Types+of+galaxies

Galaxies can be classified in several ways. The most common is a system developed by Edwin Hubble, which is based on the shapes of galaxies. There is 3 main types of galaxies.


 * Spiral galaxies: The milky way (our galaxy) is a sprial galaxy, they our the most beautiful kind of galaxy.Spirals are flat disks of stars with bright bulges in their centers. Spiral arms wrap around these bulges. Spiral arms probably form as the result of waves that sweep through the galactic disk.
 * Ellipticals: Like spirals, they are named for their shapes: they look like fat, fuzzy footballs. The stars in ellipticals wrap completely around the galaxy's heart in all directions. The largest galaxies in the universe are giant ellipticals. They can contain a trillion stars or more, and span as much as one million light years, about 10 times the diameter of the Milky Way. Like many large spirals, most of them appear to contain "supermassive" black holes at their hearts,they are as much as three billion times as massive as the Sun.
 * Irregulars: These galaxies have no idenifible form, the are neither spirils or ellipticals. Their stars, gasses and dust, spread randomly. These are the smallest galaxies, and has as few as one million stars. They may be like the "building blocks" that came together to form the first large galaxies. Many small irregular galaxies orbit the Milky Way.