Saturday, 23 June 2018

STRING THEORY : THE THEORY OF EVERYTHING

         STRING THEORY : THE THEORY OF                               EVERYTHING



The world we live in is rapidly changing with resources being depleted and consumers being increased. The climatic conditions are getting worse and everyday we discover something new that may pose threat to our mother earth. So we must keep expanding our knowledge of universe to discover new possibilities of our existence in this universe or i should say in this multiverse.  For acquiring a better  picture of this universe, we must posses a better understanding of its fundamentals or building blocks. We need to bridge the gap between our classical world and the quantum world and the bridging must be done by a single theory like a single thread that binds all the pearls of a necklace together. 
So to present a better and radical picture of this universe many theories were proposed and examined by renowned names in the field of science. Their main purpose was to combine all the four fundamental forces of nature (gravitational force, electromagnetic force, strong and weak nuclear force ) so that they may be explained by a single theory, a single law to govern the universe. The most successful theory among them is STRING THEORY. 
Origin of this theory can be traced back to 1968 when Gabriele Veneziano accidentally discovered a 200 year old mathematical equation that seemed to describe strong nuclear force and he published it. This equation faced some advancements and later came to be known as string theory. Physicists could never accept it totally because its predictions and assumptions were too radical to be accepted furthermore it wasn't possible to prove it experimentally. But some scientists took a leap of faith and here it is, one of the best theories we have today.
It predicted the existence of one dimensional vibrating strands of energy called strings and those strings required extra dimensions of time and space for its movement. It required 9 dimensions of space and 1 dimension of time for its movement often called as degrees of freedom with all these extra dimensions being curled up together and present at each point in space. These strings are fundamentals of universe and they are so incredibly small that if an atom were enlarged to the size of the solar system then a string would only be as large as a tree. The different ways in which these tiny strings vibrate gives different properties to particles. Each particular pattern of vibration gives birth to a particular property like charge, mass etc. It also predicted some mysterious mass-less particle that was never seen before in nature. These particles seemed to be describe  gravity at quantum level (quantum gravity) . Later those particles were discovered to be "graviton". 
The mathematical equation of this theory had 10^500 solutions and also there were 5 different versions of this theory each one facing different anomalies. In 1995, at the university of Southern California Edward Witten forwarded his work in which summarized all these versions into a single one known as M THEORY though no one knows what that M means, also called as unified field theory.  He believed that these different versions of theory were nothing but different ways of looking at a single theory. M theory predicted even one more dimension of space making the total sum 11 (10 dimension of space and one dimension of time). The newest version made the picture clearer and eradicated anomalies that followed string theory. It gives a nice try to unite general relativity and quantum mechanics.  M theory  allows a string to stretch to a membrane or just BRANE that could be 3 dimensional or even be of more dimensions and with enough energy it could grow to the size of universe. This theory also supports the existence of parallel universes (if universe is considered a slice of bread then there must be other slices of bread when we talk about a loaf of bread ). The universe is considered as a membrane and everything sticks with it allowing nothing to escape. 
                         


It predicts that all the matters comprise of open strings having their both ends tied to the 3-d membrane so that they can't leave it but graviton are made of closed vibrating strings allowing it to travel other dimensions and universes which of course gives an answer to a very famous question that '' why even after being so powerful  and dominating force gravity seems very weaker than other fundamental forces of nature? '' . The answer is obvious, escaping of universe by graviton dilutes the strength of gravity. 
Further the supporters of string theory propose that the possibility of communication with other civilizations can be accomplished with these gravity particles in the form of gravitational waves.




 It also tries to explain what caused the BIG BANG using the concept of multiverse, predicting it to be caused by collision of universes or the fissioning of universes(if we consider our universe to be a soap bubble then we know that a new soap bubble is formed when two bubbles merge and two bubbles are formed when a single one splits, big bang can be considered either to be splitting or merging of universes and we are trapped in the universe like insects are trapped on the surface of a soap bubble  ) .
Today we have some prominent physicists working upon this theory and one of them is Michio Kaku, a professor of theoretical physics is a specialist in string theory. His strong belief in this theory made him devise a single short mathematical equation for this theory- 
               
            

This theory still keeps surprising physicists with not only its predictions but with the very large portion of our world(both , the one we see and the one we don't) it can describe.  
                                     
                                            Thank you