Introduction
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. String theory describes how these strings propagate through space and interact with each other. ... Thus string theory is a theory of quantum gravity.
What Is String Theory?
According to String Theory, every matter is a one-dimensional vibrating string at the smallest scale. Well, visualizing a one dimension object is beyond us. But physicists create such abstract objects using complex and advanced forms of mathematics. In any case, how can our solid world exist as vibrating strings? Are we saying that hard diamonds are nothing but small vibrating strings packed together? According to String Theory, this is indeed the case.
For humans, imagining anything beyond normal 3-D, is thorny. Every object that we see, however small, is still a 3-D object. Even a very thin sheet of paper is a 3-D object, although we normally treat this as 2-D for all practical purposes. Though we claim. that a sheet of paper has length and breadth but no thickness, this is not the case. Likewise, we treat a straight line drawn on a graph as 1-D, although in real life we have not seen anything like a 1-D object. But objects of 1-D, 2-D and more than 3-D, are represented in math quite easily.
Understanding String Theory With An Example!
Let's use an example to help us visualize a 1-D object. Assume that you are looking at a 10-metre-long PVC water pipe from a distance of over 50 metres. From such a distance, the water pipe looks like a plain two-dimensional sheet with only breadth and length. Its curviness or depth is completely absent unless you observe it from a closer distance. The effect of this curviness is so small that we feel the pipe is a plain strip of PVC material and not a 3-D pipe anymore. Thus, viewing this object from some distance makes it lose one dimension out of the three. If you now walk still away from the pipe, you will soon see the pipe as a thin and long string. It now loses its second dimension of breadth as well, so all you see of the water pipe is its long and thin one dimensional length. Of course, this is due to a visual trick. The pipe always remains as a 3-D object.
String Theory says that the basic constituent of all matter is nothing but a one-dimensional vibrating string that is extremely small. According to this theory, these vibrating strings are as small as Planck's length which is 1.616199 x 105 metres. As said before, this is an unimaginably small size. If you treat Planck's length as equal to the size of a tree, then the size of the atom is that of the universe. This is the scale at which String Theory works. At this scale, even electrons and protons are quite huge!
How Strings Vibrates?
Depending upon how these one-dimensional strings vibrate, and in what pattern and orientation they vibrate, they generate particles like quarks, electrons, photons and other elementary particles of mass. Please recall that quarks, electrons (leptons), and photons (bosons), are elementary particles and that three quarks make up one proton or one neutron each. So these vibrating strings produce or create these elementary particles which, in turn, constitute large fundamental particles such as protons and neutrons in an atom.
Essentially, strings are the sources of every matter and energy that we see in the universe. So matter in its smallest scale (Planck's length) is made of huge number of strings. Depending upon the vibrating pattern of these strings, they produce or impart mass to matter and energy particles. Of course, this is the basic concept. The working model and associated math are formidable to even to scientists. The string theory is a complex theory and a product of several teams of scientists working both in isolation and together, formulating different versions of the basic concept. Later, all these versions of the string theory were clubbed together to arrive at one final version that now plays a key role in defining and modeling our world.
How String Theory Describes Our Universe?
Many theoretical physicists believe that String Theory is the only viable theory that truly describes our universe. Although it is making waves in the scientific world, it has not been tested practically. Probing our universe at Planck's length is one of the biggest challenges in science. The main argument in favour of String Theory is that it is a coherent framework which accounts for all the fundamental interactions between matter and energy in nature. The CERN lab in Geneva, is the best bet for String Theory to be proved right due to the nature of high energy particle research being carried out there.
Another aspect of String Theory is that the 1-D vibrating strings need space-time to have 10 dimensions, which means six extra dimensions than the usual four dimensions of space-time. String Theory provides a profound way to describe ultramicroscopic properties of our universe. Let's not get misled by assuming that these vibrating strings are pretty much like the string of a sitar. The strings of a sitar are made up of ordinary molecules and atoms and their harmonic nature is very much understood through the simple laws of classical mechanics. On the contrary, according to String Theory strings are one-dimensional mathematical objects that create matter and force particles such as quarks, electrons and photons. Unlike our sitar strings that exist in the ordinary 3-D world, the strings of String Theory exist in 10 dimensions (three spatial, one time and six extremely small curled-up).
Although String Theory has not been not been proved yet, scientists claim that the math employed to develop the model is flawless, and so we will one day have a proof of their existence in the lab. This theory is so advanced in its concepts that one needs to have mastery in the mathematics employed in String Theory and this is difficult even for experts in the field. The mathematical concepts, tool equations of String Theory are so complex that only a handful of scientists and scholars can really appreciate its significance.
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