An overview of the String Theory – the proposed Theory of Everything. Read on for an interesting take on this theory of everything.
“Christ!” yelled Bugs Funny, munching on a flaming orange carrot, “what do they expect me to do next, stretch myself thinner into a string and wind myself into a loop?”
I could understand Bugs’ trepidation – the studio had really been giving him a hard time for the past few months. While stretching himself thinner was not a complete impossibility, what with him being a composition of penwork, I really had my doubts if the results would look too good. Aloud, though, I said, “It wouldn’t really be a bad idea, Bugs.”
He looked at me in horror. “Whaddya mean? As it is these artists are stretching and twisting and dressing and undressing me mosta the time, doc, no need to provide them with encouragement”, he said, a note of consternation in his voice.
“Ah well, it would’ve been good publicity for you, though. You could be the first Grand Unified Rabbit in the world.”
“What was that again?” the note of alarm was distinct now. Suppressing a smile, I opened my mouth to offer him solace, but Chaffy Duck butted in first, “He’s punning on the Grand Unified Theory, you moron!”
Bugs looked positively hurt that there was something which Chaffy Duck knew but he did not.
“Ain’t got the joke yet, Doc. What’s so grand about this grand whatchamacallit anyway?”
I sighed. It seemed like there would be another of those long drawn theory classes -knowing Bugs, I was sure that I was better off explaining than not. So, with another sigh and a shrug, I set myself down to the difficult task.
“You are aware of Gravity, right, Bugs?”
“Yes, of course. It’s that thing which throws you off a cliff when the director wants, right?”
This was going to be even more difficult than I thought.
“Well, yes, sort of. You see, long back Sir Isaac Newton proposed that all bodies attract one another, all bodies with the exception of you two,” I looked sternly at the duo trying to feign rapt attention, “and a few centuries later, Albert Einstein came up with a more developed general theory of relativity which sought to explain gravitation in terms of space-time curvature and not as a permanent, omnipresent force. However, Einstein soon realized that while his theory held good most of the time, it still could not explain everything. There was no equation that could explain both force and particles in the same breath. You see, the mathematics of quantum mechanics broke down all known particles into two classes: bosons and fermions. Bosons are particles that transmit forces. Many bosons can occupy the same state at the same time. However, in case of fermions, only one fermion can occupy a given state at a given time, as fermions are the particles that make up matter. That can explain why we normal beings cannot walk through walls, why even cartoon characters like you have to bore through solid objects – fermions (which form matter) cannot share the same space the way bosons (which form forces) can.” I paused for a breath here, and Chaffy quipped.
“Ah gotta ask my director to bosonate me in the next feature”.
I gave him a glare and continued; “Now in our environment, there are four observed forces, namely the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. A separate theory exists to explain each force. However, what the scientists wanted was to create a unified theory, something which could encompass all these theories together to form one, single theory that explains everything. But to understand force fully, one also needs to understand the particle completely because one gives the other its identity; that is; one provides a reference frame for the other to be understood. For example, if Chaffy duck had not been there, Bugs Funny would not be so popular. Chaffy, then, becomes the reference frame for the audience.”
“I ain’t no frame or anythin’ doc” Chaffy squawked, insulted.
“My apologies. It could easily be the other way round; I was just stating an example about reference frames,” I said, not wanting a fight breaking out midway through the subject. To be entirely truthful, I was gradually warming up to the topic, “I’ll try a different example. Suppose you are pushing a wall, it means that you are exerting a force on some matter. But what if you are pushing, but the wall simply isn’t there? Would the push have any meaning then? Would you be able to understand the nature of the force that you are exerting in the absence of something of a particle nature? No. And that is why the scientists set out to understand the particle first. The first question that came to their minds was – “Which is the fundamental particle?” And to look for the answer, they did something that many found ridiculous – they started smashing the known particles against each other at very high speeds in the hope that some new particle might emerge from the collision. And they succeeded, to an extent. For example, when they smashed two protons together, they came up with anti-proton – a particle with characteristics exactly opposite to protons. Similarly, colliding electron yielded positrons. However, most of these new particles could only exist within the collision device – the Supercolliders as they are called. So our scientists gradually narrowed down to twelve fundamental particles which compose everything known to us. These were called ‘matter particles’. They also identified some ‘force particles’, that is, particles that carry force from one point to another.”
“These are the Bosons and Fermions’, right?” Queried Bugs Funny, very much excited now.
“Right. Now with a general understanding of the particle, the scientists also came to understand the nature of ‘force’. Now they set out to decipher the all important code – the code of everything. They named the elusive theory GUT – acronym for Grand Unified Theory. Some scientists prefer the name TOE, though – SHORT FOR Theory Of Everything. You see, with the development in the understanding of force and particles, there are only two basic theories that are used to describe everything, the first being Einstein’s theory of relativity describing gravity as a result of space-time curvature and the second being Quantum Mechanics, which describes force in terms of little packages. What remained was to unify these two theories and propose one fundamental theory. And that is where the scientists came up with the theory of Strings.”
“I can get your pun now, Doc. But how come Chaffy Duck knew about all this before me?” asked Bugs Funny.
“That is because Chaffy was busy brushing up on his physics while you were running around hogging the spotlight,” I said sternly. ” To continue, the String theory postulates that the entire known universe is composed of infinite strings of Planck length – which is about 10-33 centimeters – existing in two states, of open loops and closed loops. It is the vibration of these strings that gives rise to the different forms of force and matter that we see around us.”
“Didn’t getya Doc – how can strings make up matter or force?” Bugs Funny was curious.
“Okay, look at it this way. Imagine you are playing on a harp. Each string on the harp plays a different note depending on the length of the string. Similarly, different vibrating patterns of the cosmological strings give rise to different forms of force and matter. Take a closed loop string, for instance. The space-time curvature of the closed loop string’s co-ordinates is determined by the vibrations of the loop, and it is the space-time curvature within the loop which determines the behavior of the loop. It is quite paradoxical if you try to understand it within the four-dimensional model where there are three dimensions of space and one dimension of time. But you must remember that our strings are essentially one dimensional structures functioning in within 10-plus dimensions. Classical physics cannot comprehend so many dimensions, and that is where String theory fits in beautifully.”
“Ten dimensions?” Yelled Chaffy, “How’s that possible?”
I smiled. Yes, it is tough to comprehend, “You see, initially the universe was considered to be made up of three dimensions – length, breadth and height. However, along came Einstein and he put forth a claim that there existed another dimension, that of time. Now, to compute the gravitational force exerted by one object on another, it has been seen that the gravitational force varies as the inverse square of the distance between the two bodies. But what is distance? It is a 3 dimensional concept of length, breadth and height. Therefore, we can say that gravitational force varies in proportion to d-2 where d is the distance. But we can also write this as..,” I scribbled on the newspaper “..d(-3+1) , thereby incorporating the figure 3 for the three dimensions. Now, while solving the complex mathematical equations for the string theory, our scientists realized that the theory would be feasible, that is, the mathematical results would hold good for what is observed, where the exponent was more than 10. That is how we came to realize the possibility of more than four dimensions.” I set the pen down and continued, “In fact, there were as many as five different string theories initially, and it had been assumed that only one of these would finally be able to stand out as the Grand Unified Theory. However, it was later observed that each of these theories can be merged with the others to give rise to the superstring theory,” I paused, “The biggest problem with the superstring theory is that of evidence. While the theory sounds good, the infinitesimally small size of the string makes it impossible to test the same. The second problem lies in the number of dimensions. While the theory holds true with ten or more dimensions at work, it becomes difficult to manage the theory with the only four dimensions known to us. Several modifications have been proposed to the theory to make it work in four dimensions, the primary one being the Kaluza Klein Compactification which proposes to curl the extra dimensions into smaller spatial dimensions.”
“So you mean the theory is yet not established?” asked Bugs.
“If by established you mean recognized then yes, it definitely is recognized as an entirely new branch of scientific thinking. More and more scientists and mathematicians are jumping on the string wagon everyday, trying to work out the glitches in the theory. But if you are asking whether the theory has been tested and found true at all levels, then no, the theory is not established. While at planck energy the theory has been found to hold good, it is beyond our scientific knowledge at this point of time as to how the theory might behave at lower energy states. There is also a lack of observational evidence to support the theory, as I mentioned earlier. Further, the theory can, at best, only explain what happened after creation, but before creation…”
I raised my hands in the air,
“…God only knows.”