2. Chapter Menu Lesson 1: Structure of the Solar System
Lesson 2: The Sun-Earth-Moon System
Lesson 3: The Planets and Their Moons
Lesson 4: Asteroids, Comets, and Meteoroids
Click on a hyperlink to view the corresponding lesson.

3. 11.1 Structure of the Solar System
axis of rotation
period of rotation
period of revolution
ellipse
astronomical unit

4. What is the solar system?
11.1 Structure of the Solar System
What is the solar system?
Our solar system includes planets and dwarf planets, their moons, a star called the Sun, asteroids and comets.
Planets, dwarf planets, asteroids, and comets all orbit the Sun.
Solar Systems

5. The Motion of the Planets
11.1 Structure of the Solar System
The Motion of the Planets
Planets spin like a top spins on the floor.
This spin is known as rotation.
The axis of rotation is an imaginary line through the center of the planet around which the planet rotates.

6. The Motion of the Planets (cont.)
11.1 Structure of the Solar System
The Motion of the Planets (cont.)
Period of rotation—the amount of time it takes to make one complete rotation
Period of revolution—the time it takes a planet to move around the Sun.

7. The Motion of the Planets (cont.)
11.1 Structure of the Solar System
The Motion of the Planets (cont.)

8. Kepler’s Laws of Planetary Motion
11.1 Structure of the Solar System
Kepler’s Laws of Planetary Motion
Kepler studied the motion of planets in the early 1600s.
He proposed three laws that govern the motion of the planets.

9. Kepler’s First Law: Planets Orbits the Sun in Elliptical Paths
11.1 Structure of the Solar System
Kepler’s First Law: Planets Orbits the Sun in Elliptical Paths
Kepler concluded that Mars’ orbit around the Sun is an oval, or ellipse.

10. Kepler’s Second Law: Equal Area in Equal Time
11.1 Structure of the Solar System
Kepler’s Second Law: Equal Area in Equal Time
A line joining any planet to the Sun sweeps out equal areas in equal time.
Planets move faster when they are closer to the Sun than when they are far from the Sun.

11. 11.1 Structure of the Solar System
Kepler’s Third Law: Orbital Period Increases with Distance from the Sun
A planet’s period of revolution increases as its distance from the Sun also increases.

12. 11.1 Structure of the Solar System
The Astronomical Unit
The astronomical unit (AU) is the average distance between the Sun and Earth.
One AU is about 149,6000,000 km.

13. The Astronomical Unit (cont.)
11.1 Structure of the Solar System
The Astronomical Unit (cont.)

14. Gravity and the Solar System
11.1 Structure of the Solar System
Gravity and the Solar System
Recall that all objects that have mass attract each other.
The planets are attracted towards the Sun.

15. The Law of Universal Gravitation
11.1 Structure of the Solar System
The Law of Universal Gravitation
Isaac Newton explained that the force holding the planets in orbit was gravity.

16. Formation of the Solar System
11.1 Structure of the Solar System
Formation of the Solar System
Some scientist think that the solar system was formed from a giant cloud of gas and dust called a nebula.
Dense areas in the cloud attracted more mass and became even more dense.

17. Gravity Forming Stars and Planets
11.1 Structure of the Solar System
Gravity Forming Stars and Planets
The center of the nebula became more dense and the temperature increased.
The Sun formed from nuclear reactions in the center of the nebula.
Material farther away from the center of the nebula formed a disk and began to clump together, eventually becoming planets.

18. 11.1 Structure of the Solar SystemB C D
The period of rotation is the amount of time is takes a planet to ____.
A travel around Mars
B travel one AU
C travel around the Sun
D spin once on its axis
Lesson 1 Review

19. B the average distance between the Earth and its moon
11.1 Structure of the Solar System A B C D
One AU is equal to ____.
A 1 million miles
B the average distance between the Earth and its moon
C the average distance from the Sun to Pluto
D the average distance from the Earth to the Sun
Lesson 1 Review

20. Kepler’s first law of planetary motion states ____.
11.1 Structure of the Solar System A B C D
Kepler’s first law of planetary motion states ____.
A the farther a planet is from the Sun, the longer it takes to complete a revolution
B planets rotate faster when they are closer to the Sun
C planets travel in an elliptical orbit
D planets travel faster when they are closer to the Sun
Lesson 1 Review

21. End of Lesson 1

22. 11.2 The Sun-Earth-Moon System
satellite
lunar phase
eclipse

23. Earth’s Motion Around the Sun
11.2 The Sun-Earth-Moon System
Earth’s Motion Around the Sun
The Moon orbits the Earth, but at the same time, the Earth-Moon system orbits the Sun.

24. Earth’s Orbit The actual path is an ellipse.
11.2 The Sun-Earth-Moon System
Earth’s Orbit
The actual path is an ellipse.
Earth is closest to the Sun in January.
Earth is farthest from the Sun in July.

25. Earth’s Rotation Earth rotates on its axis once every 24 hours.
11.2 The Sun-Earth-Moon System
Earth’s Rotation
Earth rotates on its axis once every 24 hours.
The rotation causes day and night.
Earth’s axis of rotation is 23.5° tilted to the plane of orbit around the Sun.

26. The Moon—Earth’s Satellite
11.2 The Sun-Earth-Moon System
The Moon—Earth’s Satellite
Earth has one moon revolving around it.
A satellite is an object that revolves around a planet.
Moon Exploration

27. 11.2 The Sun-Earth-Moon System
Formation of the Moon
Scientists think that the Moon formed when another large object collided with Earth.
A large amount of matter was ejected into space in the collision.

28. Formation of the Moon (cont.)
11.2 The Sun-Earth-Moon System
Formation of the Moon (cont.)
The material eventually formed the Moon.

29. 11.2 The Sun-Earth-Moon System
The Motion of the Moon
Gravitational force between Earth and the Moon causes the Moon to orbit the Earth.
The Moon rotates on its axis once every 28 days.
Tides

30. The Motion of the Moon (cont.)
11.2 The Sun-Earth-Moon System
The Motion of the Moon (cont.)

31. Phases of the Moon The Moon reflects sunlight.
11.2 The Sun-Earth-Moon System
Phases of the Moon
The Moon reflects sunlight.
As the Moon travels around Earth, the illuminated portion changes.
The different appearances of the Moon are called lunar phases.
How do Earth and the moon interact to cause the moon’s phases?

32. 11.2 The Sun-Earth-Moon System
Eclipses
An eclipse is a total or partial obscuring of one celestial body by another.
There are two types of eclipses:
Lunar
Solar

33. 11.2 The Sun-Earth-Moon System
Lunar Eclipses
A lunar eclipse occurs when a portion of the Moon is shaded from direct sunlight by Earth.
During a lunar eclipse, Earth moves between the Sun and the Moon when the Moon is full.

34. 11.2 The Sun-Earth-Moon System
Solar Eclipses
For a total solar eclipse on Earth, there must be perfect alignment of the Moon and the Sun.
The Moon casts a small shadow on Earth.

35. When is Earth farthest from the Sun? A January B April C July
11.2 The Sun-Earth-Moon System A B C D
When is Earth farthest from the Sun?
A January
B April
C July
D October
Lesson 2 Review

36. What is the phase of the Moon called when it is fully illuminated?
11.2 The Sun-Earth-Moon System A B C D
What is the phase of the Moon called when it is fully illuminated?
A new moon
B full moon
C blue moon
D harvest moon
Lesson 2 Review

37. The light from the moon is produced by ____. A the Moon itself B Earth
11.2 The Sun-Earth-Moon System A B C D
The light from the moon is produced by ____.
A the Moon itself
B Earth
C the Sun
D satellites
Lesson 2 Review

38. End of Lesson 2

39. 11.3 The Planets and Their Moons
inner planet
outer planet

40. 11.3 The Planets and Their Moons
The Inner Planets
The inner planets include Mercury, Venus, Earth, and Mars.
All are rocky in composition.
All are within 1.5 AUs of the Sun.

41. The Inner Planets (cont.)
11.3 The Planets and Their Moons
The Inner Planets (cont.)

42. Mercury Mercury is the closest planet to the Sun.
11.3 The Planets and Their Moons
Mercury
Mercury is the closest planet to the Sun.
Mercury has a highly elliptical orbit and travels faster than any other planet.
Surface temperatures often reach 467°C.

43. Venus Venus is the second planet from the Sun.
11.3 The Planets and Their Moons
Venus
Venus is the second planet from the Sun.
Venus is similar to Earth in size, mass, composition, and distance from the Sun.
Venus is covered by thick clouds of carbon dioxide.
Venus is often the brightest object in the sky except for the Moon.

44. Earth Earth is the third planet from the Sun.
11.3 The Planets and Their Moons
Earth
Earth is the third planet from the Sun.
Earth is the only body in our solar system known to have life on it.
Earth’s atmosphere affects the climate, shields the surface from harmful radiation, and burns up most meteoroids before they strike the surface.

45. Mars Mars is the fourth planet from the Sun.
11.3 The Planets and Their Moons
Mars
Mars is the fourth planet from the Sun.
Mars has two small moons, Phobos and Deimos.
Mars may once have had flowing water.

46. 11.3 The Planets and Their Moons
The Outer Planets
The outer planets include Jupiter, Saturn, Neptune, and Uranus.

47. Jupiter Jupiter is the largest planet in our solar system.
11.3 The Planets and Their Moons
Jupiter
Jupiter is the largest planet in our solar system.
Jupiter’s composition of mostly hydrogen and helium resembles a small star.
Jupiter is the first planet from the Sun to have rings.

48. 11.3 The Planets and Their Moons
Jupiter (cont.)
Jupiter has more than 60 moons; the four largest are Ganymede, Callisto, Io, and Europa.

49. Saturn Saturn is composed mostly of hydrogen and helium.
11.3 The Planets and Their Moons
Saturn
Saturn is composed mostly of hydrogen and helium.
Saturn’s rings are composed mainly of ice and rock.
Saturn has over 30 known moons, the largest is Titan.

50. Uranus Uranus is a blue-green gas planet that rotates on its side.
11.3 The Planets and Their Moons
Uranus
Uranus is a blue-green gas planet that rotates on its side.

51. Uranus (cont.) Uranus has 27 known moons and a series of small rings.
11.3 The Planets and Their Moons
Uranus (cont.)
Uranus has 27 known moons and a series of small rings.
The atmosphere is mainly hydrogen and helium.

52. 11.3 The Planets and Their Moons
Neptune
Neptune was the first planet located by theoretical predictions rather than through ordinary observations.
Neptune has 13 known moons and several rings.
Neptune’s atmosphere is mostly hydrogen, helium, and methane.

53. Dwarf Planets Ceres, Pluto, and Eris are dwarf planets.
11.3 The Planets and Their Moons
Dwarf Planets
Ceres, Pluto, and Eris are dwarf planets.
A dwarf planets differs from a planet because a dwarf planet has not cleared the neighborhood around its orbit.

54. Ceres Ceres was discovered in 1801.
11.3 The Planets and Their Moons
Ceres
It has an average diameter of 940 km.
It is about 2.7 AU from the Sun.
It orbits the Sun in about 4.6 years.
Ceres was discovered in 1801.

55. 11.3 The Planets and Their Moons
Pluto
From the time of Pluto’s discovery in 1930 until 2006, it was known as a planet.
Its average distance to the Sun is 39.2 AU.
Its orbit lasts 248 years.
Its largest moon, Charon, has a diameter of about 1,200 km.
Charon is about half as large as Pluto.

56. 11.3 The Planets and Their Moons
Eris
Astronomers at the California Institute of Technology discovered Eris in 2005.
Its elliptical orbit varies from about 38 AU to 98 AU from the Sun.
Its orbit lasts 557 years.
It has one moon, Dysnomia.
It has a diameter of about 2,400 km.
Eris is slightly larger than Pluto.

57. 11.3 The Planets and Their Moons
Part A Part B Part C Part D

58. Which of the following is NOT one of the inner planets? A Mars
11.3 The Planets and Their Moons A B C D
Which of the following is NOT one of the inner planets?
A Mars
B Jupiter
C Venus
D Earth
Lesson 3 Review

59. Which planet is unique in the position of its axis of rotation?
11.3 The Planets and Their Moons A B C D
Which planet is unique in the position of its axis of rotation?
A Jupiter
B Saturn
C Mercury
D Uranus
Lesson 3 Review

60. The outer planets are composed mostly of ____. A gases B rocks
11.3 The Planets and Their Moons A B C D
The outer planets are composed mostly of ____.
A gases
B rocks
C glaciers
D dust
Lesson 3 Review

61. End of Lesson 3

62. 11.4 Asteroids, Comets and Meteoroids

63. 11.4 Asteroids, Comets, and Meteoroids
Asteroids are rocky objects, smaller than a planet, found between the orbits of Mars and Jupiter.
There are hundreds of thousands of asteroids in the solar system.

64. 11.4 Asteroids, Comets, and Meteoroids
Asteroids (cont.)
Asteroids are thought to be leftover material from the formation of the solar system.

65. Comets A comet is a small, icy body in orbit around the Sun.
11.4 Asteroids, Comets, and Meteoroids
Comets
A comet is a small, icy body in orbit around the Sun.
Some comets have highly elliptical orbits bringing them close to the Sun.
The solid part of a comet is called the nucleus and is made of icy material.
The comet also contains dust, frozen gases, and bits of rock.

66. 11.4 Asteroids, Comets, and Meteoroids
Comets (cont.)
When a comet passes near the Sun, the gases are vaporized forming a tail.

67. 11.4 Asteroids, Comets, and Meteoroids
The Kuiper Belt
Most short-period comets come from a region of Kuiper Belt objects.
The Kuiper Belt is an area of the solar system that extends about 50 AU from the Sun toward the orbit of Neptune.

68. Long-Period Comets and the Oort Cloud
11.4 Asteroids, Comets, and Meteoroids
Long-Period Comets and the Oort Cloud
Some long-period comets have orbital periods in the millions or tens of millions of years.
Some scientists have proposed that these comets originated from the Oort cloud.
The Oort cloud surrounds the solar system.
It might be as far as 100,000 AU from the Sun.

69. 11.4 Asteroids, Comets, and Meteoroids
Meteoroids are solid, interplanetary particles passing through Earth’s atmosphere.
A meteor is the streak of light seen in the sky produced by a meteorite.
A meteorite is the remaining portion of the meteoroid that reaches Earth’s surface.

70. 11.4 Asteroids, Comets, and Meteoroids
Meteoroids (cont.)
Most scientists think that meteoroids came from planets that broke apart during the formation of our solar system.

71. Impact Craters on Earth
11.4 Asteroids, Comets, and Meteoroids
Impact Craters on Earth
Most meteoroids burn up in the atmosphere.
Some large meteors produce impact craters, such as the Barringer Crater in Arizona.

72. A meteoroid that strikes the surface of the Earth is called a(n) ____.
11.4 Asteroids, Comets, and Meteoroids A B C D
A meteoroid that strikes the surface of the Earth is called a(n) ____.
A asteroid
B meteor
C comet
D meteorite
Lesson 4 Review

73. What protects Earth from most meteoroids? A oceans B the atmosphere
11.4 Asteroids, Comets, and Meteoroids A B C D
What protects Earth from most meteoroids?
A oceans
B the atmosphere
C the Moon
D Mars
Lesson 4 Review

74. Where are most of the asteroids in the solar system found?
11.4 Asteroids, Comets, and Meteoroids A B C D
Where are most of the asteroids in the solar system found?
A between Jupiter and Saturn
B Saturn’s rings
C between Mars and Jupiter
D Kuiper Belt
Lesson 4 Review

75. End of Lesson 4

76. Chapter Resources Menu
Chapter Assessment
California Standards Practice
Concepts in Motion
Image Bank
Science Online
Interactive Table
Virtual Lab
BrainPOP
Click on a hyperlink to view the corresponding feature.

77. Which planet has the two moons, Phobos and Deimos? A Mercury B Mars
C Jupiter
D Neptune
Chapter Assessment 1

78. A lunar eclipse occurs when Earth is in the Moon’s shadow. A True B
A lunar eclipse occurs when Earth is in the Moon’s shadow.
A True
B False
Chapter Assessment 2

79. A B C D
What is the phase of the Moon called when no part of it is illuminated?
A full moon
B black moon
C harvest moon
D new moon
Chapter Assessment 3

80. How many planets in our solar system are known to have had life? A 1 B C D
How many planets in our solar system are known to have had life?
A 1
B 2
C 3
D none of the above
Chapter Assessment 4

81. A Planets spin faster as they get closer to the Sun. B C D
Which of the following summarizes Kepler’s third law of planetary motion?
A Planets spin faster as they get closer to the Sun.
B The farther a planet is from the Sun, the longer it takes to complete one orbit.
C Planets travel faster when they are closer to the Sun.
D Planets travel in an elliptical orbit around the Sun.
Chapter Assessment 5

82. Who discovered the 4 largest moons of Jupiter? A Kepler B Newton
SCI 4.e A B C D
Who discovered the 4 largest moons of Jupiter?
A Kepler
B Newton
C Copernicus
D Galileo
CA Standards Practice 1

83. What is the closest outer planet to the Sun? A Mercury B Jupiter
SCI 4.e A B C D
What is the closest outer planet to the Sun?
A Mercury
B Jupiter
C Mars
D Saturn
CA Standards Practice 2

84. Which of the following consists of a frozen ball of rock? A a comet
SCI 4.e A B C D
Which of the following consists of a frozen ball of rock?
A a comet
B an asteroid
C a meteor
D Mars
CA Standards Practice 3

85. What is the third planet from the Sun? A Venus B Mars C Earth D Titan
SCI 4.e A B C D
What is the third planet from the Sun?
A Venus
B Mars
C Earth
D Titan
CA Standards Practice 4

86. What force keeps the Earth orbiting the Sun?
SCI 2.g A B C D
What force keeps the Earth orbiting the Sun?
A the magnetic field of Earth
B the Moon’s gravity
C the Sun’s gravity
D the rotation of Earth on its axis
CA Standards Practice 5

87. Moon Exploration
Concepts in Motion 1

88. Image Bank

89. Image Bank

90. Interactive Table
Planets
Part A Part B Part C Part D

91. End of Resources