How do quantum mechanics, string theory and relativity influence our understanding of the universe?
What are the implications of combining quantum mechanical phenomena, string theory, and Einstein's theory of relativity for understanding the fundamental nature of the universe, and how could these insights be combined into a unified theory?
Quantum mechanics and relativity theory do not influence our understanding, but are the result of what we have understood. String theory is generally useless as it does not make predictions. How to bring them together? – No one knows that, otherwise we would have done that.
Unfortunately, this remains a nice wish, since it cannot be brought under a hat, or it is theories that remain theories due to the lack of hand-resistant evidence.
even if with the cosmic background radiation of 2.725° kelvin there is a proof that it before approx. 13,7 billion years must have started.