What is the main difference between the steady state model of the universe?

The steady state model of the universe proposes that the universe is eternal and unchanging on a large scale, with matter continuously created to maintain a constant density as it expands. In contrast, the Big Bang theory posits that the universe originated from a singular point and has been expanding and evolving over time since that initial explosion. The steady state model emphasizes a uniform and infinite universe, while the Big Bang theory suggests a finite age and a dynamic evolutionary process. Ultimately, observational evidence, such as cosmic microwave background radiation, supports the Big Bang theory over the steady state model.