The String theory

What is string theory?

But before starting this article one thing must be kept in mind that there exists a possibility for an unproven theory that 100% of it could be wrong. But then one would think that why are we reading it anyway. The simplest reason is that once every great discovery had been a theory.

Introduction

Imagine you’re holding something in your hands like a rope. What is it made of? You would say that it depends upon the type of rope we are talking about like jute, plastic or whatever but what is that made up of. Magnifying the idea very closely we can say molecules. But what are molecules made of – atoms. And on dividing atoms we can find even smaller particles, elementary particles; the electrons, neutrons, protons. And only a few years ago we have become familiar with the fact that even elementary particles are divisible. Quarks or leptons make them up. And that is where our idea stops. We can see any object because it reflects light but anything beyond quarks get so small that for the light waves it is not possible to touch them and get reflected back. Light just passes over them. That is why we cannot see them. This is the reason people believe that quarks, the elementary particles which make the electrons, neutrons and protons are the most fundamental particles of the Universe. But to some physicists it is the same belief like the one which used to be that an atom is indivisible. But here we are. They say that even quarks are made up of something and that is where the idea of string theory turns up. The string theory says that inside a quark you might find a little string of energy. That string might be closed, open, stretched or like a loop or something constantly vibrating. And the pattern of those vibrations is what that makes particles or we can say differentiate one particle from another. 

In the above image you can see that how a different manner of vibration makes different particles.

 

 

 Like as Professor Brian Greene of Columbia University says that these vibrations are same as those vibrations produced by a guitar string. But rather, as the guitar vibrations produce musical notes; these strings on the other, hand create particles. For example, the neutrino is nothing but a closed string vibrating in a different manner than an electron.

Scientists like Hawking and Einstein all throughout their lives tried to find the theory of everything and this string theory can be considered to be the basis of that.

 

Mediating particles

 

Have you ever wondered about “forces” that act between particles? I mean like there are four fundamental forces, but what factor cause these forces. Are there any particles which make these forces happen? Yes, all the forces that exist in nature whether strong or weak are carried by particles. These particles are known as mediating particles. The mediating particles for the four fundamental forces of nature are –

Fundamental forces	Mediating particles
Strong nuclear force	Gluon
Weak nuclear force	W,Z Boson
Electromagnetic forces	Photon
Gravitational force	Graviton (hypothetical)

Photon, the mediating particle of EM forces was earliest to be discovered in 1905 by Einstein. While the Bosons are the latest to be discovered, named after the Indian scientist S.N. Bose.

Superiorities

The main target of this theory is not to justify the fundamental nature of matter but to establish a relation between quantum gravity and general relativity. And if we can join the laws of general relativity and quantum mechanics, it will give us the theory of everything. The Universe then will no longer be a mystery. But what exactly are we talking about these two things –

Quantum mechanics – This is the set of mechanism for particles or matter at the atomic or molecular level dealing with particle physics. As far as we know, all four fundamental forces work everywhere in the Universe (leaving exceptions aside like black holes), even at the quantum level but not gravity. Any theory had never been able to prove or notice gravity at quantum level. So in knowledge of our intellect quantum gravity does not exist.

General relativity – This is an Einsteinian theory (devised by Einstein). Einstein tried to explain and introduce many phenomenons through it and gravitational warp was one of them. Gravitational warp is like a ripple in spacetime. According to relativity, gravity is the curvature in space which causes an object to attract another object. This phenomenon can be understood well from the image below.

In this picture, if you try to imagine the surface as space (or spacetime) you can see well that how a heavier object warps the fabric like spacetime around it to attract a lighter object. This is what causes gravity as per relativity.

So, string theory tries to unite these two theories on the quantum level which is probably one of the most prominent problems of theoretical physics. But the real fact is that it had already combined these two things, mathematically. The thing left to do is to verify it experimentally which is not possible practically. And also, this mathematical derivation was not made possible on the first day of this theory obviously. In the beginning, when the string theory was not working under normal conditions, more dimensions were introduced and the concept of adding more dimensions made the maths completely justified.

Complexities

Now, the question is if this theory is so efficient then what are the odds that stand against it. Like, if the physicists are working on it for decades then why had they never been able to prove it?

We should know that the discovery of quarks was only made possible with the help of the particle accelerator. There is no direct method or any simple microscope kept out there in the laboratories through which we could peep into an atom.

Also, string theory has developed through time based upon different ideologies of different persons. The basic string theory can be proved mathematically but for that to work it will need more than 3 spatial dimensions (the ones in which our Universe works). Yes; 5 models of string theory talk about presence of 10 spatial dimensions whereas the sixth model says that there are 26 dimensions in the known Universe. All these theories altogether are known as the M theory (the term first to be used by Edward Witten).Special theory of relativity talks about time being the 4^th dimension. And this  is what makes the theory complex beyond imagination.

This was the simplest way in which I tried to explain the string theory. I hope  you liked it.