Nebula
A nebula is a giant cloud of gas (mostly hydrogen and helium) and cosmic dust situated between stars in the interstellar medium. Nebulae serve as sites of stellar birth and death—including emission nebulae that glow from ionized gas, reflection nebulae that scatter starlight, and dark nebulae that obscure background stars.
Source: science.nasa.gov
APODs including "Nebula"
Camera Orion
21/03/2018
Do you recognize this constellation? Although it is one of the most recognizable star groupings on the sky, Orion's icons don't look quite as colorful to the eye as they do to a camera. In this 20-image digitally-composed mosaic, cool red giant Betelgeuse takes on a strong orange tint as the brightest star at the upper left. Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the lower right, and Bellatrix at the upper right Lined up in Orion's belt are three stars all about 1,500 light-years away, born from the constellation's well-studied interstellar clouds. Below Orion's belt a reddish and fuzzy patch that might also look familiar -- the stellar nursery known as Orion's Nebula. Finally, just barely visible to the unaided eye but quite striking here by camera is Barnard's Loop -- a huge gaseous emission nebula surrounding Orion's Belt and Nebula discovered over 100 years ago by the pioneering Orion photographer E. E. Barnard. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter