The question of whether the universe is infinite or not is still an open and active area of scientific investigation. Our current understanding suggests that the universe could have one of three possible geometries: flat, positively curved (closed), or negatively curved (open).
If the universe is flat or open, it could potentially extend infinitely in space. In this case, the universe would have no boundaries, and it would continue indefinitely without an end. However, determining the exact geometry of the universe on a cosmic scale is a challenging task, and further observations and data are needed to make more precise conclusions.
On the other hand, if the universe is positively curved, it would have a finite volume and would wrap back onto itself. In this scenario, the universe would be closed and finite but still without any distinct "beyond" or boundary.
It's important to note that when scientists refer to the universe as infinite, they are typically referring to the observable universe—the portion of the universe that we can currently observe. This observable universe is limited by the finite speed of light and the age of the universe, which means there are regions beyond our observational reach. However, the term "infinite" in this context does not imply that the entire universe itself is necessarily infinite.
To summarize, whether the universe is infinite or not is still an open question in cosmology. Scientific investigations continue to explore the nature, geometry, and size of the universe, and future discoveries may provide more insights into its true nature.