>>>GRAVITATIONAL ANOMALY DETECTED<<<
Magnetic and gravimetric readings are consistent with a Jump Hole -- a natural phenomenon that functions similar to a Jump Gate, though the hazards associated with traveling through a Jump Hole remain largely unknown. Ageira Technologies recommends avoiding all contact with Jump Holes.
Note: Despite the warning, jump holes are completely safe for the player to use at any time. It is theorized the warnings placed on them are a product of in-story lobbying efforts from Ageira (as they are a threat only to the company's own Gate-building business). However, no Jump Holes are served by Trade Lanes (Ageira's influence again), making them so inconvenient to use that it's generally best to stick with the Gates anyway. Holes tend be far away from anything, necessitating a long flight through open and often criminal-controlled space.
Your navmap also flatly refuses to run a "best path" through a jump hole, even if there's no other way into a system, so you'll have to plot such paths manually. However, if you select a best path that could skip systems by using Holes, the universe map will show both the regular and hole-using paths, which is helpful for manual path plotting.
"The law has the regular routes locked down most of the time. The only way to really get around is by using the jump holes. It's one of our many advantages over them."