There is a lot of stuff floating around out there. Nebulae is a term used to describe dust or gas that can be seen, but it's not all the same.
Sometimes dust is illuminated by nearby stars and appears blue. This is called reflection nebulae. Sometimes, a star's hydrogen emissions cause nearby gas to become excited into a plasma state. This deep red nebulae is called emission nebulae. In some cases, dust "hides" background stars and appears as a dark silhouette and is called dark nebulae. Planetary nebulae is what we see when a star explodes leaving a sort of "ring" shape.
© Barry Etter, Mocksville, NC