1. Read each slide then use the red or some underlined words to complete the organizer.

2. Did it start as a bang!

3. The Expanding Universe
A. The Big Bang Theory:
Idea that all matter began in an infinitely small point and exploded out in all directions

4. Billions of stars, dust, and gas held
Galaxies: _____________________ _____________________________
______________________________
Billions of stars, dust, and gas held
together by gravity

5. Galaxy: Billions of stars, dust and gas held together by gravity
Let’s start out big and work our way down
Universe
Virgo super cluster
Local group
Galaxy: Billions of stars, dust and gas held together by gravity

7. ALL space and everything that is in it.
Universe
ALL space and everything that is in it.

8. Supercluster
Virgo

10. decided to classify them by the way they looked into 3 types
Who knew?
________________ was an astronomer in the 1920s who gathered many pictures of galaxies
noticed they all didn’t look alike
decided to classify them by the way they looked into 3 types
“E” or _____________________
“S” or _____________________
“SB” or ____________________
Spiral
Barred Spiral

11. Galaxies Three types of galaxies:
Galaxies are grouped together in clusters.
The cluster the Milky Way belongs to is called the Local Group.
Three types of galaxies:
Cluster of galaxies

12. Three types of galaxies:
Irregular
Spiral
Elliptical
The Hubble Tuning Fork

13. Where do we live? Earth’s Galaxy—and Others
Galaxies are grouped together in clusters.
The cluster the Milky Way belongs to is called the Local Group.
Cluster of galaxies

14. Spiral Galaxies Arms are made up of stars and dust
Spiral Galaxies: Circular galaxies that have arms curve outward from a central hub.
Arms are made up of stars and dust
Two spiral galaxies!!

15. Illustration/draw and label:

16. halo
disk
bulge
Spiral Galaxy

17. Elliptical Galaxies -Contain mostly older and dimmer stars.
Most common type of galaxy; large three-dimensional football shaped galaxies.
-Contain mostly older and dimmer stars.
Vary in shape from completely round to extremely elongated ovals. Unlike spiral galaxies
No bright nucleus at their center. Elliptical galaxies are represented by the letter E
Divided into seven subgroups according to their shape. These subgroups are labeled E0 to E7. E0 galaxies nearly circular in shape while E7 galaxies are extremely elongated or stretched out.

18. Illustrate / Draw Elliptical

19. Irregular Galaxies
Come in many different shapes and are smaller and less common
Irregular Galaxies - No regular shape, includes nebulas, with no central bulge or spiral arms.

20. Illustrate/ Draw:

21. Earth’s Galaxy
Galaxy: A large group of stars, gas, and dust held together by gravity.
Milky Way: Our galaxy which contains about 200 billion stars and many nebulas
Spiral Galaxies

22. The Milky Way Galaxy
The Milky Way is the galaxy that contains our Solar System which is just one of the several galaxies of the universe.
. This name derives from its appearance as a dim "milky" glowing band arching across the night sky, in which the naked eye cannot distinguish individual stars.
100,000 light years in diameter
Our sun orbits the center of the galaxy once every 240 million years
A barred spiral galaxy
Contains over 200 billion stars
Its where we live!!!!!

23. Solar System
Our star (Sun), the planets, many moons, and other small bodies that ALL travel around the Sun

24. Solar System

25. What do we see in the sky?
The stars move in the sky but not with respect to each other
The planets (or “wanderers”) move differently from stars
They move with respect to the stars
They exhibit strange retrograde motion
What does all this mean?
How can we explain these movements?
What does the universe look like?

26. The Great Debate!
Heraclides (330 B.C.) developed the first Solar System model, beginning of the geocentric versus heliocentric debate

27. Timeline Galileo 1564-1642 Newton 1642-1727 Tycho 1546-1601 Copernicus
Kepler

28. Geocentric (Ptolemaic) System
The theory (in Greek, geo means earth), which maintained that Earth was the center of the universe, usually referring to the system of Claudius Ptolemy.

29. Geocentric (Ptolemaic) System
The accepted model for years
The earth is at the center
The Sun, stars, and planets on their spheres revolve around the earth: explains daily movement

30. Geocentric (Ptolemaic) System cont’…
To account for unusual planetary motion epicycles were introduced
Fit the Greek model of heavenly perfection – spheres are the perfect shape, circular the perfect motion

31. Illustrate/ Draw model:
Select only one to illustrate

32. Heliocentric (Copernican) System
The word "helios" in Greek means "sun." Heliocentric means that the sun is at the center. A heliocentric system is one in which the planets revolve around a fixed sun.
Sun cented is what we believe today

33. Helio- continued
Thus Mercury, Venus, the Earth, Mars, Jupiter and Saturn all revolve around the sun. The moon is the only celestial sphere in this system which revolves around the earth, and, together with it, around the sun.