Generally, in Astronomy, anything that is not a star (or a planetary body) is a nebula . In this section, we are interested in the nebul æ that are truly clouds of gas and dust. These regions of gas and dust are seen from Earth in a variety of forms, all of which are called nebulae. One of the nearest of these nebulae is the famous Orion Nebula , seen here in a pleasing animation . There are a number of different kinds of nebulae . We find emission nebulae, reflection nebulae and dark nebulae , such as the Horsehead Nebula . . Planetary nebulae are all emission nebulae. In the constellation of Cygnus, there is a very nice nebula known as the Cocoon Nebula . Here we see a stellar nursery where new stars are forming. There is even a nebula named after a continent ! Let’s browse through the Messier Catalog and the Index catalog . And let’s just look through some other nebulae .

Nebulae