In this article we will be learning about the elementary particles, Fundamental forces, string theory and its key concepts and a lot more. These are very popular topics among physicists. So its gonna be a long and interesting ride.
ELEMENTARY PARTICLES:
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| Standard Model |
To start understanding this theory let us first look into the composition of matter, we know normal matter is made of molecules which are made of atoms which are further made of protons, neutrons and electrons. Out of these three only the electron is an elementary particle while protons and neutrons are further made of smaller particles called quarks. These quarks and electrons are called elementary particles because they cannot be broken down further.
There are other elementary particles such as muon, tau and neutrinos, these are also called Leptons which consist of three neutrinos, an electron, muon and tau. There are also a total of six quarks, up, down, top, bottom, charm and strange quarks. Together quarks and leptons are called fermions and they makeup all of the visible universe. The standard model of particle physics has described the behavior of these elementary particles in precise detail.
BOSONS AND FUNDAMENTAL FORCES:
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| Four Fundamental Forces |
Standard model also hosts another type of particles called bosons. Bosons are force carriers.
There are four types of bosons plus a recently discovered Higgs boson. The most familiar boson is Photon which is an electromagnetic force carrier.
The four fundamental forces describe how the matter interacts with itself and bosons carry these forces. These forces are;
1: Electromagnetic force
2: Gravitational force
3: The strong Nuclear force (force which holds nucleus together)
4: The weak Nuclear force (responsible for beta decay)
Comparison of forces;
Forces
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Magnitude
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Range
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Particles/bosons
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The strong Nuclear force
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1
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10-15 (diameter of average nucleus)
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Gluons
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Electromagnetic force
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1/137
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Infinite
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Photons
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The weak Nuclear force
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10-6
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10-18 (0.1 % of diameter of proton)
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W+ and W-
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Gravitational force
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6×10-39
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Infinite
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Graviton
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Graviton is suppose to be a boson which is suppose to carry gravitational force but to date standard model has failed to produce such a particle.
In past years it has been very difficult to formulate a quantum theory of gravity. This has been one of the most difficult problem in theoretical physics. But string theory has come to the rescue and has provided a quantum theory of gravity.
THEORY OF EVERYTHING (TOE):
To date, there are two very powerful theories which describe how the universe works and how matter interacts. One is Quantum theory which describes the behavior of matter on microscopic scale and the other is General theory of relativity which describes how the world works on macroscopic scale. But the dilemma is that at some point both of these theories at times has failed to describe some phenomena's of nature e.g. when describing black holes. Another problem is that there is no way of connecting different theories to make a single unified theory.
For years physicists have been trying to develop a Grand unified theory or a “Theory of Everything” (TOE) i.e. a single theory which explains how the universe works. There have been many ideas for this but for some years string theory has been proven a worthy candidate.
WHAT IS STRING THEORY?
String theory gives a simple idea that even the most fundamental particles such as quarks and electrons are composed of something much smaller such as tiny strings. The strings mentioned here are just 1 dimensional constituents of planks length.
So suppose you have a very powerful microscope that could look even deeper into the electron then you would find inside that electron a loop of string oscillating at some frequency. Now those strings are present in every elementary particle, and in every particle it vibrates in a unique way. Suppose if it vibrates in electrons in some frequency then it would vibrate in an Up quark at a different frequency and so on.
So the string theory gives the idea that instead of the world being composed of different type of fermions and bosons, they are actually composed of strings.
As simple as it sounds this theory has proven very promising among physicists for the past few decades. However, to date there has been no experimental proof but it has been supported by mathematical equations.
MAIN ELEMENTS OF STRING THEORY:
STRINGS:
String theory gives us the idea that instead of the world being composed of point particles of zero dimensions, they are actually made of strings. Physicists believe that closed strings have properties that might describe gravity.
QUANTUM GRAVITY:
Theories that have made attempts to unify theory of relativity and quantum theory are called theories of quantum gravity and string theory has shown to be a very promising contender.
UNIFICATION OF FUNDAMENTAL FORCES:
String theory has made a very successful attempt in unifying the four fundamental forces. According to string theorists in early universe (when there were very high energy levels) all of these forces could be described as strings interacting with each other.
EXTRA DIMENSIONS:
According to string theory, instead of the world consisting of 4 dimensions ( x, y, z axis and time), we live in a world which have at least 10 dimensions. The other 6 dimensions are curled up (compacified in string terminology) to extremely small sizes that we can never perceive them.
SUPER SYMMETRY:
String theory predicts that super symmetry exists between fermions and bosons meaning for every boson a fermion exists and vice versa. Although these extra particles have not been yet detected.
If you're interested in Learning more about the String Theory , Models of TOE, 11 Dimensions, Supernovas, sub atomic particles and other exciting phenomenons which would give you a much better understanding in how the universe works, Then this book "The Elegant Universe" by renowned string theorist Brian Greene is a MUST READ for you.
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