plural of spiral nebula

plural of radio nebula

plural of dark nebula

plural of emission nebula

(astronomy) A diffuse nebula visible in the night sky below Orion's Belt; it is approximately 40 light years across. It is one of the brightest nebulae visible to the naked eye and is the closest region of stellar formation to Earth.

(astronomy) A nebula that consists of dust which reflects starlight and appears blue in photographs.

(astronomy) A type of nebula that does not emit or reflect (visible) light, and thus obscures light sources behind it.

(astronomy) A nebulosity surrounding a dying red giant, consisting of material expelled by the star.

(astronomy) A nebula composed of ionized gases which produce visible light (as distinct from a reflection nebula, which reflects the light produced by neighboring stars).

(astronomy) Any nebula that emits radio waves