Extra Dimensions : The String Theory

Introduction 

 The world as we know it has three dimensions of space - length,width  and depth and one dimension of time. But there's the mind - bending possibility that many more dimensions exist out there. Beyond these three visible dimensions, scientists believe that there may be many more. The development of string theory in early 1988 from studies of the problem of supersymmetry breaking by Antoniadis et al. In fact ,the theoretical framework of superstring theory posits that the universe exists in ten different dimensions. These different aspects are what govern the universe, the fundamental forces of nature and all the elementary particles contained within. Theories that suggest extra dimensions predict that,in the same way as atoms have a low - energy ground state and excited high - energy states, there would be heavier versions of standard particles called Kaluza - Klein States , would have exactly the same properties as standard particles but with a great mass. Kaluza et al and Klein tried to unify electromagnetic field originates from fifth component of a five dimensional metric tensor. 

String Theory

Theorists have  been working on the idea of string theory since the 1960s ,and one of the first things they realized is that for the theory to work, there have to be more dimensions than the four we're use to.

String theory is a purposed theory of everything that physicists hope will one day explain ........... everything. All the forces,all the particles, all the constants,all the things, under a single theoretical roof,where everything that we see is the result of tiny vibrating strings. 

In string theory ,little loops of vibrating stinginess manifest as the different particles and as the force - carriers of nature. The way they do so this is through their vibrations. Each string is so tiny that it appears to us, as nothing more than a point- like particle, but each string can vibrate with different modes. Each vibration mode is thought to relate to a different kind of particle. So all the strings vibrating one way look like electrons, all the strings vibrating another way look like photons , and so on. What we see as particle collisions are in the string theory view,a bunch of strings merging together and splitting apart.

According to string theory, the universe operates with 10 dimensions. But that raises a big question: If there are 10 dimensions then why don't we experience all of them or haven't detected them ? Lisa Grossman at ScienceNews reports that a new paper suggests ,an answer ,showing that those dimensions are so tiny and so fleeting that we currently can't detect them.

According to string theory, the fifth and sixth dimensions are where the notion of possible worlds arises. If we could see on through to the fifth dimension,we would see a world slightly different from our own that would give us a means of measuring the singularity and differences between our world and other possible ones. 

In the sixth ,we would see a plane of possible worlds,where we could compare and position all the possible universes that start with the same initial conditions (i.e Big bang theory), you could travel back in time or go to different futures. 

In the seventh dimension, you have access to the possible worlds that start with different initial conditions. 

The eighth dimension again gives us, a plane of such possible universe histories each of which begins with different initial conditions and branches out infinitely.

In the ninth dimension, we can compare all the possible universe histories, staring with all the different possible laws of physics and initial conditions. 

In the tenth and final dimension, we arrive at the point in which everything possible and imaginable is covered.

Demerits of string theory 

It's difficult to completely explain the mathematics behind string theory without putting on a graduate seminar or two but in essence dimensions fine through ten have to do with possibility and include all possible futures and all possible pasts including realities with a totally different physics than those in our universe. 

But for the math to work, there have to be more than 4 dimensions in our universe. This us because our usual space time doesn't give the strings enough 'room' to vibrate in all the ways they need to in order to fully express themselves as all the varieties of particles in the world. They are just too constrained.

In other words, the strings don't just wiggle, they wiggle hyper dimensionally. Current versions of string theory require 10 dimensions total, while an even more hypothetical uber - string theory known as M-theory requires 11. But when we look around the universe, we only ever see the usual 3 spatial dimensions plus the dimension of time. We are pretty sure that if the universe had more than 4 dimensions, we wouldn't noticed by mow.