What Kind of Galaxies are there?
There are three major categories astronomers organize galaxies in. These galaxies vary in size, and amount of stars.
Elliptical galaxies are about one-third of all galaxies known to us currently. Elliptical galaxies are elongated and circular. They have a little amount of gas and dust. Elliptical galaxies typically have older stars and Elliptical galaxies are not actively forming stars anymore.
The largest Elliptical galaxy is the IC 1101. The galaxy has radius of roughly 2 million light years Astronomers theorize that large galaxies form from smaller galaxies merging together.
Spiral Galaxies; We live in the Milky Way which is a spiral. To be specific we live on the Orion arm. Spiral Galaxies appear to be flat, with blue-white disks of stars. Spiral Galaxies are separated into two groups, normal spirals and barred spirals. A barred spiral is when the bar of stars runs through the central bulge. The barred spirals start at the end of the bar. Normal spirals are always creating and are the dominate form of spiral galaxy.
Irregular Galaxies very little dust. Irregular galaxies primarily appear in deep space. Irregular galaxies were abundant in the early universe. So, the irregular galaxies are like looking into the past.