A massive star that is not only bright and blue, but also emitting a fast stellar wind of ionized gas, created this huge space bubble. The energetic starlight then ionizes the shell, causing it to glow. The Bubble Nebula is about 10 light-years across and visible with a small telescope towards the constellation of Cassiopeia. Photographic 3-colour composition from the Isaac Newton Telescope. Reflection Nebulae Reflection nebulae are clouds of dust which are simply reflecting the light of a nearby star or stars.
Reflection nebulae are also usually sites of star formation.
They are usually blue because the scattering is more efficient for the blue light. Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae. Photographic 3-colour composition from the Isaac Newton Telescope. Dark Nebulae Dark Nebulae are clouds of dust which are simply blocking the light from whatever is behind. Dark nebulae are often seen in conjunction with reflection and emission nebulae.