String Theory - String theory is defined by Merriam-Webster...

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Unformatted text preview: String theory is defined by Merriam-Webster as, ?A physical theory in which one-dimensional loops travel through space and also merge and lyse as time elapses. This is in contrast to ordinary quantum field theory, which predicts point particles that emit and absorb each other. String theory is a candidate for a Theory of Everything.? String theory would solve the long fight between Einstein?s theory of relativity and Quantum Physics. String theory proclaims that everything in our universe, from stars and suns to apples and atoms, is made up of incredibly small particles called strings. Strings are so small, that if an atom were the size of our solar system, a string would be the size of a tree. There are six different string theories. Each is classified by a type; Bosonic, IIA, HO, HE? Each has its own way of explaining what strings are, and how the make up our regular life objects. But each theory uses the basic structure illustrated by the picture at right. Each object in the universe that we know of, from gum to galaxies is made up of atoms. In turn, each atom is made up of protons and neutrons, which have electrons circling their nucleus. For as long as we have known about them, scientists have pictured atoms, and the quarks that make them, as balls. String theory proclaims that there are tiny vibrating strings instead of these balls. It says that each string vibrates at different wavelengths, and that is what makes up our universe. Strings are easily and often compared to the strings on a musical instrument, such as a guitar. On a guitar, each string makes a certain note, depending on the speed it vibrates at. The shorter the string, the faster it vibrates, producing a higher note. Strings do almost the exact same thing; depending on which theory you look at. In some string theories, strings are defined as one-dimensional non-looping objects, but in most, they are shown as one-dimensional loops. The reason why string theory is so revolutionary is because it unifies the two major theories that describe the universe; Einstein?s theory of relativity, which uses the most familiar of the four forces, gravity, and quantum mechanics, which are responsible for the other three: strong nuclear force, weak nuclear force, and electromagnetism. Strong nuclear force is the force that binds together the protons and neutrons in an atomic nucleus. In other words, it holds together everything we know in the universe. Out of all of the fundamental forces, strong nuclear force is the strongest. Electromagnetism is the next strongest; it is 100 times weaker than the strong nuclear force. It is responsible for all light and all energy in the universe. It also produces magnetic attraction, such as the north and south poles of a planet. You could also say that it is responsible for the reactions between charged particles. After electromagnetism comes weak nuclear force. Weak nuclear force is responsible for the decay in radioactivity. It is 1,000,000 times weaker than string nuclear force. Lastly comes gravity. Gravity is responsible for interactions which occur because of mass between particles, and between both large and small masses of matter. It extends over infinite distances, but is mainly in visible distances. Gravity is the weakest of the forces, as it is 1039 times weaker than the strong nuclear force. When all four of these forces act as string theory describes, every event in the universe, from an explosion to the birth of a planet, are just these four forces interacting with matter. String theory does have doubters, though. Many scientists believe that string theorists shouldn?t even be called physicists, because there is no way to do experiments to prove or disprove that it is true. In the mid 1970s, quantum physicists made extreme breakthroughs in the science of combining strong nuclear force, weak nuclear force and electromagnetism. Although this was a huge step forward in finding the ultimate theory, it only described the world of the very small, and did not include the most familiar of these forces, gravity. During this time, string theory was losing supporters. It had only provided us with the theories of massless particles, and tachyons, particles that move faster than light. Until, one day, a scientist who had been rearranging and adjusting the equation thought, ?maybe this is gravity we?re talking about?? This idea would force string theorists to think of strings as immensely small particles. And that the equation they had been dealing with was really the thing that the relative theory needed: the graviton, which is supposed to be able to transmit gravity at the quantum level. The scientists, published this amazing new discovery, but the board of experts who reviewed everything that came in, didn?t like it. But this didn?t stop the handful of string theorists still left. They worked for years, and eventually, it paid off. Once all of the anomalies were worked out of string theory, it took a leap into the field of science. String theory has become one of the most promising theories proposed. But what if it proves to be wrong? Well, first off, string theory is unique, because there is no way to prove it wrong. To some, that means that there is no way to prove it right either. So is this a theory that really truly describes what goes on anywhere at anytime? No one can know, but it is a promising idea.
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This note was uploaded on 06/10/2008 for the course PHYS 420 taught by Professor Maynard,juliande during the Fall '08 term at Pennsylvania State University, University Park.

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