Dwarf Galaxies

There are 3 main types of galaxies in our universe; elliptical, spiral, and irregular.  Sometime galaxies form with considerably less stars than usually. Astronomers call these galaxies dwarf galaxies.  They can still fall into the 3 categories but they are much smaller.

An elliptical galaxy is a galaxy that has an ellipsoidal shape.  Most elliptical galaxies are composed of low-mass older stars. Here is a picture of an elliptical galaxy:

A spiral galaxy is a galaxy that has spiral arms, a disk, and a bulge.  The spiral arms contain young stars, while the disk and bulge contain the older stars in the galaxy. An example of a spiral galaxy is the Milky Way and here is a photo:

 An irregular galaxy is just a galaxy that cannot be classified as either spiral or elliptical. Here is a photo of one: