Of the 100 billion or more galaxies visible through existing telescopes, most are either spiral or elliptical in shape and about one-fourth are irregular in shape. In addition to their shape, star systems can be further classified using other characteristics, such as the type of material they contain or the angle from which they're viewed. This interactive activity from NOVA invites users to familiarize themselves with spiral galaxies, such as our own Milky Way. The annotated visible light photographs and composites offer opportunities to learn about a galaxy's scale, composition, and rotational pattern.
Learn more here.