What is Reflection nebula?
[[File:reflection.nebula.arp.750pix.jpg|thumb|200px|<nowiki>[[IC2118]] (the </nowiki>[[Witch Head Nebula|Witch Head reflection nebula]] 1000 [[light years]] from Earth), is caused by the bright star [[Rigel]] in the [[constellation]] [[Orion (constellation)|Orion]]. The nebula glows because it reflects light from Rigel. Dust in the nebula reflects the light.]] In [[astronomy]], a '''reflection nebula''' is a cloud of dust which reflects the light of a [[star]] or many stars. The light from the nearby stars is not hot enough to [[ionization|ionize]] the [[gas]] of the nebula to make an [[emission nebula]]. However, is enough to make the dust visible because the light [[reflection|reflects]] off of the dust. Reflection nebulae are usually blue because the [[Rayleigh scattering|scattering]] works better for blue light than red (this is the same reason that the [[sky]] is blue and [[sunset]]s are red). Reflection nebulae and emission nebulae are usually seen together and sometimes are called 'diffuse nebulae'. A good example of this is the [[Orion nebula]]. Reflection nebulae may also be the site of [[star formation]]. ==Related pages== * [[Variable nebula]] == References == * James B. Kaler (1998). ''Kosmische Wolken. Materie-Kreisläufe in der Milchstraße.'' Spektrum Akademischer Verlag. [[Category:Nebulae]]