Mass shadow

In hyperspace, a mass shadow was the gravitational signature of a large object in normal space. Since those shadows were potentially lethal to any starship traveling too near, it was necessary to avoid colliding with them by plotting precisely calculated hyperspace jumps. By simulating the gravity shadow of a celestial body, a ship's travel through hyperspace could be halted or their jump to hyperspace rendered impossible within an interdiction field.

During the Imperial Era, the main star of the Throffdon system went supernova and formed mass shadows. As smuggler Han Solo was en route to Gwongdeen, his ship, the Millennium Falcon, was pulled from hyperspace by the Throffdon star's mass shadows. The Galactic Empire was rumored to have developed a superweapon called the Mass Shadow Generator, which could exist in space and hyperspace simultaneously.

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