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
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
