The most widely accepted theory about the origin of the universe is the Big Bang Theory. This theory posits that the universe began approximately 13.8 billion years ago from an extremely hot, dense state and has since been expanding. The Big Bang Theory is supported by observational evidence, such as the cosmic microwave background radiation and the redshift of distant galaxies. It provides a comprehensive framework for understanding the evolution of the universe, including the formation of galaxies, stars, and chemical elements in the early stages of cosmic history.