The number of universes is a topic of speculation and debate in the realm of cosmology and theoretical physics. The term "universe" typically refers to the observable universe, which is the vast expanse of space that we can currently observe and study. However, there are different ideas and theories that propose the existence of multiple universes beyond our own.
One concept is the multiverse, which suggests the existence of multiple universes coexisting alongside our own. These universes may have different physical laws, constants, or dimensions. The multiverse idea is often discussed in the context of inflationary cosmology and theories such as eternal inflation and string theory. However, it's important to note that the existence of a multiverse is still a topic of ongoing scientific investigation and is yet to be confirmed by empirical evidence.
As for what lies beyond the universe, it is a question that is difficult to answer definitively. Our current understanding of the universe is based on observations and measurements within the observable universe. Speculating about what exists beyond it is highly speculative and falls into the realm of metaphysics and philosophy.
Some cosmological models suggest that the universe may be part of a larger structure or a higher-dimensional framework. For example, theories like the "brane cosmology" propose that our universe could be one of many "branes" (membranes) existing within a higher-dimensional space.
Ultimately, the nature of what lies beyond the universe, if anything, remains an open question and an area of active exploration in both theoretical physics and philosophy.