My English Diary: String Theory

Last week we spoke about what string theory is and why this theory is important.

To understand string theory, it's important to know that the universe consists of four forces:

• gravity
• electron-magnetism
• weak nuclear
• strong nuclear

To describe the universe's laws, physicists have made two fundamental theories:

1. the general theory of relativity(originated by Einstein's mind) is a theory which describes the rule of the universe at the grandest scale;
2. quantum physics studies the very smallest objects in nature; 

String theory attempt to unify the four forces in the universe with quantum physics and relativity laws into one unified theory.

String theory is a work in progress but now the key string theory feature includes:

• all objects in nature are composed of vibration filament (string) and membrane (branes) of energy;
• this theory attempt to reconcile general relativity with quantum physics;
• a new connection (called super-symmetry) exists between two fundamentally different type of particles: bosons and fermions. Under super-symmetry a fermion must exists for every boson and vice-versa. At now these extra particles haven't detected;
• extra dimensions to the universe must exist but usually invisible (unobservable);
• parallel universe can be possible;

But why is string theory so important?

We don't know. Today string theory probably has no practical application. Although we spend billion of dollar on particles accelerator or research of satellite programs. This is no reason to think that string theory can give us something practical, bat this is the physics theories.

In 10 years this theory might open the door to new incredible technology.

Link: Michio Kaku: The Universe in a Nutshell