First of all, I completely understand your confusion about string theory. It is a complex and abstract concept that is still being explored and understood by scientists. However, I believe that the beauty of science is that it constantly challenges our understanding and pushes us to explore new ideas and theories.
One of the main reasons why string theory is considered superior to traditional theories like General Relativity and Quantum Mechanics is because it attempts to unify them into one comprehensive theory. GR and QT are both highly successful in their own domains, but they have fundamental differences that make it difficult to reconcile them. String theory, on the other hand, provides a framework that can potentially incorporate both theories and provide a more complete understanding of the universe.
As for the concept of branes, it is a crucial aspect of string theory that helps explain the origin of the universe. It suggests that our universe is just one of many parallel universes existing on different branes, or membranes. This idea may seem strange and even unsettling, but it is based on mathematical models and has gained support from various experiments and observations.
I understand your child's questions about the origins of the universe, and it is a question that scientists have been trying to answer for centuries. While we may not have a definitive answer yet, theories like string theory and branes offer a potential explanation that is supported by scientific evidence.
So, while string theory may seem like a complicated and mysterious concept, it is a valuable tool in our pursuit of understanding the universe. And who knows, perhaps one day we will have a better understanding of it and be able to answer your child's questions with more certainty. But for now, let's just enjoy the Halloween festivities and leave the mysteries of the universe for another day. Happy Halloween!