Download Galaxy Independent Study Assignment

Galaxy Independent Study Assignment
1. Read the material provided to give you some background about galaxies.
Highlight interesting facts. You will need these facts for another part of the
assignment.
2. Use the information in the article to cut and paste the squares on the last page
of the assignment into the correct columns on the last page of this assignment.
3. Create an art project (drawing, painting, magazine cover, collage…your
choice!) that includes 10 facts about galaxies from the reading. The only
requirements are:
a. Project must include 10 facts
b. Project must be no bigger than 11 x 17
c. Project must be done in ink and with color
Q:1. What is a galaxy?
A galaxy is an enormous collection of a few million to trillions of stars, gas,
and dust held together by gravity. Galaxies can be several thousand to hundreds
of thousands of light-years across.
2. What is the name of our galaxy?
The name of our galaxy is the Milky Way. All of the stars that you see at night
and our Sun belong to the Milky Way. When you go outside in the country on a
dark night and look up, you will see a milky, misty-looking band stretching across
the sky. When you look at this band, you are looking into the densest parts of the
Milky Way: the disk and the bulge.
3. Where is Earth in the Milky Way galaxy?
Our solar system is in a spiral arm called the Orion Arm, and is about twothirds of the way from the center of our galaxy to the edge of the starlight. Earth
is the third planet from the Sun in our solar system of nine planets.
4. What is the closest galaxy like our own? How far away is it?
The closest spiral galaxy is Andromeda, a galaxy much like our own Milky
Way. It is 2.2 million light-years away from us. Andromeda is approaching our
galaxy at a rate of 670,000 miles per hour. Five billion years from now it may
even collide with our Milky Way galaxy.
5. Why do we study galaxies?
By studying other galaxies, astronomers learn more about the Milky Way, the
galaxy that contains our solar system. Answers to such questions as "Do all
galaxies have the same shape?," "Are all galaxies the same size?," "Do they all
have the same number of stars?," and "How and when did galaxies form?" help
astronomers learn about the history of the universe. Galaxies are visible to vast
distances, and trace the structure of the visible universe with their collections of
billions of stars, gas, and dust.
6. What are the parts of a galaxy?
A galaxy contains stars, gas, and dust. In a spiral galaxy like the Milky Way
the stars, gas, and dust are organized into a bulge, a disk containing spiral arms,
and a halo. Elliptical galaxies have a bulge-shape and a halo, but do not have a
disk.
Bulge — A round structure made primarily of old stars, gas, and dust. The bulge
of the Milky Way is roughly 10,000 light-years across. The outer parts of the
bulge are difficult to distinguish from the halo.
Disk — A flattened region that surrounds the bulge in a spiral galaxy. The disk is
shaped like a pancake. The disk of the Milky Way is 100,000 light-years across
and 2000 light-years thick. It contains mostly young stars, gas, and dust, which
are concentrated in spiral arms. Some old stars are also present.
Spiral arms — Curved extensions beginning at the bulge of a spiral galaxy,
giving it a "pinwheel" appearance. Spiral arms contain a lot of gas and dust as
well as young blue stars. Spiral arms are found only in spiral galaxies.
Halo — The halo primarily contains individual old stars and clusters of old stars
(globular clusters). It may be over 130,000 light-years across. The halo also
contains dark matter, which is material that we cannot see but whose
gravitational force can be measured.
Stars, gas, and dust — Stars come in a variety of types. Blue stars, which are
very hot, tend to have shorter lifetimes than red stars, which are cooler. Regions
of galaxies where stars are currently forming are therefore bluer than regions
where there has been no recent star formation. Spiral galaxies seem to have a
lot of gas and dust, while elliptical galaxies have very little gas or dust.
7. How are galaxies classified? What do they look like?
Edwin Hubble classified galaxies into four major types: spiral, barred spiral,
elliptical, and irregular (see also Question 8 and Question 10). Most galaxies are
spirals, barred spirals, or ellipticals.
A spiral galaxy consists of a flattened disk containing spiral (pinwheel-shaped)
arms, a bulge at its center, and a halo. Spiral galaxies have a variety of shapes,
and they are classified according to the size of the bulge and the tightness and
appearance of the arms. The spiral arms, which wrap around the bulge, contain
many young blue stars and lots of gas and dust. Stars in the bulge tend to be
older and redder. Yellow stars like our Sun are found throughout the disk of a
spiral galaxy. These galaxies rotate somewhat like a hurricane or a whirlpool.
(See a side view of a spiral galaxy, below.) A barred spiral galaxy is a spiral
that has a bar-shaped collection of stars running across its center.
An elliptical galaxy does not have a disk or arms; rather, it is characterized by
a smooth, ball-shaped appearance. Ellipticals contain old stars and possess little
gas or dust. They are classified by the shape of the ball, which can range from
round to oval (baseball-shaped to football-shaped). The smallest elliptical
galaxies (called dwarf ellipticals) are probably the most common type of galaxy
in the nearby universe. In contrast to spirals, the stars in ellipticals do not
revolve around the center in an organized way. The stars move on randomlyoriented orbits within the galaxy like a swarm of bees.
An irregular galaxy is neither spiral nor elliptical. Irregular galaxies tend to be
smaller objects without definite shape, and they typically have very hot newer
stars mixed in with lots of gas and dust. These galaxies often have active regions
of star formation. Sometimes their irregular shape is the result of interactions or
collisions between galaxies. Observations such as the Hubble Deep Fields show
that irregular galaxies were more common in the distant (early) universe.
Facts about the Milky Way Galaxy – our home!!
As seen from the Earth, the Milky Way appears as a hazy band of white light in
the sky during the nights. It divides the night sky into two somewhat equal
hemispheres.
The stellar disk of the galaxy is of the size of about 100,000 light-years in
diameter. It is around 1000 light-years in thickness. It consists of as many as 200
to 400 billion stars. It is nearly impossible to estimate the exact age of the Milky
Way. However, the age of the oldest star in the Galaxy is about 13.2 billion years
The Galaxy is composed of a disk of gas, dust and stars that surround a barshaped region. The disk forms four arm structures that take a spiral shape.
Sources- http://amazing-space.stsci.edu and http://www.buzzle.com
Spiral Galaxy
Elliptical Galaxy
Irregular Galaxy
NAME:_________________________
Period: _______
Grading Rubric for Galaxy Independent Study Assignment:
10 points for completed “Galaxy Column” cut and paste activity
Lose 1 point for each incorrect or missing answer
10 points for Galaxy Art Project
1 point for each Galaxy Fact
Minus 1 point if larger than 11” x 17”
Minus 1 point if not done in ink
Minus 1 point if color is not used
TOTAL SCORE
/20
CUT OUT THE SQUARES AND GLUE THEM INTO THE CORRECT COLUMNUSE INFORMATION FROM THE READING!
Contain many young
stars and a lot of
gas and dust
Contain many
newer, very hot
stars with a lot of
gas and dust
Shape is a result of
collisions between
galaxies
The dwarf type of
this galaxy is the
most common in the
universe
Shape is spiral with
a bulge in the center
Smooth, ball shaped
Stars move in the
galaxy like a swarm
of bees
Contain mostly old
stars and only a
little gas or dust
Have no definite
shape
Can be round like a
baseball or oval like
a football
Common in the
distant (early)
universe
Rotate like a
hurricane or
whirlpool