To understand the behavior of our universe two type of Theory are used.

  1. General Theory of Relativity.
  2. Quantum Mechanics.
Einstein describe the General Theory of Relativity. This theory is used for understand about biggest thing like planets, sun moon etc. Quantum Mechanics Theory describe about tiny particles like atom, electron, proton etc. These two theories do not work together because these two theories are different from each other. Here we needed a theory that would help us understand this universe at every level.

Sting Theory

Imagine you have an apple and you asked yourself What is the apple made of how do you answer that question? Well, you want to look deeply inside the apple. So, you Magnify it and you magnify it again and if you keep on doing it deep inside eventually, you begin to see molecules come into view but molecules are not the end of the story because the molecules you can enlarge them and if you make them big enough deep inside, you begin to see Atoms, atoms are not the end of the story too because we have electrons Zooming around the nucleus deep inside mostly empty space in the atom, but deep inside We see the nucleus. So if you grab that and magnify it you see that the nucleus is itself made of particles neutrons and protons and if you grab one of the neutrons and magnify it you find yet further particles little tiny quarks inside Now that is where the conventional idea stopped String theory comes along and suggests that inside these particles there is something else So if you take a little quark and you magnify it conventional idea says there's nothing inside but string theory says I'll find a little tiny filament a little filament of energy a little string like filament and just like the string on a Violin, you pluck it and it vibrates Creates a little musical note that you can hear the little strings in string theory when they vibrate They do not produce musical notes. They produce the particles themselves so what quark is nothing but a string vibrating in one pattern an electron is nothing but a string vibrating in a different pattern a neutrino. Nothing but a string vibrating and different patterns still so if you take all this back together, you have my ordinary apple and if these ideas are right, they are speculative but if they are right deep inside the apple or any other piece of matter There's nothing but a dancing vibrating cosmic symphony of strings. That is the basic idea of string theory. 

Sting theory

String theory and Dimension

According to Sting theory ten dimension are in this universe. But when we talk about our world there is only three dimension.