The possibility of another Big Bang occurring inside our existing universe is an intriguing question that has been explored within certain cosmological models. However, it's important to note that these ideas are still speculative and highly theoretical, and they go beyond our current empirical understanding of the universe.
One speculative scenario is known as "eternal inflation" or "chaotic inflation," which suggests that our universe is just one of many bubble universes continuously forming within a larger multiverse. According to this hypothesis, each bubble universe undergoes its own expansion and may experience its own Big Bang-like event, giving rise to new regions of space-time.
If such an event were to occur, it could have profound consequences for the affected region. The newly formed universe within our existing universe would likely have its own physical laws, constants, and possibly different properties compared to our known universe. It might have its own set of galaxies, stars, planets, and possibly even life forms.
However, it is essential to emphasize that these ideas are highly speculative and currently beyond the realm of observational evidence. They are based on theoretical models and mathematical frameworks that attempt to address fundamental questions about the origin and nature of the universe. As our understanding of cosmology advances and new evidence becomes available, scientists will continue to explore and refine these ideas.