A nonluminous nebula of dust and gas that is observable because it obscures light from other sources.
- ‘In the Cigar Galaxy, there are blank spots where it appears there are not any stars, just dark nebulas.’
- ‘Both dark nebulas and luminous nebulas are considered likely sites for the processes of dust-cloud condensation and the formation of new stars.’
- ‘These dark nebulas are places where new stars are beginning their gravitational collapse and have yet to begin nuclear fusion.’
- ‘In the inner regions of dark nebulae important events take place, such as the formation of stars and masers.’
- ‘There are different forms of nebulas, dark nebulas, emission nebulas and celestial nebulas.’
- ‘For nebulas there are emission nebula, reflection nebulas, planetary nebulas, dark nebulas and supernova remnants.’