Hyperstream

A hyperstream, also called a slipstream, was a natural phenomenon created by certain trans-dimensional moving objects. Such an object could move in and out of hyperspace at speeds faster than those attainable by any starship. In their wake, they pulled along vapor and other matter behind them, creating a hyperstream. The hyperstream gave the object the appearance of a comet with a tail. A starship could take advantage of this phenomenon, but such travel was unreliable: there was no way to tell where the cometary body was moving. It also carried risks. Passing by a heavy mass, like a planet or sun, could not only divert the comet's path, but also rip it apart along with the ship it was towing along.

In 0.5 ABY, Luke Skywalker and C-3PO were flying a smuggling ship for the Rebel Alliance through an Imperial blockade. Imperial pilots spotted them, and their ship was damaged and outnumbered. There was a trans-dimensional comet in the vicinity, and Skywalker saw it as their only means of escape. Over Threepio's objections, he maneuvered close to the object until their ship became caught in its wake and whisked away. As the cometary body approached the planet Hoth, the planet's gravity began to break it apart. Skywalker had to skillfully fly the ship out of the slipstream before it was destroyed, then maneuver around the fragments of what had become a meteor shower. The starship crashed on the surface, but both occupants survived. Skywalker later was able to recommend Hoth as a location for the Alliance's new base.

Text and facts from the “Hyperstream” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.