The PBS program Nova aired a documentary called “Fabric of the Cosmos” which you can watch on pbs.org in the link provided.
The program stars physicist Brian Greene and is based on his book of the same name. The first part talks about what empty space really is and what it is made of.
It turns out that space is not as empty as we thought. The weight of empty space is 70% of the weight of the universe. This ingredient of empty space is called dark energy and it is causing our universe to be expanding and the expansion is accelerating.
We learned that mass can wrap and twist space like a fabric. We learned that space is bubbling at the quantum level as evidenced by the Casimir effect. Scientist are now looking for the Higgs particle.