A nebula is a cloud of gas and dust in outer space. It is the birthplace of stars and can often be seen as colorful and hazy patches in the night sky. Full definition
Now that we have a scale to work with, let's examine the different type of nebulae in greater detail. (science.howstuffworks.com)
The final stages of life for a star like our Sun result in the star blowing its outer layers out into the surrounding space, forming objects known as planetary nebulae in a wide range of beautiful and striking shapes. (sciencedaily.com)
The patches» signature glow comes from ionized hydrogen, like we see in the Orion Nebula in our own galaxy. (newsweek.com)