Indeed, the one force that holds the universe together, that makes everything possible, and all we really know about it is the effect we witness. I can take two golf balls, place them 40,000 miles apart, and somehow they interact with each other. If no particles pass back an forth, how is that possible. I don't think they have even determined what the speed of gravity is.
Hmmm, the article mentions gravitons, and a condensate. Makes me wonder if they’re bringing up the old fashioned concept called aether. Supposedly Einstein couldn’t get his relativity theory to work with it, so he just left it out.