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 Toby Jug Nebula
05/01/1996
Is the only thing unusual about this nebula its shape? Pictured above is the IC 2220 - the Toby Jug Nebula - a reflection nebula surrounding a normal red giant star. Reflection nebulae shine by light reflected from the central star(s). This nebula appears to have been created from the current phase of mass-loss from the central star. Normal gas and dust compose the nebula. The nebula's peculiar but photogenic "bi-polar, bi-conical" shape, however, continue to make it a popular object of study.