1. Earth Science Bellringer
Get out your “When We Left Earth” 10 facts.

2. II. Galaxies, Solar System & Planets

3. A. Galaxy
1. A galaxy is a group of stars, dust, and gases held together by gravity.

4. Elliptical- round to oval Irregular- no general shape
2. Types of Galaxies
Spiral- spiral arms
Elliptical- round to oval
Irregular- no general shape

5. Classify these 3 galaxies.
Elliptical A. B.
Spiral
Irregular C.
Classify these 3 galaxies.

6. B. Solar System Solar System composition Solar system formation
-planets, moons, star, asteroids, comets
-Nebula Hypothesis
Cloud of dust formed spinning disk (solar nebula)
Center gas formed sun
Outer gas form small bodies (planetesimals)

7. C. Observing the Solar System
Geocentric- earth at center
Ptolemy- Greek astronomer developed the idea

8. 2. Heliocentric- sun at center
Copernicus- Polish astronomer developed idea Galileo supported idea

9. D. Planets 1. Inner Planets
- Terrestrial or Earth like Planets: made of solid material

10. We’re just little guys…
How Big is it!?!?!

11. The Size of the Solar System
Check out the graphs and see if you can sort the planets into two groups.

14. Other characteristics
Don’t Forget:
We are not worried about Pluto, it’s not a planet

15. Mercury One rotation takes 59 days. One year is 88 days.
It has no moon or rings.
Mercury is the closest planet to the sun.
It looks a lot like our moon.
Click here to
learn about Mercury.

16. a. Mercury- smallest planet, not much larger than the moon.

17. Venus One rotation takes 243 days. One year is 224.7 days.
It has no moon or rings.
Venus is the second planet from the sun.
It is as dry as a desert and hotter than an oven..
Click here to
learn more about
Venus.

18. b. Venus- “Earth’s Twin”, atmosphere is full of clouds & gives a yellow color.

19. Earth One rotation takes 24 hours. One year is 365 1/4 days.
It has 1 moon and no rings.
It is the third planet from the sun.
Earth is mostly covered with water.

20. c. Earth- only planet with known life

21. MARS One rotation takes 24.5 hours. One year is 687 days.
It has 2 moons and no rings.
It is the fourth planet from the sun and the last of the inner planets.
Mars looks red because of rusty iron in its soil and red dust in its air.

22. d. Mars- “red planet”, red color due to iron-rich rocks, large canyons suggest that water was present in the past.

23. D. Planets 1. Inner Planets 2. Outer Planets
- Terrestrial or Earth like Planets: made of solid material
-Jovian or Jupiter like planets: made of gases

24. Jupiter One rotation takes 9.8 hours. One year is 12 earth years.
It has at least 16 moons and 2 rings.
It is the fifth planet from the sun and the first gas planet.
It has a great red spot of swirling gas.

25. a. Jupiter- largest planet, contains the “Great Red Spot” (huge storm)

26. Maybe ice on Europa?

27. Saturn One rotation takes 10.7 hours. One year is 29.5 Earth years.
It has at least 17 moons and many rings.
Saturn is the sixth planet from the sun and the second gas planet.
Saturn’s rings are made of ice, rock, and dust.

28. b. Saturn- rings made of small ice particles

29. Uranus One rotation takes 17 hours. One year is 84 earth years.
It has at least 15 moons and 10 rings.
Uranus is the seventh planet from the sun and the third gas planet.
Uranus seems to rotate on its side.

30. c. Uranus- rotates on its side

31. Neptune One rotation takes 16 hours. One year is 165 earth years.
It has 8 moons and 4 rings.
It is the eighth planet from the sun and the last gas planet.
Neptune is blue-green.
Neptune

32. d. Neptune- fastest winds in the solar system (1,200 mph)

33. Pluto Is it a planet? One rotation takes 6 days.
One year is 248 earth years.
It has 1 moon and no rings.
It is the ninth, and last planet from the sun, but every 248 years Neptune orbits farther than Pluto.
Charon is Pluto’s moon.

34. E. Pluto Why Pluto is NOT a planet: Pluto & its moon Charon
a. A planet must be:
1.) in orbit around the Sun,
2.) large enough to have become round due to the force of its own gravity
3.) dominates the neighborhood around its orbit.
Pluto & its moon Charon

36. Planet Topic Questions
Red Textbook:
Pg all
Pg all
Pg (test your knowledge)
Do on separate sheet of paper
You have 20 Minutes