What is a nebula (in astronomy)?

Between their formation process, their role in stellar and planetary formation, and their diversity, nebulae have provided humanity with endless intrigue and discovery. For some time now, scientists and astronomers have been aware that outer space is not really a total vacuum. read more

noun: nebula; plural noun: nebulae; plural noun: nebulas. Astronomy - a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter. (in general use) any indistinct bright area in the night sky, for example, a distant galaxy. read more

Nebula Formation: In essence, a nebula is formed when portions of the interstellar medium undergo gravitational collapse. Mutual gravitational attraction causes matter to clump together, forming regions of greater and greater density. read more

A nebula (Latin for"cloud" or"fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, nebula was a name for any diffuse astronomical object, including galaxies beyond the Milky Way. read more