(Assignment #10) TED Review: Brian Greene on String Theory

     As a student who dreams to be a physicist, I always have desired to learn about the string theory, which is one of the most pivotal theories in modern physics that has a key to unify all the laws of physics and solve the enigma of the universe. But since the theory is too abstract and esoteric, I have not had a chance to study it. However, through the TED video, I could learn the theory quite elaborately in an easy way because the man clearly explained the theory with lots of examples, metaphors, and graphic images.

To understand the string theory, one should comprehend the background of the development of the theory. First, in 1907, Einstein suggested an unprecedented and novel theory that gravity occurs because the space warps and curbs due to the presence of the matter. Inspired by the idea, a German mathematician Kaluza tried to apply the same logic to electromagnetic force. He adopted the fourth dimension of space, and demonstrated electromagnetic force by warp and curve of the hypothetical dimension. The derived equation corresponded to the orthodox ideas about the force, and the hypothesis seemed to be authentic.  

<Einstein's theory on gravity - space warps and curbs!>

However, the hypothesis arose two relevant questions. The first question: Can an additional dimension exist, even though it is not recognized? The question was answered by Oskar Klein. According to him, a tiny, curled-up dimension might not be able to be seen. As we cannot recognize the width of a thin wire from far away, we cannot feel the tiny dimension because the dimension is too tiny. Therefore, an additional dimension might exist if it is extremely tiny and curled-up.

The second question: Does the real universe follow the theory? The answer is ‘no’. Unfortunately, several researches and experiments done in ‘40s and ‘50s conspicuously proved that the world does not follow the theory. And here string theory comes out.

String theory demonstrates all phenomena by stating that tiny vibrating strings of energy compose the whole universe. As the strings of musical instruments vacillate and make euphony, the strings of energy vacillate and make matter. As the pitch of a sound depends on the length of the string, the type of a particle depends on the vibration frequency of the string. Even though the theory seems to be eccentric, the theory definitely provides us a path to the unification of all physical phenomena, considering that every matter and forces consist of the strings of energy.

<Vibrating string of energy>

Meanwhile, according to the calculation derived by the string theory, the space should include ten dimensions. The ten tiny, curled-up dimensions intertwine and coalesce themselves and form a complicated structure. Therefore, if we observe the world in the tiniest scale, the space would be composed of the incoherent intertwinement of dimensions.

<Intertwinement of tiny, curled-up dimensions>

The theory has a profound significance; it can explain the mystery among the twenty numbers of the universe. The universe can be described by twenty physical quantities such as the mass of an electron, the gravitational constant, and the electromagnetic constant. The numbers are so exhaustively balanced that the smallest change in the numbers might lead to the collapse of the universe, and scientists have been zealous to find out how the balance is accomplished. If the string theory develops furthermore and scientists become able to calculate the vibrational patterns of the strings and the geometry of the ten dimensions, they would eventually discover the order of the nature that balances the twenty values.

Experimental results should advocate the theory to make the theory resolute. Recently CERN is preparing an experiment that would prove string theory. In the particle accelerator, particles will undergo numerous head-on collisions. Then, if the theory is correct, some of the debris of the collisions would be relegated from the tangible dimensions and enter other dimensions in a form of a particle called ‘graviton’. Therefore, if the energy in our dimensions is decreased after the collisions, the existence of the additional dimensions would be proven.  

<CERN particle accelerator>

The video introduced string theory to me in an entertaining and comprehensible way. Contrary to the abstract documents about the theory which I could not even attempt to read, the explanations in the video were relatively much easier to understand. The graphic animations greatly helped me making images in my head and understanding them.

String theory definitely seems to be marvelous as it leads to the unification of all laws of nature and explanation to the minute balance of the twenty significant physical values. I want to learn more deeply about string theory. I would challenge reading the documents and books and watch other lectures about the theory. If I become a physicist, I would be glad to participate in completing the theory. Now I am fanatic to string theory!