The question of whether people from another universe can cross over to our universe is highly speculative and falls within the realm of science fiction and theoretical physics. While there are various theories and concepts that explore the idea of multiple universes, such as the multiverse hypothesis, parallel universes, or bubble universes, the scientific consensus remains that these ideas are still speculative and lack empirical evidence.
In theoretical physics, some models, like certain versions of string theory, propose the existence of additional spatial dimensions or parallel universes that are disconnected from our observable universe. However, if such universes exist, the possibility of crossing over or interacting with them is largely unknown and would depend on the specific nature of those universes and the laws governing them.
At present, our understanding of the universe is limited, and much research and exploration are required to uncover its true nature. While the idea of crossing over to other universes might be fascinating from a conceptual standpoint or in works of fiction, its scientific feasibility and the mechanisms involved remain speculative and unexplored.