Essica was looking at the sky one night using a telescope. While looking at the night Sky, she was able to find the Andromeda Galaxy. She asked her older sister what are the differences and similarities between the 3 types of Galaxies? What should her older sister answer? Please remember to support your answer with examples for each. Atleast 3 complete sentences.

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Today, the basis for how we classify galaxies is still rooted in morphology, or how the galaxies appear. Astronomers group galaxies by shape, and although there are many different types of galaxies, most fall into one of three categories: spiral, elliptical or irregular.

Explanation:

Barred Spiral Galaxy

Barred spiral galaxies share the same features and functions as regular spiral galaxies, but they also have a bar of bright stars that lie along the center of the bulge, and extend into the disk. The bright bulge has very little activity here and contains mostly older, red stars. The bar and arms have lots of activity.including star formation.

While the classification for barred spirals is the same as it is for regular spiral galaxies, the bar must be considered as well. Short bars correlate to tighter galaxies and will be included in the designation SBa. SBb have longer bars and SBc are the longest. Most astronomers now agree that the Milky Way is a barred spiral galaxy.

Elliptical Galaxy

Elliptical galaxies can be recognized by their elongated spherical shape and their lack of nucleus or bulge at the center. Although there is no nucleus, the galaxy is still brighter in the center and becomes less bright toward the outer edges of the galaxy. Stars, gases and other materials are spread throughout the elliptical galaxy. An elliptical galaxy can be nearly round or long and cigar shaped.

It is believed that a great deal of the mass in an elliptical galaxy is due to the presence of a central black hole. These galaxies have very little activity and contain mostly old stars of low mass, because there aren’t the gasses and dust needed to form new stars.

Irregular Galaxy

Irregular galaxies are composed of gasses, dust, stars, nebulous formations, neutron stars, black holes and other elements common to all galaxies. Irregular galaxies are named so because they have no definite shape, but like all galaxies, they are in constant motion, moving outward and away from the center of our universe. Irregular galaxies are divided into two classifications: Im and IO.

Im galaxies occur most often among irregular galaxies and may show a trace of the spiral galaxy arms. IO galaxies are completely random and can be called chaotic in nature. The Magellanic clouds that border our own Milky Way Galaxy are examples of Im galaxies. Approximately 20% of our galaxies are classified as irregular

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