Nebula

A Nebula is a type of environment in the galaxy. There are four types of nebulae, all of which afflict a ship with negative effects.

Nebula effects

Name	Effects
Nebula	+300% Unrecognized icon name Move Cost
Dust Cloud	+100% Unrecognized icon name Move Cost, -100% Unrecognized icon name All Defenses, -50% Unrecognized icon name Sensor Power
Gas Cloud	+100% Unrecognized icon name Move Cost, -25% Unrecognized icon name Tactical Speed, -25% Unrecognized icon name Acceleration, -50% Unrecognized icon name Sensor Power
Radiation Storm	+100% Unrecognized icon name Move Cost, -25% Unrecognized icon name Hit Points, -50% Unrecognized icon name Sensor Power

There are several ways for a ship to become immune to nebulae.

Installing the Subspace Sensor or Environmental Shield Module on the ship
Installing an Unrecognized icon name Exploration Support System on a nearby starbase
The faction having the Starfaring ability