The whole thing begun in 1968 when Gabriele Veneziano, who worked at CERN in Geneva, discovered that the Euler Beta function is quite suitable to explain the physical properties of strongly interacting particles. Working further on this concept scientist all over the world came to a conclusion that all observed elementary particles in fact are vibrating 1-dimentional closed circuit strings. The more intensive the vibration – the more massive particle we will observe. After the years of theoretical research this simple idea transformed into a so called “string theory”, one of the most complicated and promising branch of modern theoretical physics and astrophysics.
The advantages of the theory are obvious. It vanishes dozens of known particles studied by nuclear physics and gives only one universal object with definite properties – string. It means that all known forces can be described in the terms of one theory instead of four we are using now. Furthermore the theory is expected to unite gravitation (general relativity theory) and principles of quantum mechanics what seems impossible within any other known theory. It also tends to describe astronomy and cosmology (which is mostly about gravitation) in a completely new way.
But there are some predictions the string theory makes which are quite unusual for understanding for now. It occurs that they can exist only in 11-dimentional world to produce the reality we are currently living in with all its known physical laws. As we got used to think we are living in 4-dimentional world and can’t even imagine more than 3 dimensions – it’s a kind of a problem to get used to 11.