especially those with higher magnification, was their small field of view, but still, it allowed Galileo to see that the Milky Way is just a multitude of millions of stars and that the Moon's surface was not smooth and perfect but rough, with mountains and craters whose shadows changed with the position of the Sun. He saw the phases of Venus throughout the year and the most interesting fact that planet Jupiter was accompanied by four tiny satellites that moved around it with distinctive proof that not everything in the heavens revolves around the Earth.


Phases in assembling Galileo's historical telescope

This particular, gold-embossed leather telescope from the Florence museum was the model for the AstroMedia cardboard replica kit I got my hands on last weekend. It was advertised as "with this historically accurate cardboard replica, you can experience firsthand the great research achievements of Galileo, which he achieved despite the optical performance of this telescope, which is modest by today's standards". All I could say after two days of carefully pasting pieces of paper one after the other was that I couldn't agree more, especially at the last moment when I pointed it to the one-kilometer-away sign of the neighboring shopping center and clearly read what it said. I can only imagine where Galileo pointed his first telescope and what his initial reaction was.

While Galileo did not invent the telescope in the first place, his contribution toward their use in astronomy and science earned him two phrase coins: Galilean telescopes, which now represent a popular name for a refraction telescope type, and Galilean moons, now referring to the first four of Jupiter's natural satellites.


Jupiter's moons as seen through modest reflecting telescope compared to the view
from a small refracting spyglass similar in size to Galileo's original telescope

Unfortunately, I cannot make any astronomy photos with this replica; after all, it is made of cardboard, and fixing it on the moving sky is a mission impossible, not to mention its extremely small field of view, which is perhaps less than a centimeter in apparent terms, which would provide only troubles for focusing the camera through it. For these reasons, I decided to embed a photo of Jupiter's moons as seen with a modest reflecting telescope (the one you can see in the background of the first image above). Below you can find a link to the YouTube video of the entire event we created a couple of years ago when Jupiter was close to Earth. In the upper right corner of the photo, I also included a small view of how Galileo might have seen Jupiter and its four large moons. It is what can be seen with a decent refracting spyglass or powerful binoculars, which, in terms of magnification power, stand at the level of Galileo's scopes.

Camera Obscura (AstroMedia cardboard kit #2)
https://www.mpj.one/2023/07/camera-obscura.html

Jupiter Moons (zviktor22):
https://youtu.be/VTEsXEx-tnE

Ref:
https://astromedia.de/Das-Historische-Galileo-Teleskop
https://catalogue.museogalileo.it/index.html
 

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 the Urlich'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 the 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's and Jonas' child, who is in the show 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 of 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 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:

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

Insights Discovery

It's amazing how different people react to the same thing. Consider the famous question, "Is the glass half empty or half full?" What do you see inside such glass when you spot it on the table? The water or the air? This is, of course, not a school-grade sort of question. Actually, there is no right or wrong answer here. There's no definite reason to consider anyone thinking that the glass is half full to be overly optimistic or those who see the emptiness of the glass to be unreasonably realistic. It is just a point of view and nothing more. But it tells a bit about your character, or how Carl Jung, a well-known Swiss psychiatrist and psychoanalyst, defined it—your personality type.

The point of inquiries like this one is simply in the fact that if we ask ourselves enough questions, they would have the potential to unveil our personality type fully, or to a high degree of accuracy. However, we would need to be careful in both selecting the questions and defining all resulting personality types. There are numerous personality tests within psychology, and of those based on Carl Jung's study, the most comprehensive is the Myers-Briggs Type Indicator, which assigns you a value from four categories: introversion or extraversion, sensing or intuition, thinking or feeling, and judging or perceiving. One letter from each category is producing a four-letter test result. For example, if your test is resulting in a dominance of introversion combined with intuition while you are basically a thinking person with perceiving feat, you would be assigned an "INTP" personality type.


Perhaps most of the psychology in relation to personality types is based on Jung's "Analytical Psychology", the phrase he coined in 1912 when he published "Psychology of the Unconscious", his breakthrough study, which firstly relates to his split-up with Sigmund Freud after six years of collaborating in the field. In this book, he establishes for the first time that his new theory focused on the collective unconscious instead of Freud's conception of libido and the importance of sexual development. When he first read it, Freud muttered the word "heresy" and felt that Jung had "lost his way" from that point on. Perhaps, just like with the 'glass half filled or half empty', this dispute between the two extraordinary men from the history of psychology has no definite winner or loser. They might both be right, depending on the point of view. After all, the human mind is driven by a still mysterious engine we keep trying to fully understand.

However, what's interesting in regards to the Freud-Jung dispute is what Jung said some years after the split-up. According to Jung, the main difference between him and Freud was their personality types being introvert and extravert, respectively. Their attitude types were pretty much opposite, as the first type was persuaded by the voice of their inner self while the second found their interest inexorably drawn to external things. In his book 'Psychological Types', published in 1921, he said that "since we all swerve rather more towards one side or the other, we naturally tend to understand everything in terms of our own type".


But, if we get back to the personality test, the most obvious question is: what would its application be? Other than in medical/psychiatric practice, I mean. Of course, we all know ourselves well, so there's no point of some test telling us what we really are. We already know that. If you have been friends with somebody for a long time, surely there is no need for any test to tell you the obvious about what you already learned about your friend from the experience. Clearly, and maybe the only use of such a test would be to learn about the personality of someone whom you don't really know well. However, the test, by its nature, is extremely personal, and it naturally raises a wave of privacy issues that are in most countries protected by the law, especially after previous decades of the expansion of the internet.

Keeping in mind everything we know so far, what's left and where one such test could be more than useful is, no doubt, all kinds of business environments. The offices are, by definition, filled with lots of colleagues, and the advent of knowing everyone's personality type would benefit communication between people and enhance productivity significantly. Providing, of course, that employers and employees are fine with sharing their personality test results with each other.


Finally, at the end, we come to the titled personality test that was created exclusively as a business application. Based on Dr. Yolanda Jacobi's interpretation of Carl Jung's theory of psychological type, along with other theories from psychology, 'Insights Discovery' is a simple and accessible four-color model designed to help us better understand ourselves and others. If you check the above picture, the basic colors are divided between introversion/extraversion (vertically) and thinking/feeling (horizontally). The test itself is a 25-frame questionnaire of 100 word pairs, which, when completed, produces the Insights Discovery Personal Profile. Of course, no person is entirely described by one of the colors alone. After all, we are all a mix of different traits that we display differently based on different occasions, environments, moods, etc. Hence, Insight Discovery offers a total of eight personality types, which are shown in the center circle with four more types, which represent a blend of two colors.

Please find more details in the references below, as I won't go deeper into the science behind 'Insights Discovery' than this. However, if you decide to take the test, you will get a result printed in detail explaining your personality type on more than 20 pages where you can find your key strengths but also potential weaknesses along with healthy tips for communication between types for both you and the others. What you also will get is a nice little colored Lego-like brick, which represents your colors. If assembled right, it shows your exact place on the Insights Discovery wheel, and it can do it for both your conscious and less conscious positions.

This little one below is mine.

 

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 are 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 similar 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 for 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
 

Is Infinity Real?

Sooner or later, computation hardware and artificial intelligence algorithms will inevitably reach the point of enough sophistication that the creation of a simulation of enormous proportions, for example, the size of the entire universe, will be effortless. So to speak. These god-like engineers of such future simulation will indeed face a decision point regarding which degree of limitation to create for their simulated entities or artificial intelligence units in order for them to never reach the point of finding the proof that their world is in fact nothing more than just a series of electrical or optical currents of one inconceivably powerful futuristic computer.

If created right, there's no doubt that the inner world of all those hypothetical units would seem to be as real to them as our own very reality is to us. So, considering the state of obvious, the question arises by itself: if our own reality is such a simulation and we are nothing but AI units within some alien quantum computer, what exactly is the limitation?


To me, it always has been infinity. My own limited mind always struggled with understanding what it really meant. Aristotle, who buzzed his head with infinity quite a lot, concluded that infinity is only potential in nature. We can always add a number to any number to the point of infinity or divide something into infinite parts, but in reality, he thought that it was impossible to exceed every definite magnitude for the simple reason that if it were possible, there would be something bigger than the heavens or something smaller than the atoms (Greek origin: άτομο, which means without volume and uncuttable).

Today we still can't find the proof of bigger or smaller volumes than we can see or understand. If we look up toward the heavens, we are pretty sure that we cannot see beyond the Big Bang or 14 billion light years in all directions due to the limitation of light speed. The same goes with understanding the smaller volumes of microcosm for which we think the current boundary is around the scale of 10e-12 Picometres due to the quantum limitation of observable micro space without disturbance by the observer.


All things considered, as proposed by mathematics, infinity might be just the other word for really, really big, or extremely small, or very old, or too far away. In every way, simply put, infinity might be just beyond our reach. Perhaps if we are really living in the simulation, this is our limitation, and we are pretty much designed in the realm of simulated physics to never reach it and to never learn what is behind the horizon. Ironically, the ultimate truth could be that there was nothing there. It might be where simulation ends and where alien software developers' backdoor is located. Their own reality could be entirely and unimaginably different.

But what if we are not living in a simulation? What if all the laws of physics were not invented by an ingenious developer and were instead real, perfectly natural, and not artificial in origin? Would we have a volume larger than heavens or smaller than quarks and strings? Or just maybe these two extremes are somehow connected and twisted in a loop with no need for infinity at all? Perhaps, ultimately, the size could be irrelevant and not a factor in all cosmic equations.
 
1 +  = ?

http://sten.astronomycafe.net/is-infinity-real/
https://en.wikipedia.org/wiki/Infinity
 

What Jupiter and Mercury Have in Common?

Before we jump to premature conclusions with easy answers such as 'nothing at all' or 'at least they are both orbiting the Sun', perhaps we could do some quick research, just in case... With Jupiter's equatorial radius almost thirty times bigger than the same property on Mercury, the obvious composition difference between one gas giant and a small rocky planet and all the other major differences in mass, density, temperature, orbital inclination, and orbit period, and with almost everything we could compare the two, it is very hard to find the slightest similarity. Not to say that Jupiter in its arsenal is in possession of moons equal to or even bigger in size than the smallest planet of our solar system.


However, within the past couple of seasons, what they had in common was the fact that they were under the spotlight of all of us who, from time to time, enjoy gazing at the sky with our naked eyes or through modest telescopes with a strong feeling of being the witnesses of our own solar system at work. It all started at the end of last year with a rare Jupiter-Mercury conjunction when two planets came close to each other to the size of two moon-diameters. It was easily observed without any optical aids just after the sunset on December 21, 2018.



Even better, the show was on June 12, 2019. On that day, the giant planet was closest to Earth during the celestial event known as Jupiter’s opposition. At its closest point, it came to within 641 million km from Earth. We took the chance to point the telescope and observe the mighty planet and its four largest Galilean moons: IO, EUROPA, GANYMEDE, and CALLISTO. If you watch the video, you'll find the entire story of the event and more facts about the history of the most famous moons, along with short footage from the Sky-Watcher and references in the video's description.



Culmination in our amateur astronomy happened a couple of days ago on November 11, 2019, with the celestial transit of Mercury over the face of the Sun. It was the last transit of the small planet for a while, and the next time it is going to 'eclipse' the mother star again will be in 2032! It was hard to take the photo of the event since it was fuzzy and cloudy with the sunset approaching rapidly, but we made it at last, and it was worth all the efforts.

Stay tuned for more celestial events in the future and maybe some more stories and photos from the active heavens, along with our first long-exposure astrophotographs from outside the solar system.
 

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