EMS- 5.5 Galaxies

EMS- 5.5 Galaxies

By: Ms. Bailey*

​Lesson Objective:

KWBAT describe and classify galaxies into three different types based on their general shape.

KWBAT recognize that the sun is a medium-sized star in a spiral galaxy, the Milky Way and the sun is many thousands times closer to Earth than any other star.​

​TEKs:

8.8(A)  describe components of the universe, including stars, nebulae, and galaxies,  and use models such as the Hertzsprung‐Russell diagram for classification

8.8(B)  recognize that the Sun is a medium-sized star located in a spiral arm of the Milky Way galaxy and that the Sun is many thousands of times closer to Earth than any other star​

​Today You Will Learn:

• The three types of galaxies are spiral, elliptical, and irregular each named from its general shape.

• Spiral galaxies have “arms'' of stars that spiral outward from the center.  The overall shape is round and flat with a dense center.

• Elliptical galaxies are oval in shape.  They may be older than spiral galaxies, because they do not seem to have as many nebulae and dust clouds, and thus cannot form as many new stars.

• Irregular galaxies do not have a regular or defined shape.  They may result from merged galaxies still being reorganized by gravitational forces.

• Our planet, Earth, is located in the Milky Way, which is a spiral galaxy.

• We see the sun as much bigger and brighter because we are closer to it, but many other stars are much bigger and brighter than the sun.

​

​Lesson Vocabulary:

1. Spiral galaxy: a galaxy in which stars and gas clouds form spiral “arms” from a dense center

2. Elliptical galaxy: a galaxy that is oval in shape

3. Irregular galaxy: a galaxy that does not have a regular or defined shape

4. Milky Way: a spiral galaxy in which Earth is located​

​

Multiple Choice

A spiral galaxy is....

• a galaxy in which stars and gas clouds form spiral “arms” from a dense center

• a galaxy with stars and gas

• a galaxy in which stars and gas clouds form different shapes.

Multiple Choice

An elliptical galaxy is....

• a galaxy that is oval in shape

• a galaxy that is circle in shape

• a galaxy that is odd in shape

Multiple Choice

An irregular galaxy is...

• a galaxy that does not have a regular or defined shape

• a galaxy that does have a regular

• a galaxy that does have a defined shape

Multiple Choice

Milky Way galaxy is...

• a spiral galaxy in which Earth is located​

• a circular galaxy in which Earth is located​

• a irregular shaped galaxy in which Earth is located​

​Welcome back, Astronomers!  Yesterday we began exploring just how big the universe is.  We learned that there are billions of galaxies in our universe.  In fact, the Hubble Space Telescope has revealed that there could be an estimated 100 billion galaxies in the universe.  Wow!  Today, we’ll be exploring the different types of galaxies and the Milky Way in more depth.

​Let's See What You Remember.....

Multiple Choice

How does the relative size of planets, stars and nebula compare to a galaxy?

• They are all smaller than a galaxy

• They are all bigger than a galaxy

• A nebula is bigger than a galaxy, but a star and planet are smaller

• A galaxy is bigger than the universe, but a planet, star and nebula are smaller than the universe.

Multiple Choice

One component of the universe consists of a large amount of gas and dust that can reflect light, absorb light or emit light.  When gravity pulls some of the gas and dust together, they form a protostar.  What is this component of the universe?

• nebula

• galaxy

• neutron star

• cosmic dust

​1. Find a NEW partner

2. Grab some colored pencils

3. Make sure it is titled: Types of Galaxies

4. With your partner you will read and draw each type of galaxy:

   Spiral galaxy

   Spiral Bar galaxy

   Elliptical Galaxy

   Irregular Galaxy ​

   ​

​Spiral Galaxies

A spiral galaxy is a rotating disk of stars and dust. In the center is a dense bulge of material. Several spiral arms come out from the center. Spiral galaxies have lots of gas and dust and many young stars.

​Elliptical Galaxies

As you might have guessed, elliptical galaxies are elliptical, or egg-shaped. The smallest elliptical galaxies are as small as some globular clusters. Giant elliptical galaxies can contain over a trillion stars. Elliptical galaxies are reddish to yellowish in color because they contain mostly old stars.

​Irregular and Dwarf Galaxies 

Look at the galaxy pictured to the left . Do you think this is a spiral galaxy or an elliptical galaxy? It is neither one! Galaxies that are not clearly elliptical galaxies or spiral galaxies are called irregular galaxies. Most irregular galaxies were once spiral or elliptical galaxies. They were then deformed either by gravitational attraction to a larger galaxy or by a collision with another galaxy.

 

Dwarf galaxies are small galaxies containing “only” a few million to a few billion stars. Most dwarf galaxies are irregular in shape. However, there are also dwarf elliptical galaxies and dwarf spiral galaxies. Dwarf galaxies are the most common type in the Universe. However, because they are relatively small and dim, we don’t see as many dwarf galaxies as we do their full-sized cousins.

​Proper Positions Please....

Multiple Choice

What are the four different types of galaxies?

• irregular, elliptical, spiral and dwarf

• irregular, spiral, dwarf and massive

• irregular, massive, dwarf and elliptical

Multiple Choice

What type of galaxy is the Milky Way?

• A spiral bar

• An Irregular

• An elliptical

• A dwarf

• A spiral

​Let's Match that Galaxy!!!

Multiple Choice

what type

• spiral

• irregular

• elliptical

Multiple Choice

what type

• elliptical

• spiral

• irregular

• spiral bar

Multiple Choice

what type

• spiral

• irregular

• spiral bar

• elliptical

Multiple Choice

what type

• irregular

• spiral bar

• spiral

• elliptical

Multiple Choice

what type

• spiral bar

• elliptical

• irregular

• spiral

Multiple Choice

what type

• irregular

• elliptical

• spiral

• spiral bar

Open Ended

Based on the chart, why do you think the sun seems bigger and brighter than other stars in the universe?

SS: I believe the sun seems bigger and brighter than other stars because....

​Exit Ticket Time!

Multiple Choice

With the use of the Hubble Space Telescope, scientists recently discovered a giant runaway star.  It is 90 times larger than the sun and is very hot and blue-white in color.  Why does the sun appear to be brighter than this runaway star when viewed from Earth?

• the sun is a different color than the runaway star

• the sun is older than the runaway star

• the sun is closer to Earth than the runaway star

• the sun is made of different elements than the runaway star

Multiple Choice

The Milky Way galaxy is described as a disk of stars orbiting a central point on the disk.  Which of these best explains why people on Earth cannot see the entire shape of the Milky Way?

• Earth is part of this galaxy.

• Many more stars exist outside the galaxy.

• The stars in the center of the galaxy are extremely small.

• The center of the galaxy consists of a dense cluster of stars.

Multiple Choice

Carmen made a model of the galaxy in which Earth’s sun is found.  Which of the following diagrams most likely shows Carmen's model?

​What type of galaxy do we live in? How do you know?