C-Black Holes

A Black Hole is a collapsed star. Black Hole systems are rare(1.5% chance if Random Stars is selected, and they are 80/63623 systems on the Real Stars list, for a 0.13% chance), and as they have high stellar masses, they are difficult to gravsurvey. They also have no planets. However, larger black holes get bonus jump points, on top of the additional jump points that any massive star gets, which means that they can offer access to a large number of new systems once you can fully survey them. [1]

Unlike in VB6, black hole systems have no special dangers.

In gameplay terms, a black hole tends to be a "speed bump" to exploration initially, as they are large and difficult to survey. They also tend to be difficult to cross even once they are surveyed, sometimes taking months for ships to fly between different jump points. (The lack of planets also makes this more difficult, as there are no Lagrange Points to speed up travel.) But they can be a major nexus of the jump network, especially later in the game as ship speeds increase.