Chapter 21 Vocabulary PowerPoint Presentation By: Champa Dulal, Kelsey Dunn, Kamal Dangal, and Lachi Dahal.

Section 4 Star Systems and Galaxies.

Binary Stars Star Systems that have two stars are called double stars or Binary Stars. Some binary stars are called eclipsing binaries.

Are All binary stars part of a star system? Explain why the term “ Some binary stars are called Eclipsing binaries” appropriate? Yes, most stars are members of groups of two or more stars, called star system. It is the appropriate term because ones star in an eclipsing binary sometimes blocks light from the other stars.

Eclipsing Binary A system in which one star periodically blocks the light from another. Figure 16 Eclipsing Binary- Algol is an eclipsing binary star system consisting of a bright star and a dim companion. Each time the dimmer star passes in front of the brighter one, Algol appears less bright.

When does algol appear brighter? Algol appears brighter when the dim companion star passes behind the brighter star.

Open Clusters A loose, disorganized appearance and contains no more than a few thousand stars. They often contain many bright super giants and much gas and dust.

Globular Clusters Large groupings of older stars.

Galaxy A huge group of single stars, star systems, star clusters, dust, and gas bound together by gravity.

What are the main types of galaxies? The main types of galaxies are galaxy, Spiral Galaxy, Elliptical Galaxies, and Irregular Galaxies.

How far away is the center of the galaxy? The center of the galaxy is about 25,000 light-years away, but it is hidden from view by large clouds of dust and gas.

Spiral Galaxies Have a bulge in the middle and arms that spiral outward, like pinwheels. The spiral arms contain many bright young stars as well as gas and dust.

Elliptical Galaxies Galaxy contains billions of stars but have little gas and dust between the stars. Most elliptical galaxies contain only old stars.

Irregular Galaxies A galaxy that doesn’t have a regular shape and that are smaller than other types of galaxies. They generally have many bright, young stars and lots of gas and dust to form new stars.

Quasars A bright object that is 10 billion light-years or more away, making them among the most distant objects in the universe. Look almost like stars. Since Quasi means “something like” in Latin, these objects were given the name quasi-stellar objects, or Quasars.

Universe All of space and everything in it. The universe is enormous, almost beyond imagination.

Scientific Notation A mathematical method of writing numbers using powers of ten. The power of ten to write very large or very small numbers in shorter form.

Other Information.

Our solar system is located in a spiral galaxy called the Milky Way.

How large is the cat’s eye nebula in a light-year? Cat’s eye nebular is about 30,000,000,000,000,000 meters across, or 3x10 to the power of 16 m.

Thanks to Mrs. Keller for helping us with this presentation. We couldn’t do it without your help. We hope you like this we worked really hard on it, Claps to Kelsey Dunn she was a great leader.