The concept of the "universe" typically refers to the entirety of space, time, matter, and energy as we know it. When we say "outside the universe," it can be a bit misleading because the universe, by definition, encompasses everything we are aware of.
However, it's worth noting that the observable universe is a smaller portion of the entire universe that we can currently observe. The observable universe is limited by the distance that light has had time to travel since the Big Bang, given the age of the universe and the finite speed of light. This observable universe is estimated to be about 93 billion light-years in diameter.
The expansion of the universe has caused distant regions to move away from us at speeds greater than the speed of light. As a result, the light from those regions cannot reach us, effectively limiting our observation. Therefore, there may be regions or objects beyond our observable universe that we are currently unable to detect or observe.
It's important to keep in mind that our understanding of the universe is based on scientific observations and theories, which are subject to revision and refinement as we gather more data and knowledge.