Rough Draft Science report 2

Have you ever wondered how galaxies were made? What type of galaxy the Milky Way is? How many different types of galaxies there are?
Well, after this, you will know. In the universe there are 4 main types of galaxies. Spiral, Elliptical, Irregular and Lenticular.
The first galaxy, and the most popular, is called a Spiral Galaxy. If you see a picture of a galaxy, it's probably a spiral. Our galaxy, the Milky Way, is also a spiral. It is divided into two parts. The Spiral and Barred Spiral. The Spiral has a nucleus with arms of millions of stars that spiral around it. The galaxy is made up of two parts, spheroidal and flat. This is what a spiral galaxy looks like. (Point to poster). The spiral has two parts of it's own. Population 1 and Population 2. Population 1 is a large flat disk that often contains a lot of interstellar matter. That means it has a lot of dust and rubble in it. And population 2 is an open star cluster that is sometimes arranged in spiral patterns or bar structures. The barred spiral galaxy is the second type of spiral galaxies. It is a spiral galaxy with a bar of stars though the middle. It has the same composition but a different appearance.
The second type of galaxies is the elliptical galaxy. (Point to poster). It is probably the most old of the galaxies. It changes in shape from spherical to flattened disks but mostly ellipsoidal shape. It has a smooth structure with bright center and doesn't have spiral arms. They consist of a rotating spheroid of old stars. They do not rotate as a whole. Normally, elliptical galaxies contain very little interstellar matter or sometimes none at all. They mostly consist of Population 2 stars also.
The third type is the irregular galaxy. It has no particular shape and is usually smaller and fainter then other galaxies. Some astronomers think the shape of irregular galaxies are from an explosion in the center of the galaxy.
There are two main types: the mangellanic type and the nonmangellic type.
The mangellic type is emplified by the clouds of Magellan and the nonmangellic type is characterized by a chaotic pattern of dust lanes overlaying a smooth structure.
The last type is the Lenticular. It is not as common or important as the other three but is still a galaxy. These galaxies are pretty much, spiral galaxies without a spiral structure. They are mainly Population two stars. They are smooth disk galaxies, where stellar formation has stopped long ago because the interstellar matter was used up.