1. Prentice Hall EARTH SCIENCE
Tarbuck Lutgens 

2. STARTER a. 1 year b. 24 hours c. 30 days
Earth’s atmosphere is mostly made of
a. Water vapor b. carbon dioxide c. nitrogen
It takes Earth about _______ to rotate once.
a. 1 year b. 24 hours c. 30 days
Convection currents can occur in
a. solids only b. liquids only
c. gases only d. liquids, gases, and solids
4. True or False: In a convection current, the warmer, less dense fluid rises.
5. Convection currents in Earth’s atmosphere are caused by
a. solar energy b. heat from the Earths interior
c. gravity d. plate movements

3. Key Concepts Vocabulary
How do the terrestrial planets differ from Jovian planets?
How did the solar system form?
Vocabulary
Terrestrial Planet, Jovian Planet, nebula, planetesimal

4. 23.1 The Solar System The Planets: An Overview
 The terrestrial planets are planets that are small and rocky—Mercury, Venus, Earth, and Mars.
 The Jovian planets are the huge gas giants—Jupiter, Saturn, Uranus, and Neptune.
 Pluto does not fit into either the Jovian or the terrestrial category.

5. Orbits of the Planets
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6. 23.1 The Solar System The Planets: An Overview
 Size is the most obvious difference between the terrestrial and Jovian planets.
 Density, chemical makeup, and rate of rotation are other ways in which the two groups of planets differ.

7. Size is the most obvious difference between the terrestrial and the Jovian planets.
The diameter of the largest terrestrial planet, Earth, is only one-quarter the diameter of the smallest Jovian planet, Neptune.
The Jovian planets are often called giants. (also called the outer planets).
The terrestrial planets are closer to the sun and are called the inner planets.
Density, chemical makeup, and rate of rotation are other ways in which the two groups of planets differ.
The densities of the terrestrial planets average about five times the density of water.
The Jovian planets, however, have densities that average only 1.5 times the density of water.
Saturn would float if placed in a large enough water tank.
The different chemical compositions of the planets are largely responsible for these density differences.

8. Planetary Data
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9. 23.1 The Solar System The Planets: An Overview
 The Interiors of the Planets
• The substances that make up the planets are divided into three groups: gases, rocks, and ices.
 The Atmosphere of the Planets
• The Jovian planets have very thick atmospheres of hydrogen, helium, methane, and ammonia.
• By contrast, the terrestrial planets, including Earth, have meager atmospheres at best.

10. The Interior of the Planets
The planets are shown to scale in Figure 2.
The substances that make up the planets are divided into three groups: gases, rocks, and ices.
The gases—hydrogen and helium—are those with melting points near absolute zero (−273°C or 0 kelvin).
The rocks are mainly silicate minerals and metallic iron, which have melting points above 700°C.
The ices include ammonia (NH3), methane (CH4), carbon dioxide (CO2), and water (H2O). They have intermediate melting points. For example, H2O has a melting point of 0°C.

11. The Atmospheres of the Planets
The Jovian planets have very thick atmospheres of hydrogen, helium, methane, and ammonia.
The terrestrial planets, including Earth, have meager atmospheres at best.
A planet’s ability to retain an atmosphere depends on its mass and temperature.
Simply stated, a gas molecule can escape from a planet if it reaches a speed known as the escape velocity.
A comparatively warm body with a small surface gravity, such as our moon, cannot hold even heavy gases.
In contrast, the Jovian planets have much greater surface gravities so, it is more difficult for gases to escape from their gravitational pulls.
The molecular motion of a gas depends upon temperature, at low temperatures even the lightest gases are unlikely to acquire the speed needed to escape.

12. Scale of the Planets Figure 2 The planets are drawn to scale.
Interpreting Diagrams How do the sizes of the terrestrial planets compare with the sizes of the Jovian planets?
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13. NOTEBOOK ASSIGNMENT
Using Figure 1 & 2 on page 644 & 646 answer the following questions:
Which planet is closest to the sun?
The asteroid belt is found between which two planets?
Which planet is the smallest? Largest?
How does the size of the largest planet compare to the size of the sun?

14. 23.1 The Solar System Formation of the Solar System  Nebular Theory
• A nebula is a cloud of gas and/or dust in space.
• According to the nebular theory, the sun and planets formed from a rotating disk of dust and gases.

15. NOTEBOOK ASSIGNMENT
Complete the Reading Strategy.

16. 23.1 The Solar System Formation of the Solar System  Planetesimals
• Planetesimals are small, irregularly shaped bodies formed by colliding matter.

17. Formation of the Universe
Figure 3 Formation of the Universe A According to the nebular theory, the solar system formed from a rotating cloud of dust and gas. B The sun formed at the center of the rotating disk. C Planetesimals collided, eventually gaining enough mass to be planets.
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18. Planetary Composition, Distance from the Sun, and Melting Point
Figure 4 The terrestrial planets formed mainly from silicate minerals and metallic iron that have high melting points. The Jovian planets formed from large quantities of gases and ices.
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19. Classwork
Create a chart to compare and contrast the characteristics of the Terrestrial planets and the Jovian planets.
Complete the Section Assessment ( 1 thru 7) using complete sentences

20. Characteristics
Jovian Planets
Terrestrial Planets
Atmosphere
Distance form one planet to the next
Density
Composition
Rotation Rate
Diameter

21. STARTER: 23.1 Review
What is responsible for the density differences between the terrestrial and Jovian planets?
What is escape velocity?
What is a nebula?
What is the theory for the formation of the solar system?
What is a planetesimal?

22. 23.2 The Terrestrial Planets
Key Concepts
What are the distinguishing characteristics of each terrestrial planet?
Vocabulary
none

23. 23.2 The Terrestrial Planets
Mercury: The Innermost Planet
23.2 The Terrestrial Planets
 Mercury is the innermost and second smallest planet; it is hardly larger than Earth’s moon.
 Surface Features
• Mercury has cratered highlands, much like the moon, and vast smooth terrains that resemble maria.
 Surface Temperatures
• Mercury has the greatest temperature extremes of any planet.

24. Mercury’s Surface
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25. 23.2 The Terrestrial Planets
Venus: The Veiled Planet
23.2 The Terrestrial Planets
 Surface Temperatures
• The surface temperature of Venus reaches 475oC, and its atmosphere is 97 percent carbon dioxide.

26. 23.2 The Terrestrial Planets
Venus: The Veiled Planet
23.2 The Terrestrial Planets
 Venus is similar to Earth in size, density, mass, and location in the solar system. Thus, it has been referred to as “Earth’s twin.”
 Surface Features
• Venus is covered in thick clouds that visible light cannot penetrate.
• About 80 percent of Venus’s surface consists of plains covered by volcanic flow.

27. Venus
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28. 23.2 The Terrestrial Planets
Mars: The Red Planet
23.2 The Terrestrial Planets
 The Martian Atmosphere
• The Martian atmosphere has only 1 percent of the density of Earth’s.
• Although the atmosphere of Mars is very thin, extensive dust storms occur and may cause the color changes observed from Earth.
 Surface Features
• Most Martian surface features are old by Earth standards. The highly cratered southern hemisphere is probably 3.5 billion to 4.5 billion years old.

29. Mars
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30. 23.2 The Terrestrial Planets
Mars: The Red Planet
23.2 The Terrestrial Planets
 Water on Mars
• Some areas of Mars exhibit drainage patterns similar to those created by streams on Earth.
• Images from the Mars Global Surveyor indicate that groundwater has recently migrated to the surface.

31. Water on Mars
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32. Classwork
Compare and contrast Venus and Earth. (You need at least 5 similarities and at least 5 contrasts for each planet.)
True/False Questions. If it is false, make it true.
Mar’s polar ice caps are made mostly of water
There are active volcanoes on Mars.
Mars often has dust storms with hurricane force winds
Mars have canyons that are much larger than Earth’s Grand Canyon.
There is evidence that liquid water once flowed on mars.
Liquid water currently flows on the Martian surface.
Complete the Section Assessment (1 thru 6 ) using complete sentences.
Turn in the above assignment and begin on the sketches.
Make a colored sketch of each terrestrial planet. List each planet’s characteristics next to their sketch.

33. POP QUIZ!!!
The most obvious difference between the terrestrial and Jovian Plant is_______.
Orbital Velocity c. Length of day
Color d. size
2. What is the smallest Planet?
Earth c. Jupiter
Mars d. Pluto
3.Which planet shows evidence of water erosion?
4.Name the terrestrial planets
5.____ is the planet that cannot be classified as neither terrestrial or a Jovian Planet.

34. 23.2 Mini-Quiz
How does Mercury’s period of rotation compare with Earth’s?
What did we learn about Venus from the Magellan spacecraft?
Describe the composition of Venus’s atmosphere?
What did we learn about Mars from the rovers Spirit and Opportunity?
What did we learn from Mars Global Surveyor?

35. Starter
What are your plans for this weekend? Its Valentines!

36. 23.3 The Outer Planets Key Concepts Vocabulary
What characteristics distinguish each outer planet?
Vocabulary
none

37. 23.3 The Outer Planets Jupiter: Giant Among Planets
 Jupiter has a mass that is 2 1/2 times greater than the mass of all the other planets and moons combined.
 Structure of Jupiter
• Jupiter’s hydrogen-helium atmosphere also contains small amounts of methane, ammonia, water, and sulfur compounds.

38. Jupiter and the Great Red Spot
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39. 23.3 The Outer Planets Jupiter: Giant Among Planets  Jupiter’s Moons
• Jupiter’s satellite system, including the 28 moons discovered so far, resembles a miniature solar system.
 Jupiter’s Rings
• Jupiter’s ring system was one of the most unexpected discoveries made by Voyager 1.

40. Jupiter’s Largest Moons
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41. 23.3 The Outer Planets Saturn: The Elegant Planet
 The most prominent feature of Saturn is its system of rings.
 Features of Saturn
• Saturn’s atmosphere is very active, with winds roaring at up to 1500 kilometers per hour.
• Large cyclonic “storms” similar to Jupiter’s Great Red Spot, although smaller, occur in Saturn’s atmosphere.

42. Cassini Approaching Saturn
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43. 23.3 The Outer Planets Saturn: The Elegant Planet  Saturn’s Rings
• Until the discovery that Jupiter, Uranus, and Neptune have ring systems, this phenomenon was thought to be unique to Saturn.
• Most rings fall into one of two categories based on particle density.
 Saturn’s Moons
• Saturn’s satellite system consists of 31 moons.
• Titan is the largest moon, and it is bigger than Mercury.

44. Saturn’s Rings
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45. 23.3 The Outer Planets Uranus: The Sideways Planet
 Instead of being generally perpendicular to the plane of its orbit like the other planets, Uranus’s axis of rotation lies nearly parallel with the plane of its orbit.

46. Uranus
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47. 23.3 The Outer Planets Neptune: The Windy Planet
 Winds exceeding 1000 kilometers per hour encircle Neptune, making it one of the windiest places in the solar system.

48. Neptune
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49. 23.3 The Outer Planets Pluto: Planet X
 Pluto’s orbit is highly eccentric, causing it to occasionally travel inside the orbit of Neptune, where it resided from 1979 through February 1999.

50. Classwork Using Figure 15 on page 656 answer the following questions:
How are rings A and B different from ring C?
What do you think is the cause of this difference?
How are the outer rings different from the inner rings?
How is ring E different from the other rings?
Make a colored sketch of each outer planet. List each planet’s characteristics next to their sketch. Put your sketches in order (Mercury out to Pluto).
Complete the Section Assessment ( 1 thru 6) using complete sentences.

51. 23.3 Mini-Quiz What is the largest planet?
Name the three volcanic members of the solar system family.
How many moons of Saturn have been discovered thus far?
What is unique about Uranus’s axis of rotation?
How long does it take Charon to orbit Pluto?

52. 23.4 Minor Members of the Solar System
Key Concepts
Where are most asteroids located?
What is the structure of a comet?
What is the origin of most meteoroids?
Vocabulary
Asteroid, comet, coma, meteoroid, meteor, meteorite

53. Starter
Complete the vocab for sec. 23.4

54. 23.4 Minor Members of the Solar System
Asteroids: Microplanets
23.4 Minor Members of the Solar System
 An asteroid is a small, rocky body whose diameter can range from a few hundred kilometers to less than a kilometer.
 Most asteroids lie between the orbits of Mars and Jupiter. They have orbital periods of three to six years.

55. Irregular Orbits of Asteroids
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56. 23.4 Minor Members of the Solar System
Comets
23.4 Minor Members of the Solar System
 Comets are small bodies made of rocky and metallic pieces held together by frozen gases. Comets generally revolve about the sun in elongated orbits.

57. 23.4 Minor Members of the Solar System
Comets
23.4 Minor Members of the Solar System
 Coma
• A coma is the fuzzy, gaseous component of a comet’s head.
• A small glowing nucleus with a diameter of only a few kilometers can sometimes be detected within a coma. As comets approach the sun, some, but not all, develop a tail that extends for millions of kilometers.

58. Comet’s Tail Points Away from the Sun
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59. 23.4 Minor Members of the Solar System
Comets
23.4 Minor Members of the Solar System
 Kuiper Belt
• Like the asteroids in the inner solar system, most Kuiper belt comets move in nearly circular orbits that lie roughly in the same plane as the planets.
 Oort Cloud
• Comets with long orbital periods appear to be distributed in all directions from the sun, forming a spherical shell around the solar system called the Oort cloud.

60. 23.4 Minor Members of the Solar System
Comets
23.4 Minor Members of the Solar System
 Halley’s Comet
• The most famous short-period comet is Halley’s comet. Its orbital period is 76 years.

61. 23.4 Minor Members of the Solar System
Meteoroids
23.4 Minor Members of the Solar System
 A meteoroid is a small, solid particle that travels through space.
 A meteor is the luminous phenomenon observed when a meteoroid enters Earth’s atmosphere and burns up, popularly called a shooting star.
 A meteorite is any portion of a meteoroid that reaches Earth’s surface.

62. 23.4 Minor Members of the Solar System
Meteoroids
23.4 Minor Members of the Solar System
 Most meteoroids originate from any one of the following three sources: (1) interplanetary debris that was not gravitationally swept up by the planets during the formation of the solar system, (2) material from the asteroid belt, or (3) the solid remains of comets that once traveled near Earth’s orbit.

63. Major Meteor Showers
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64. Classwork Make a concept map using the vocabulary for the section.
Using Figure 21 on page 661 answer the following questions:
Where are most asteroids found?
Are most of the asteroids near Earth found in the asteroid belt?
What is the shape f all of the asteroid orbits?
Complete the Section Assessment ( 1 thru 6) using complete sentences.

65. 23.4 review starter What is an asteroid?
Where are most asteroids located?
What is the structure of a comet?
In which direction does the tail of a comet point?
What is the origin of most meteoroids?