The Galaxies

The Galaxies

First, a bit of information: A light year is the distance that light travels in one year (roughly six trillion miles). The nearest star to our sun is four light years away.
 

There are four kinds of galaxies: spiral, lenticular, elliptical, and irregular. We live in a spiral galaxy, the Milky Way Galaxy. There are dwarf galaxies that are actually satellites of the Milky Way that are a few hundred light years away. The Milky Way's nearest neighbor, however, is another spiral galaxy called the Andromeda Galaxy. The Andromeda Galaxy is 2 to 3 MILLION light years away.

Each type of galaxy has its own properties:

1. Our galaxy is a spiral galaxy. A spiral galaxy is made up of two basic components; a large flat disc shape that contains a lot of interstellar matter, and young open star clusters. Our sun is one of several hundred billion stars in the spiral Milky Way Galaxy.

2. A lenticular galaxy is a short version of the spiral galaxy in which stellar formation has ceased.

3. An elliptical galaxy is shaped more or less like a football. They have little or no angular momentum and contain little or no interstellar matter.

4. An irregular galaxy is exactly what it sounds like it would be. It is an irregular shape and it doesn't fit well within the scheme of disks and ellipsoids.

Galaxies of all shapes and sizes do have some basic common features. A galaxy contains hundreds or billions of stars like our sun. Most of the time, stars are not loners like our sun. They usually occur in pairs or binaries. Other features that galaxies have in common are:

* Globular star clusters * Planetary nebulae or supernova remnants * Clusters and associations * Super massive dark objects or black holes