In physics, working of the universe is explained by two theories-
Einsteins ‘theory of relativity’ dealing with the working of large bodies.
Quantum mechanics dealing with the working of quantum particles.
These two frameworks had proven to be sufficient to explain most of the observed features of the universe, one at the micro level and other at the macro level.
Larger bodies like stars, planets, galaxies are made up of small subatomic particles or quantum particles, by default the laws working behind large bodies should also be applicable to their subatomic particles. But the reality works opposite, the laws working behind larger bodies fails when applied at the quantum level.
There should be a single theory which should explain the system of the universe as a whole and should be applicable at both micro and macro levels. This means that a new theory was needed to bridge the gap between the two. If such a theory is developed, it should be regarded as the parent theory of the two.
Let’s have a look at this new theory known as the string theory. Originally developed in the 1970s by Leonard Susskind (Father of The String Theory).
The String Theory
In physics, string theory is in which the point-like particles of particle physics having zero-dimension are replaced by one-dimensional objects called strings.
Four fundamental forces of the universe are-
Gravitational Force, Electromagnetic Force, Strong Force and Weak Force
These forces work in different ways to sustain the universe. Each one is understood as the dynamics of a field. The gravitational force is modelled as a continuous classical field. The other three are each modelled as discrete quantum fields, and exhibit a measurable unit or elementary particle.
According to scientists, strings have many factors and follows the fundamental theory of physics. Most notably, a theory of strings that evolve and interact according to the rules of quantum mechanics will automatically describe quantum gravity. Which can give birth to the Einstein’s dream i.e. Unified Field Theory (UFT). This means that string theory can bridge the gap between the two existing theories.
In addition to the problem of developing a consistent theory of quantum gravity, there are many other fundamental problems in the physics of atomic nuclei, black holes, and the early universe. String theory is a theoretical framework that attempts to address these questions and many others.
In string theory, there is only one kind of string, it can vibrate in different ways. In this way, all of the different elementary particles may be viewed as vibrating strings.
String theory depicts strings of energy that vibrate, but the strings are so tiny that you never perceive the vibrations directly, only their consequences. Nature of vibration can be better understood by the type of wave called a standing wave.
Types of Vibrating Strings | Quantum Gravity
The strings may be Open (forming a segment with two endpoints) or Closed (forming a loop like a circle) called Type I strings and may have other special properties. Interactions between open strings always result in closed strings. One of the vibration modes of a closed string can be identified as the graviton.
In string theory, one of the vibrational states of the string gives rise to the graviton, a quantum mechanical particle that carries gravitational force. Thus, string theory provides a better answer to the quantum gravity.
Studies of string theory have also yielded a number of results on the nature of black holes, gravitational interaction and extra-dimensions.
11 Dimensions of String Theory
According to Einstein’s theory of space-time, we live in the world of 4 dimensions. Space containing three dimensions (x,y,z) and fourth dimension is time.
Consider a point, it has no length, width or height so, it has no dimension.
A line has length but no width or height so, it has one dimension.
Square has length and width but no height so, it has two dimensions.
Cube has length, width and height so, it has three dimensions.
String theory states that there is a possibility of higher dimensions. There can be the existence of 7 more dimensions in the universe. As per the theory, these different dimensions together or individually can hold their universe like our universe which is made up of four dimensions. However, no higher dimension is yet found.
It is almost impossible for us to explore other dimensions as they are too small to get detected. Therefore, it becomes impossible for us to jump into the other dimensions.
Everything Vibrates in the Universe
According to string theory, all particles are actually tiny vibrating strings and each type of vibration manifests a different particle. The different particles are like the different notes that can be played by plucking a violin string.
In fact, the matter itself is seen as the manifestation of standing waves of strings. Different vibrational modes give rise to different particles! Bosons are force carrier particles. Fermions are usually associated with matter.
Whether it’s a heavy particle that is part of an atom or a massless particle that carries light, is due to its resonant pattern, or how it vibrates.