We tend to think of space as a fundamental part of reality's architecture: it's where everything is located. But that reflects an outdated, classical intuition.
New view: These days we know that quantum mechanics provides a more accurate view of the world. According to quantum theory, the world isn't actually made of "objects" with "locations" in three-dimensional "space." Those are simply convenient ways of talking about features of an abstract and more fundamental description of the universe: the wave function. It evolves in a mathematical realm with more than 10^(10^100) dimensions. That's an absurdly large number, which should just make you think "Wow, that's a lot of dimensions."
In this view, ordinary space is like "temperature" or "wetness" – not a fundamental category, but a useful approximation we invoke to describe a tiny sliver of reality.
Bottom line: Physics has a long way to go before we understand how space emerges from quantum mechanics, but we shouldn't be surprised that the fundamental nature of stuff is something very different from what we're used to.
Other voices in the conversation:
- Izabella Laba, mathematician, University of British Columbia: We can work with space without understanding its essence
- Bridget Falck, astrophysicist, University of Oslo: Space is a relation between things, not a thing itself
- David Albert, philosopher, Columbia University: Maybe there is no space