1.1b classification of galaxiesPresentation Transcript
Classification of Galaxies Chapter 16.1b
ACHIEVE Activity – Direct Instruction Conversation – Voice Level 2. Limit to topic. Help – Raise hand until recognized. Integrity – If you go behind in note taking, raise your hand and ask for a “repeat or slow down.” Effort – Sit up eyes on screen, handout, or your notes. Write notes about material presented. Value – Presentation will help you more fully understand Galaxy Classificaton. Efficiency – Glue handouts and notes in notebook for easy access.
Expectation Write down things on your notebook starting from the next available space. Poster will be turned in today.
Classification of Galaxies Irregular Galaxies Elliptical Galaxies Spiral Galaxies
Irregular Galaxies Irregular galaxies have no regular or symmetrical structure. They have regions of elemental hydrogen gas, and many young stars. They have large amounts of dusts from which stars are born.
Spiral Galaxies Spiral galaxies have three main components: a central bulge, disk, and halo
Spiral Galaxies The bulge is a spherical structure found in the center of the galaxy. This feature mostly contains older stars.
Spiral Galaxies The disk is made up of dust, gas, and younger stars. The disk forms arm structures. Our Sun is located in an arm of our galaxy, the Milky Way.
Spiral Galaxies The halo of a galaxy is a loose, spherical structure located around the bulge and some of the disk. The halo contains old clusters of stars, known as globular clusters.
Spiral Galaxies Globular clusters are spherical concentrations of stars typically 100 light years across and containing thousands of stars. Globular clusters 10 billion years old formed when the galaxy was still forming.
Elliptical Galaxies Elliptical galaxies are shaped like an elongated sphere. The light is smooth The surface brightness decreases as you go farther out from the center. Elliptical galaxies have no particular axis of rotation.