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String Theory: The Search for a Unified Theory

Describes the fundamental aspects of String Theory and its role in modern science.

Tigist Diriba

on 6 April 2011

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Transcript of String Theory: The Search for a Unified Theory

By: Tigist Diriba String Theory and the Quest to Find a Unified Theory of Everything The Progressive Uncovering of the Forces of Nature Newton in the 1700s with Gravity.
Maxwell with electromagnetism.
Einstein in 1910s with general relativity and e = mc2.
1920s revolution with quantum mechanics which totally turned everyone’s view of the cosmos upside down.
Revealed the strong nuclear force and the weak nuclear force along with the fact that down at the atomic level it’s impossible to fully predict if one event is going to happen, one can only calculate the probability of it. The Purpose of String Theory The whole purpose of String Theory is to unite all of the natural forces that at the moment only explain their limited environments. This is what a Grand Unified Theory is meant to do.
Before String theory was proposed it was believed that everything in the universe was made of tiny points of 0 dimensional energy, but this idea was speculated by many because it led to a dead end. With 1 dimensional “strings” it’s possible to explain a whole lot more on the laws of nature. Einstein Einstein viewed the cosmos as being composed of a fabric of space and time. He wanted to explain gravity through this because relativity describes gravity as warps in the space time fabric.
The Journey of Unification After providing the world with the theory of relativity which created a united picture of the universe, Einstein began looking to merge Gravity with Electromagnetism and procure a Unified Theory of the Universe.

Einstein was an idealist who viewed the universe as symmetrical and predictable, and fueled by the fact that Gravity and Electromagnetism are similar forces, he chose to follow this path at unification. Einstein’s realization After much time spent in research, Einstein realized that despite their similarities, Gravity and Electromagnetism were profoundly different. For one thing, Electromagnetism is one duodecillion (10^ 39) times stronger than Gravity. That’s a 1 with 39 trailing zeros.
Quantum Mechanics Quantum Mechanics was revealed in the 1920s by a group of scientists (led by Niels Bohr). Quantum Mechanics began to uncover the inner workings of the atom, which previously was thought to have been the smallest particle in nature.

With the new discovery came new and game changing questions. At the subatomic level, science couldn’t explain what was occurring with the laws of gravity or electromagnetism. This led to the discovery of two new forces, the strong nuclear force (which keeps the nucleus of atoms together) and the weak nuclear force (which allows the transformation of neutrons to protons). With Quantum Mechanics, it was deemed that at the subatomic level, there weren’t always definite rules that had to be followed. One could only calculate the probability of something happening. This changed everything for Einstein because it forced him to disregard the notion that everything was in a perfect and predictable order.
Another problem that scientist were facing was the discrepancy of the so called fundamental forces of nature. This was realized when the sciences had to be regarded into two distinct senses. Gravity governed the celestial objects whereas the other forces of nature governed the microscopic and atomic levels of the universe.
String Theory The fundamental idea is that everything at the most basic level is composed of strings of energy which are varied through the frequencies at which they vibrate.
How Strings Caused a Revolution String Theory as it became more complex began to uncover a possibile world of 11 dimensions and potential time travel. String Theory with its contradiction to all of our bliefs was now causing a revolution. Worm Holes As Einstein believed, space and time can be distorted. This distortion could have enabling worm holes to come into being. Worm holes act as a kind of passage way between different parts of the universe. With worm holes, space and time travel is possible.

He believed that although it’s possible for space and time to warp, it’s impossible to rip the fabric of space and time meaning that it would be impossible to generate a worm hole.

String Theory now dictates that it is possible to rip the fabric of space and time because Strings have the amazing ability to mend it. This means that however difficult it may be, worm holes can be generated. Strings and Their Dimensional Space Now it is believed that with String Theory, there are 11 dimensions in which the Strings move in.

The 7 more dimensions, excluding the three dimensions of space and the 1 dimension of time, are invisible to us.

These dimensions are believed to be necessary for strings to move like they are predicted to.

With this idea, it is also insinuated that strings have the capability to expand into something like a membrane which can potentially grow into an enormous size. How Did String Theory Begin No, it didn't actually start with someone asking the question, "I wonder if everything were made of tiny vibrating strings?" It actually began very unexpectedly.

In around 1968, two scientists (Gabrielle Veneziano and Mahiko Suzuki) began attempting to unearth the secrets of quantum mechanics and remove the confusion that scientists had on the four fundamental forces of nature.

Theses scientists astonishingly came across the Euler beta function which could describe the interactions of the strong nuclear force. When the function was used to give a picture of subatomic particles, it gave rise to strings. It was in this way that Strings were born. Membranes The implications that strings can expand into more than 4 dimensions is huge.

It means that there is a possibility that our universe is a small part of a much larger extra dimensional space.

We could simply be a small “slice” of the extra dimensional space and possibly be living next to
parallel universes. String Theory Tackling Gravity It’s believed that everything that we see in composed of strings that have closed ends, meaning that they are tied down onto the 3d membrane that makes up the space of our universe. Though to explain gravity, it was proposed that there exists Strings that are closed looped called Gravitons which are the cause of Gravity.

Since Gravitons are open looped, they can move freely between dimensions. Also, the reason why gravity is so much weaker than the other fundamental forces of nature is that, Gravitons are dilute because of their ability to move freely between dimensions. Is it a Science or a Philosophy? Although it was widely believed that there could be no way to figure out whether or not String Theory was the Grand Unified Theory, today there are many laboratories around the world working with the power of particle accelerators to uncover the String.

The idea is that, although one could never see the String, it would be possible to feel the effects that Strings would have in certain experiments. Fermilab and CERN These two have been using their particle accelerators to begin to uncover the secrets of the atom.

By colliding two Hydrogen nucleis, they are making it possible to take a look into the subatomic particles and reveal the truth about String Theory.

This is being gone about by attempting to measure the absence of Gravitons when they are released from the Hydrogen nucleus (keep in mind that Gravitons are Strings with open ends and would float away freely).

Another aim of these labs is to find sparticles which would verify the theory of supersymmetry. THE END
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