There are multiple artists named Nebula:
1) Nebula is a psychedelic / stoner rock band formed by guitarist Eddie Glass and drummer Ruben Romano upon departing Fu Manchu in 1997. Mark Abshire soon joined as the band's original bassist. Nebula have been on indefinite hiatus since early 2010 but have not broken up.
2) Nebula was an ambient supergroup based in Italy. Nebula was founded in 2002 as an open ensemble by Gianluigi Gasparetti (aka Oöphoi) Read more on Last.fm