String Theory is actually classified as a Theory of Everything. It means that String Theory is formulated or developed so as to explain each and every Phenomenon in the Universe and the theory has already been able to predict the Existence of Multiverses.
Einstein’s Equations clearly showed that Space is more of like a Multidimensional Fabric. His Equations stated that Space can be bend, BUT IT CAN NEVER BE TORN (RIPPED) APART.
The Importance of the String Theory is that it makes the Ripping/Tearing of the Fabric of Space-Time POSSIBLE. In order to Understand this better, you have to be able to look at the Changes in the Space-Time Fabric in the Atomic Level. The String Theory says that Einstein might be wrong about the Tearing of Space-Time.
In the Atomic Level, the Fabric of Space-Time is CHAOTIC and Rips and Tears in Space are considered to be common. Rips and Tears in Space should happen and it will eventually cause a COSMIC EXPLOSION. But that is not happening.
What is the Factor that prevents the COSMIC EXPLOSION during the Tearing of Space-Time?
The Answer to that Question is the STRING THEORY. String Theory shows that the Universe is made up of One-Dimensional Objects known as Strings. The String can either be connected to itself to form a Loop or it could just be a Single Strand. The Type of String that prevents the Cosmic Explosion from happening is the Connected one. When the String travels through Space-Time, it will form a Tube in it’s shape and the Tear in the Space-Time Fabric will be contained within that TUBE.
The String Theory makes it possible for Tears in Space-Time Fabric to happen. But the String Theory is not just limited to that.
The String Theory also predicts the Existence of Multiverses. The Theory explains that the whole Universe is just a Collection of many so-called Strings. All such Strings join together to form a thin Layer which represents our Universe. Our Universe could be similar to a Slice of Bread and there could be other Slices of Bread (Other Universes). And these Universes could be aligned with each other, but without any connection or link between each other. Scientists are not able to say for sure that any form of Connection or Transportation from One Universe to another is possible or not.