How are galaxies, clusters, and nebulas different?

1 Answer

Nebula: Interstellar Clouds of Dust, Gas, or Both; Clusters: Please define; Galaxies: Stars, SNR's, Blackholes, Star Clusters, you name it held together by gravity.



  • Collections of dust, gas, or both.
  • Do not emit light themselves
  • There are five types;

#1.# Reflection (Collections of dust/gas that reflect light)

#2.# Emission (Same thing as Reflection but are illuminated by the microwave radiation from a nearby star(s))

#3.# Planetary (which has nothing to do with planets-rather it's remnants of a low to medium mass star {akin to Supernova, but WAY different})

#4.# Super Nova Remnants (SNR's) (Remnants of Supernova-Like Planetary Nebula)

#5.# Dark Nebula ( Same as Reflective & Emission but they block out all light from behind)


  • There are lots of types of Clusters, ranging from;
  • Star clusters (Clusters of stars)

  • Galaxy Clusters (Clusters of Galaxies)

  • Basically Clusters of anything


  • Basically "gravitationally bound" stuff. By stuff I mean everything above and more (except galaxy clusters {Correct term: Galaxy Superclusters})