Assertion: boomerang nebula | /r/HasProperty | the ultraviolet rays
Facets:
value: in older planetary nebulae
type: LOCATION
Source sentences:
text: This simply means that the Boomerang Nebula is very young because, in older planetary nebulae, it is the ultraviolet rays emitted by the central white dwarf stars that make the gasses of the nebulae glow brightly.