GALAXY FORMATION
Unit Overview
In the previous unit, you
explored an overview of the history of the universe. In this unit, we will
focus on the formation, evolution, and types of galaxies.
Introductory
Activity – Guided Tour of Galaxies on Worldwide Telescope
Directions: Go to this
website http://www.worldwidetelescope.org/webclient/ and click on “Guided Tours” at the top of the page.
From there, open the “Galaxies” folder and watch the “Universal Beauty” video
clip. In this clip, you will view spectacular images of galaxies and celestial
phenomena in our universe. Feel free to explore other aspects of this website
after you watch this clip.
Galaxy Formation
A galaxy is a collection of
stars, dust and gas held together by gravitational forces. Today, there are
billions of different galaxies in the universe.
Types of Galaxies
Astronomers classify
galaxies according to their size and shape. Common galaxy types include spiral,
elliptical, and irregular galaxies. A spiral galaxy resembles a flattened
disk with spiral arms. An elliptical galaxy has a very smooth
and rounded shape. An irregular galaxy, as the name
implies, does not have a definite structure. Find more details about these
types of galaxies here: https://www.khanacademy.org/partner-content/amnh/the-universe/galaxies/a/what-is-a-galaxy
Our solar system is part
of the Milky Way galaxy, a barred spiral galaxy. It is found on one of the
outer arms of the spiral, known as the Orion arm. In the following image, the
sun’s position is indicated to give you an idea.
Now, explore this site to
further your understanding of galaxy formation and types, as well as the role
of the James Webb Space Telescope in studying galaxies.
http://jwst.nasa.gov/galaxies.html#keyConcepts
Image of the James Webb Space Telescope:
Normal and Active Galaxies
Spiral, elliptical, and irregular galaxies are all
types of normal galaxies. They are typically well developed, and don’t
have areas of extremely high energy. An active galaxy is one in which the
core, or nucleus, of the galaxy is very energetic and bright. The following
link includes a research activity on normal and active galaxies.
Click on the Quizlet icon below to access the
quizlet.com vocabulary flash cards. Review the vocabulary before completing
your assessment.
