If we can think of space as a form of matter some very interesting things happen. Let's start with a piece of 2 dimensional space like a peice of paper. If you draw a 2 dimensional man on this paper, what does he do? He doesn't do anything. He just sits there. In order to make him move you have to draw another picture of the 2 dimensional man on another paper and then another and so forth. Then flip through them in rapid succession like an old fashion cartoon and the man moves around.
The old fashion cartoon is something like the propagation of a wave. Think of how a sound wave works. Take one cycle of a sound wave.
It begins at a point(big bang?) and propagates in all directions like an expanding soap bubble as each generation of air molecules transmits energy to the next generation of air molecules. This soap bubble is practically a two dimensional space but is curved into the shape of a sphere. In this way three dimensional air molecules form a two dimensional 'spacetime'. Now we can extrapolate upward to an element that exists in 4 dimensional space. When a wave propagates through an element that exists in 4 dimensional space it forms a 3 dimensional 'spacetime'.
We can think of spacetime as something like the pattern that is formed by the propagation of a wave through an element that exists in a higher dimension of space.
This can help us understand why space is curved, why energy is quantized, what constitutes the arrow of time, dark matter, dark energy, and the expansion of the universe.

Dave W.