1. Spiral - Elliptical - Irregular
DO NOW QUESTION
What is an example of each type of galaxy?
Spiral - Elliptical - Irregular
Milky Way
Andromeda
M87
Large
Magnellanic
Cloud
Add examples to your Princeton Notes!

2. Elliptical
Spiral
Irregular

3. Galaxy Large groups of stars, dust, and gas
Come in a variety of sizes and shapes
Can have more than a trillion stars
Can estimate how many sun-sized stars the galaxy may have by studying the size and brightness of the galaxy

4. Spiral Galaxy Bulge at the center and spiral arms
Spiral arms are made up of gas, dust, and new stars

5. Milky Way Galaxy
Spiral Galaxy

6. 5. What is an elliptical galaxy?
1/3 of all galaxies
Described as a “massive blob” of stars
Generally looks like a sphere
Has a very bright center
Very little gas and dust
Contains mostly old stars

7. 6. What is an irregular galaxy?
Irregular shaped galaxy
“cloud-like”
ADD TO NOTES:
¼ of all galaxies
Contains large amount of gas and dust
A lot of star formation occurs within

8. 10. What are quasars? Among the most distant objects in space
“Star-like” sources of light
Among the most powerful energy sources in the Universe
May be caused by massive black holes in the cores of distant galaxies

9. Because they are so far away, they are found using radio waves
Fun Fact:
Because they are so far away, they are found using radio waves
Quasars

10. How the Universe Works: Galaxies

11. Nebula Large clouds of gas and dust Some glow
Some absorb light and hide stars
Some reflect starlight
Some are regions where new stars form
Spiral galaxies usually contain nebulas
Elliptical galaxies contain very few nebulas

12. EX: Crab Nebula In the Taurus constellation Not visible to unaided eye
At center is the Crab pulsar

13. Globular Cluster Groups of older stars Looks like a ball
Up to 1 million stars
Located in a spherical halo that surround spiral galaxies
Also commonly located near giant elliptical galaxies

14. EX: Omega Centauri Cluster
Largest and brightest globular cluster in Milky Way Galaxy
EX: Omega Centauri Cluster
Located in Centaurus constellation
10,000,000 stars
- 12 billion years old
Visible to unaided eye

15. Open Clusters Groups of closely grouped stars
Usually located along the spiral disk of a galaxy
Newly formed open clusters have many bright blue stars
Few hundred to a few thousand stars

16. EX: The Wild Duck Cluster (M11)
Located in Scutum constellation
2,900 stars
220 million years old
Not visible with unaided eye