Space in physics is described as a framework for understanding the universe, particularly through the lens of general relativity, where space-time is not merely a backdrop but can be curved by mass and energy. In a hypothetical scenario with two large masses moving apart, the concept of vacuum arises, indicating that space exists even in the absence of matter. The universe's geometry can be classified as open, closed, or flat, with current observations suggesting it is "pretty darn flat," although the exact nature remains uncertain. The relationship between matter and space is complex, as matter influences the curvature of space-time, and discussions highlight that space can exist without matter, but its properties may differ. Overall, the exploration of space involves cosmological models that continue to evolve with ongoing research and observations.