Matter itself doesnt' go through subspace. I don't have a link for that one but there are theories where sub-space is a concept of all particules throughout the universe resonating to one-another and can be affected for communication purposes, but not travel.
Correct me if I'm wrong. We can all agree that Dune is science fiction.
But didnt dune employ some kind of hyperspace travel, where a navigator, controls the trajectory of one's travel in "hyperspace"?
But then again there are alot more explanation behind the concept. Then the simply RED MATTER creates blackholes.
Actually, Dune left the explanation at "We can fold space because of the Spice; you literally have to be on drugs to understand how this works."
Remember the Guild Navigators consumed so much Spice they actually evolved into giant seahorses or something. Exactly how THIS happens is left mostly unexplained, and probably for the best, because I think it would detract from the story if Frank Herbert wasted too much page space going into the details on that.
From what I understand Dune, there is a giant space folding generator that's attached to the ship. The spice only allows the navigator to perceive, the "hyperspace" it travels in, so the ship can be safely guided out of "hyperspace" and into a destination that you want.