What are Galaxies?

Galaxies make up most of the visible matter we can see in the universe. There are over a hundred billion galaxies in the universe. Galaxies are defined as a collection of stars, dust, gas, and planets, and they come in three versions
-Spiral
-Elliptical
-Irregular

                                            

 

  Galaxies come in a variety of shapes and sizes. The largest galaxies contain more than a trillion stars, on average most contain billions of stars. Galaxies are measured in Light Years. The largest galaxy in the universe is 6 million light years across.

 



 Example 1

An Elliptical galaxy is shaped like a sphere, like a ball. The stars in an Elliptical galaxy are often very close together making the center look like one giant star. Galaxies regularly combine, and often form Elliptical galaxies

Example 2

As the name suggests, an Irregular Galaxy has no specific form and can look like anything and have many different characteristics unlike the Elliptical and Spiral galaxies. Many of them are the results of galaxy collision or near misses.


The third type of galaxy, The Spiral, has three main components
-Bulge
-Disk
-Halo
This type of galaxy is what the Milky Way is.

Speaking of the Milky Way, that is the galaxy that earth is located, on one of the "Arms". Our solar system is located 28,000 light years from the center of the Milky Way. The Milky Way is about 100,000 light years across