Standard: Galaxies are clusters of billions
of stars, and may have different shapes.
Location: IRC Computer Station
Purpose: To identify galaxies as being
composed of billions of stars, and have different shapes
Instructions: Open up the word document.
On the right side type your
name on the first line,
next line type Science
8, Period ___
and on the 3rd line type
in the date.
Copy the following
worksheet and paste it in the word document.
Save this document
to your folder on the server.
You will be able to access
it in the class later if you do not finish and/or want to print it out.
DO NOT PRINT IN THE IRC
The assignment needs to
be completed and save to my folder at the end of the period.
LAB: Galaxy Quest
FIRST WEB SITE
URL: http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/student1.htm
This is a statement about galaxies: "All ellipticals are galaxies, but not all galaxies are elliptical". After you learn how to classify galaxies, you will be able to explain what this statement means. When scientists see objects in nature that share some features, but not others, they find that grouping, or classifying them is a good idea. First they must decide what scheme or plan they will use to decide to which group something belongs.
Your answers to questions below will come from the online lesson: Classifying Galaxies. Start with the "Student Lesson" and the blinking message: "Start Galaxy exploration here"
FIRST SET OF QUESTIONS
What is a galaxy?1)_____________________________________________________________
In the 1920's, an astronomer named Edwin Hubble was able to gather pictures of many galaxies. He noticed that they were not all alike. He decided to group, or classify them. To group the galaxies in the photographs he studied, he could have used size, color, shape or any other feature that he noticed. Hubble decided to classify galaxies by their shape or form.
Edwin Hubble looked at many galaxy pictures and decided to divide galaxies
into three types according to the way they looked. He used letters to
represent these three types of galaxies.
2)The letter "E" meant _________________ galaxies, 3)"S"
meant
________________________________ galaxies, and 4)"SB" meant ___________________ galaxies.
SECOND SET OF QUESTIONS (click on the link for each type of galaxies
to answer the following questions)
Galaxies had so many shapes that Hubble found that three types were
not enough. He had to further break down these three according to a slight
variation in shape between each type of galaxy in each category.
http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/elipmain.htm
For the "E" or (5)_________________galaxies, he used the amount
of flattening or (6)____________, from E0(
E zero) to E5, to put the galaxies into smaller groups.
Look at the examples of eliptical galaxies by clicking on :"E1", "E2",
"E3", "E4", "E5" on current web page.
http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/sprlmain.htm
For the "S" or (7)____________ galaxies, he used how tightly the
arms were wound around the bright
8)_______________, to further classify
these galaxies as Sa, Sb, or Sc.
Look at the examples of eliptical galaxies by clicking on :"S0, Sa,
Sb, Sc" on current web page.
http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/bsmain.htm
For the "SB" or 9)___________
galaxies, he used the increased openness of
the 10)__________________________to group these
galaxies as SBa, SBb, or SBc.
Look at the examples of eliptical galaxies by clicking on : "SBa",
"SBb", "SBc". on current web page. Click on the starburst ring
link. 11)What telescope was used
to capture a picture of this barred spiral galaxy? _____________
Many galaxies have strange, irregular shapes,
and do not fit neatly into any of these three categories.
12) What is the name of this category
of galaxies? ________________________
THIRD SET OF QUESTIONS
http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/tunfork.htm
Edwin Hubble took all these ideas
and presented them all together in a simple diagram for classifying galaxies.
This diagram is called the Hubble Tuning Fork Diagram. Most galaxies fall
into one of his groups, according to how they look. Copy
and paste the tuning fork
diagram in the space below which he used to identify the shapes,for each
of the types of galaxies below.
(#13) Go over this diagram. It will
appear on your test.
14) You have seen some pictures
of galaxies in this lesson and have looked at how they were classified.
Now it's time for you to classify some galaxy pictures. Are you up
to the challenge? ( your answer should be yes)
Click here. http://cse.ssl.berkeley.edu/SegwayEd/lessons/classifying_galaxies/direct.htm
Read the instruction below the tuning fork
and picture of the galaxy. Write your answer for each galaxy and
it's classification.(continue to add numbers)
1.
2.
3.
SECOND WEB SITE
Hubble Galaxy Classification
http://www.astro.washington.edu/courses/labs/clearinghouse/labs/Hubclass/hubbleclass.html
1. Examine the images of each of the galaxies listed in the table below. When there is more than one galaxy in the image, use the finding chart to identify the galaxy in question. Identify each galaxy's type. (Estimate the subgroup of the spirals, and measure the major and minor axes of the ellipticals so that you can calculate n and find the subclass. Use any scale you like to measure the major and minor axes, but be sure to measure both axes on the same scale. Note: you only need to measure the axes for the elliptical galaxies!)
2. Use the Hubble constant and the
formula given in the Background and Theory section to find the distance
to each galaxy. Convert the distance from Mpc to light years. (1 Mpc =
3.26·106 l.y.) Converting to light years gives the amount of time
the light traveled between leaving the galaxy and arriving at the telescope.
Check to make sure that all of your answers
make sense. For example, check that none of the galaxies' light has been
traveling for more than the age of the Universe.
3. It is often difficult to make astronomical
numbers meaningful. For each of the galaxies, indicate what was happening
in the Earth's history when the light left that galaxy. For reference,
the dinosaurs became extinct about 65 million years ago, Pangaea split
into multiple continents about 200 million years ago, the Earth is about
4.5 billion years old, and the Universe is about 15 billion years old.
Data Table: Hubble
Galaxy Classification
| Galaxy Name | x | y | Type | Velocity
(km/s) |
Distance (Mpc)
1 Mpc = (3.26)·(106) l.y.) |
Light Travel Time (yrs) | Earth-history Reference |
| NGC 1381 | . | 1630 | . | . | . | ||
| NGC 1398 | . | 1299 | . | . | . | ||
| NGC 224 | . | -59 | . | . | . | ||
| NGC 3031 | . | 95 | . | . | . | ||
| NGC 3384 | . | 642 | . | . | . | ||
| NGC 4374 | . | 854 | . | . | . | ||
| NGC 4435 | . | 793 | . | . | . | ||
| NGC 4486 | . | 1180 | . | . | . | ||
| NGC 4565 | . | 1122 | . | . | . | ||
| NGC 4594 | . | 963 | . | . | . | ||
| NGC 4736 | . | 329 | . | . | . | ||
| NGC 5055 | . | 587 | . | . | . | ||
| NGC 5194 | . | 565 | . | . | . | ||
| NGC 5236 | . | 337 | . | . | . | ||
| NGC 7331 | . | 1105 | . | . | . | ||
| 3C273 | . | 43,700 | . | . | . |
1. The velocity of NGC224 is negative.
What does this mean? What are the implications for applying the Hubble
Law to this galaxy?
2. The type of galaxy 3C273 is impossible
to find from these images. Why?
3. Look again at the color image of
ngc5194. What color are the arms? What color is the bulge? What do these
colors tell you about the stellar populations in these regions?
THIRD WEB SITE
GALAXY TOURS
URL:http://school.discovery.com/schooladventures/universe/galaxytour/
Milkyway
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/milkyway.html
1. What type of galaxy is the Milkyway?
2. What makes up the galaxy?
3. Our solar system is 30,000 LY from the nucleus of the Milkyway on the __________ spiral arm.
4. How many light years across is the Milkyway?
5. How is the Milkyway held together?
6. How long will it take for our solar system
to orbit the nucleus of the Milkyway?
Magellanic Clouds
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/magellan.html
1. From what hemisphere can you see the
Small and Large Magellanic Clouds?
2. When, where, will they first be seen and by whom?
3. What are the distances of each of the Magellanic Clouds?
4. Which one has a nebula?
5. Compare the size of the large Magellanic Cloud with the Milkyway.
6. What type of galaxy is the Small and Large Magellanic Clouds?
Andromeda
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/andromeda.html
1. What type of galaxy is the Andromeda?
2. Compare the size to the Milky Way?
3. Why are there several small satellite galaxies to orbit around Andromeda?
4. What other galaxy is Andromeda moving towards?
a. How fast is it moving?
b. After 2 billion years, would will happened to the two galaxies?
5. The Andromeda revolves around a central bulge. What do scientists believe is in the center?
Virgo Cluster
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/virgo.html
1. Where is the Virgo Cluster located?
2. What is contained in the Virgo Cluster?
be specific
3. What is happening to the Local Group of which the Milky Way is a member?
Unusual Galaxies
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/unusual.html
1. What is special about the Siamese Twins?
2. The Sombrero got its name from _
a. Where are the older stars found?
b. Where are the younger stars found?
c. What do scientists think is in the core of the galaxy?
d. If you wanted to see the galaxy through a telescope, which constellation is it near?
3. Polar Ring Galaxy
a. What do polar ring galaxies contain?
b. What is one theory explaining the cause of polar ring galaxies?
Hubble Deep Field
http://school.discoveryeducation.com/schooladventures/universe/galaxytour/hubble.html
1. Looking through the Hubble telescope,
is like looking through a ___________
a. What are you looking at?
b. Looking at these galaxies we are looking back in time. How many years ago?
c. How did the scientist get this type of image?
FOURTH WEB SITE
Galaxy Galore
http://amazing-space.stsci.edu/resources/explorations/
1. Describe each one of the parts of the galaxy after going through the interactives. You may need to go through them again to double check your description.
bulge:
disk:
sprial arms:
halo:
2. Stars gas and dust:After
completing the description, go back to the main page and explore
the other sections. Such as telescopes. http://amazing-space.stsci.edu/resources/explorations/
