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"
The Southern Cross in a Southern Sky
19/10/2015
Have you ever seen the Southern Cross? This famous constellation is best seen from Earth's Southern Hemisphere. Captured from Rio de Janeiro, Brazil, the four bright stars that mark the Southern Cross are visible just above the horizon in the featured image. On the left of this constellation, also known as The Crux, is the orange star Gamma Crucis. The band of stars, dust, and gas rising through the middle of the image mosaic is part our Milky Way Galaxy. Just to the right of the Southern Cross is the dark Coal Sack Nebula, and the bright nebula at the top of the image is the Carina Nebula. The Southern Cross is such a famous constellation that it is depicted on the national flags of Australia and New Zealand. Follow APOD on: Facebook, Google Plus, or Twitter