A dense nebula in which the Enterprise-D took refuge from a Borg cube in 2366, buying time for repairs before the Borg forced the ship out and abducted Captain Picard.
The Paulson Nebula is a cloud of gas and dust near the route the Borg took towards Earth in 2366. Its composition, rich in dilithium hydroxyls, magnesium and chromium, is enough to blind the sensors of a Borg cube.
In The Best of Both Worlds, the damaged USS Enterprise-D escapes a Borg tractor beam and Picard orders the ship into the nebula. The crew uses the respite to make repairs and to work on a plan to turn the main deflector into a weapon.
The Borg wait outside and eventually bombard the cloud with magnetometric guided charges, driving the Enterprise back into the open. Drones then board the bridge and take Picard, who is transformed into Locutus.