1. The Solar System (cont.)
What role did gravity play in the formation of the solar system?
Lesson 2-1

2. The Solar System (cont.)
What objects are in the solar system?
Lesson 2-4

3. The cores of the inner planets are mostly iron.
The four inner planets formed from rocks and heavy elements left behind from the creation of the solar system.
The cores of the inner planets are mostly iron.
Mercury: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington; Venus: NASA; Earth: NASA Goddard Space Flight Center; Mars: NASA/JPL/Malin Space Science Systems
Lesson 2-4

4. The inner planets are the smallest planets.
They have few or no moons, no rings, and they rotate more slowly than the outer planets.
Mercury: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington; Venus: NASA; Earth: NASA Goddard Space Flight Center; Mars: NASA/JPL/Malin Space Science Systems
Lesson 2-4

5. The Solar System (cont.)
At 0.39 AU from the Sun, Mercury is the planet closest to the Sun.
It is the smallest planet, only about one-third the diameter of Earth.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Lesson 2-4

6. The Solar System (cont.)
Temperatures on Mercury can vary by as much as 500°C in a day.
Mercury has almost no atmosphere.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Lesson 2-4

7. The Solar System (cont.)
Venus is 0.72 AU from the Sun.
It is almost the same size and has nearly the same makeup as Earth.
NASA
Lesson 2-4

8. The Solar System (cont.)
One day on Venus is equal to 244 Earth days.
Its heavy atmosphere traps energy from the Sun, making Venus the hottest planet.
NASA
Lesson 2-4

9. The Solar System (cont.)
Earth is 1 AU from the Sun.
The largest and densest of the inner planets, Earth is the only planet where life is known to exist.
NASA Goddard Space Flight Center
Lesson 2-4

10. The Solar System (cont.)
It is also the only planet with large amounts of liquid water on its surface.
Earth’s atmosphere is 78 percent nitrogen and 21 percent oxygen.
NASA Goddard Space Flight Center
Lesson 2-4

11. The Solar System (cont.)
Mars is half the size of Earth and orbits at 1.5 AU from the Sun.
Mars is too cold for liquid water to exist on the surface.
NASA/JPL/Malin Space Science Systems
Lesson 2-4

12. The Solar System (cont.)
Rocks on Mars’s surface contain iron oxides, which give Mars a reddish color.
Mars has some of the largest volcanoes in the solar system, including Olympus Mons.
NASA/JPL/Malin Space Science Systems
Lesson 2-4

13. The Solar System (cont.)
How does Earth differ from other inner planets?
Lesson 2-5

14. The four outermost planets formed farther from the Sun than the inner planets did.
They have more gases and other materials with low boiling points and are often called the gas giants.
Earth: NASA Goddard Space Flight Center; Jupiter: NASA/JPL/USGS; Saturn: NASA and The Hubble Heritage Team (STScI/AURA)Acknowledgment: R.G. French (Wellesley College), J. Cuzzi (NASA/Ames), L. Dones (SwRI), and J.; Uranus, Neptune: NASA/JPL
Lesson 2-5

15. They are larger than the inner planets, they rotate more quickly, and they each have rings.
These planets do not have solid surfaces. They have thick atmospheres of hydrogen and helium.
Earth: NASA Goddard Space Flight Center; Jupiter: NASA/JPL/USGS; Saturn: NASA and The Hubble Heritage Team (STScI/AURA)Acknowledgment: R.G. French (Wellesley College), J. Cuzzi (NASA/Ames), L. Dones (SwRI), and J.; Uranus, Neptune: NASA/JPL
Lesson 2-5

16. The Solar System (cont.)
Jupiter contains more mass than the rest of the planets combined.
Jupiter revolves around the Sun at a distance of 5 AU.
NASA/JPL/USGS
Lesson 2-5

17. The Solar System (cont.)
Jupiter’s clouds swirl with various colors because they contain small amounts of sulfur and phosphorus.
Jupiter has strong weather systems.
NASA/JPL/USGS
Lesson 2-5

18. The Solar System (cont.)
Saturn is the second-largest planet.
At 9.5 AU from the Sun, it is nearly twice as far from the Sun as Jupiter.
NASA and The Hubble Heritage Team (STScI/AURA)Acknowledgment: R.G. French (Wellesley College), J. Cuzzi (NASA/Ames), L. Dones (SwRI), and J.
Lesson 2-5

19. The Solar System (cont.)
Saturn has thousands of thin rings made of billions of pieces of ice ranging in size from pebbles to boulders.
Saturn’s hazy upper atmosphere hides its colorful lower layers.
NASA and The Hubble Heritage Team (STScI/AURA)Acknowledgment: R.G. French (Wellesley College), J. Cuzzi (NASA/Ames), L. Dones (SwRI), and J.
Lesson 2-5

20. The Solar System (cont.)
Uranus orbits the Sun at a distance of nearly 20 AU.
Uranus’s axis sometimes points directly toward the Sun.
Uranus’s blue-green color is caused by methane in its atmosphere.
NASA/JPL
Lesson 2-5

21. The Solar System (cont.)
Neptune orbits the Sun at 30 AU.
Methane in Neptune’s atmosphere causes its blue color.
Neptune has the fastest winds of any planet.
NASA/JPL
Lesson 2-5

22. The Solar System (cont.)
How do the inner and outer planets differ?
Lesson 2-5

23. Which objects orbit the Sun, are nearly spherical in shape, and share their orbital paths with other objects of similar size?
A. asteroids
B. dwarf planets
C. meteoroids
D. moons
Lesson 2 – LR1

24. Which objects are small, rocky, icy objects that orbit the Sun?
A. comets
B. dwarf planets
C. meteors
D. moons
Lesson 2 – LR2

25. Which planets were formed from rocks and heavy elements, including metal?
A. dwarf
B. gas giant
C. inner
D. outer
Lesson 2 – LR3

26. 3. The solar system contains nine planets.
Do you agree or disagree?
3. The solar system contains nine planets.
4. Earth is the only planet that has a moon.
Lesson 2 - Now

27. Lesson 3 Reading Guide - KC
Stars, Galaxies, and the Universe
What are stars?
How does the Sun compare to other stars?
Where is Earth located in the universe?
How is the universe structured?
Lesson 3 Reading Guide - KC