Chapter Menu

1
Chapter Menu
Chapter Introduction Lesson 1 The Structure of
the Solar System Lesson 2 The Inner
Planets Lesson 3 The Outer Planets Lesson 4 Dwarf
Planets and Other Objects Chapter Wrap-Up
NASA/JPL/USGS
2
Chapter Introduction

• What kinds of objects are in the solar system?

3
Chapter Introduction

• What do you think?

Before you begin, decide if you agree or disagree
with each of these statements. As you view this
presentation, see if you change your mind about
any of the statements.
4
Chapter Introduction
Do you agree or disagree?

• 1. Astronomers measure distances between space
  objects using astronomical units.
• 2. Gravitational force keeps planets in orbit
  around the Sun.
• 3. Earth is the only inner planet that has a moon.

5
Chapter Introduction
Do you agree or disagree?

• 4. Venus is the hottest planet in the solar
  system.
• 5. The outer planets also are called the gas
  giants.
• 6. The atmospheres of Saturn and Jupiter are
  mainly water vapor.

6
Chapter Introduction
Do you agree or disagree?

• 7. Asteroids and comets are mainly rock and ice.
• 8. A meteoroid is a meteor that strikes Earth.

7
Lesson 1 Reading Guide - KC
The Structure of the Solar System

• How are the inner planets different from the
  outer planets?
• What is an astronomical unit and why is it used?
• What is the shape of a planets orbit?

8
Lesson 1 Reading Guide - Vocab
The Structure of the Solar System

• asteroid
• comet
• astronomical unit
• period of revolution
• period of rotation

9
Lesson 1-1
What is the solar system?

• Almost all of the specks of light you can see in
  the night sky are stars.
• A few of the tiny lights are part of our solar
  system.
• Stars are much farther away than objects in our
  solar system.

10
Lesson 1-2
Objects in the Solar System

• The largest object in the solar system is the
  Sun, a star.

star Science Use an object in space made of gases
in which nuclear fusion reactions occur that emit
energy Common Use a shape that usually has five
or six points around a common center
11
Lesson 1-2
Objects in the Solar System (cont.)

• Planets orbit the Sun and have nearly spherical
  shapes.
• The mass of a planet must be much larger than the
  total mass of all other objects whose orbits are
  close by.

12
Lesson 1-2
Objects in the Solar System (cont.)

• Eight of the objects in the solar system are
  planets.

• Mercury
• Venus
• Earth
• Mars

• Jupiter
• Saturn
• Uranus
• Neptune

13
Lesson 1-2

• Mercury, Venus, Earth, and Mars are the inner
  planets.
• The inner planets are mostly solid, rocky
  material.

14
Lesson 1-2

• Jupiter, Saturn, Uranus, and Neptune are the
  outer planets.
• The outer planets are mostly ice and gases, such
  as hydrogen and helium.

15
Lesson 1-2
Objects in the Solar System (cont.)
Describe how the inner planets differ from the
outer planets.
16
Lesson 1-2
Objects in the Solar System (cont.)

• A dwarf planet is a spherical object that orbits
  the Sun and is not a moon or another planet.
• Dwarf planets are in regions of the solar system
  where there are many objects orbiting nearby.

17
Lesson 1-2

• Ceres, a dwarf planet, orbits the Sun as planets
  do.

18
Lesson 1-2
Objects in the Solar System (cont.)

• Millions of small, rocky objects called asteroids
  orbit the Sun in the asteroid belt between the
  orbits of Mars and Jupiter.
• Asteroids vary in size and are usually not
  spherical.
• A comet is made of gas, dust, and ice and moves
  around the Sun in an oval-shaped orbit.

19
Lesson 1-2
Objects in the Solar System (cont.)

• Distances between objects in the solar system are
  extremely large.
• Astronomers do not use meters or kilometers to
  describe these distances.
• A more convenient unit is usedthe astronomical
  unit (AU).
• One AU is Earths average distance from the
  Sunabout 150,000,000 km.

20
Lesson 1-2

• It is easier to express very large distances
  using astronomical units rather than kilometers.

21
Lesson 1-2
Objects in the Solar System (cont.)
Define what an astronomical unit is and explain
why it is used.
22
Lesson 1-3
The Motion of the Planets

• The time it takes an object to travel once
  around the Sun is its period of revolution.
• The time it takes an object to complete one
  rotation is its period of rotation.

23
Lesson 1-3
The Motion of the Planets (cont.)

• A planets orbit is an ellipsea stretched-out
  circle.
• Focus points, or foci, determine the shape of the
  ellipse.

24
Lesson 1-2
The Motion of the Planets (cont.)
Describe the shape of a planets orbit.
25
Lesson 1 - VS

• The solar system contains the Sun, the inner
  planets, the outer planets, the dwarf planets,
  asteroids, and comets.

26
Lesson 1 - VS

• An astronomical unit (AU) is a unit of distance
  equal to about 150 million km.

27
Lesson 1 - VS

• The speeds of the planets change as they move
  around the Sun in elliptical orbits.

28
Lesson 1 LR1
What are most of the specks that you can see in
the night sky?
A. asteroids B. comets C. planets D. stars
29
Lesson 1 LR2
What is a spherical object that orbits the Sun
and is not a moon or another planet?
A. asteroid B. astronomical unit C. comet D. dwarf
planet
30
Lesson 1 LR3
Which refers to the time it takes an object to
complete one rotation?
A. astronomical unit B. focus C. period of
revolution D. period of rotation
31
Lesson 1 - Now
Do you agree or disagree?

• 1. Astronomers measure distances between space
  objects using astronomical units.
• 2. Gravitational force keeps planets in orbit
  around the Sun.

32
Lesson 2 Reading Guide - KC
The Inner Planets

• How are the inner planets similar?
• Why is Venus hotter than Mercury?
• What kind of atmospheres do the inner planets
  have?

33
Lesson 2 Reading Guide - Vocab
The Inner Planets

• terrestrial planet
• greenhouse effect

34
Lesson 2-1
Planets Made of Rock

• Earth and the other inner planetsMercury, Venus,
  and Marsare also called the terrestrial planets.
• Like Earth, the other terrestrial planets are
  made of rock and metallic materials and have a
  solid outer layer.

35
Lesson 2-1
Planets Made of Rock (cont.)
terrestrial from Latin terrestris, means earthly
36
Lesson 2-1

• The inner planets are roughly similar in size,
  with Earth being about two and half times larger
  than Mercury.

Mercury NASA/Johns Hopkins University Applied
Physics Laboratory/Carnegie Institution of
WashingtonVenus NASA Earth NASA Goddard Space
Flight CenterMars NASA/JPL/Malin Space Science
Systems
37
Lesson 2-2

• Mercury is the smallest planet and the planet
  closest to the Sun.

38
Lesson 2-2
Mercury

• Mercurys gravity is not strong enough to hold an
  atmosphere.
• Mercurys temperatures are as high as 450C on
  the side toward the Sun and as low as 170 on
  the side away from the Sun.
• Like all inner planets, Mercury has a core made
  of iron and nickel.

39
Lesson 2-2
Mercury (cont.)
How are the inner planets similar?
40
Lesson 2-3

• Venus is the second planet from the Sun and is
  about the same size as Earth.

41
Lesson 2-3
Venus

• The atmosphere of Venus is about 97 percent
  carbon dioxide.
• The pressure of Venuss dense atmosphere is 90
  times greater than that of Earths atmosphere.
• A thick layer of acid clouds covers Venus.

42
Lesson 2-3
Venus (cont.)

• The greenhouse effect occurs when a planets
  atmosphere traps solar energy and causes the
  surface temperature to increase.
• Because of its greenhouse effect, Venus is the
  hottest planet in the solar system, with an
  average temperature of about 460C.

43
Lesson 2-3
Venus (cont.)
Why is Venus hotter than Mercury?
44
Lesson 2-4

• Earth is the third planet from the Sun.

45
Lesson 2-4
Earth

• A mixture of gases, including water vapor, make
  up Earths atmosphere and produce a greenhouse
  effect that raises its surface temperature.
• A protective atmosphere, moderate surface
  temperatures, and the presence of liquid water
  support a variety of life on Earth.

46
Lesson 2-5

• Mars is the fourth planet from the Sun and is
  about half the size of Earth.

47
Lesson 2-5
Mars

• Images of Mars show features that might have been
  made by water, though no evidence of liquid water
  or life has been found.
• The atmosphere of Mars is thin and made of about
  95 percent carbon dioxide.
• Temperatures on Mars range from about 125C at
  the poles to about 20C at the equator during the
  summer.

48
Lesson 2-5
Mars (cont.)
Describe the atmosphere of each inner planet.
49
Lesson 2 - VS

• The terrestrial planets include Mercury, Venus,
  Earth, and Mars.

Mercury NASA/Johns Hopkins University Applied
Physics Laboratory/Carnegie Institution of
WashingtonVenus NASA Earth NASA Goddard Space
Flight CenterMars NASA/JPL/Malin Space Science
Systems
50
Lesson 2 - VS

• The inner planets all are made of rocks and
  minerals, but the characteristics of the planets
  are different. Earth is the only planet with
  water.

NASA Goddard Space Flight Center
51
Lesson 2 - VS

• The greenhouse effect greatly increases the
  surface temperature of Venus.

NASA
52
Lesson 2 LR1
Which planets greenhouse effect makes it the
hottest planet in the solar system?
A. Earth B. Mars C. Mercury D. Venus
53
Lesson 2 LR2
Which is the only planet with large bodies of
liquid water?
A. Earth B. Mars C. Mercury D. Venus
54
Lesson 2 LR3
Which planet is the fourth planet from the Sun
and about half the size of Earth?
A. Mars B. Mercury C. Venus D. none of these
55
Lesson 2 - Now
Do you agree or disagree?
3. Earth is the only inner planet that has a
moon. 4. Venus is the hottest planet in the solar
system.
56
Lesson 3 Reading Guide - KC
The Outer Planets

• How are the outer planets similar?
• What are the outer planets made of?

57
Lesson 3 Reading Guide - Vocab
The Outer Planets

• Galilean moons

58
Lesson 3-1
The Gas Giants

• The outer planets, also known as the gas giants,
  are primarily made of hydrogen and helium.
• The outer planets are extremely massive. They
  apply strong gravitational forces.
• The interiors of the outer planets are mainly
  liquid.
• These gas giants generally have gas and liquid
  layers around a small solid core.

59
Lesson 3-1

• The outer planets are large compared to the inner
  planets. The size of Earth is shown for reference.

Earth NASA Goddard Space Flight CenterJupiter
NASA/JPL/USGSSaturn 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
60
Lesson 3-1
The Gas Giants (cont.)
How are the outer planets similar?
61
Lesson 3-2

• Jupiter is the largest planet in the solar
  system.
• Jupiter has a diameter 11 times larger than the
  diameter of Earth.

62
Lesson 3-2
Jupiter

• Jupiters atmosphere is about 90 percent hydrogen
  and 10 percent helium.
• The planet itself is about 80 percent hydrogen
  and 20 percent helium.
• Jupiter is a ball of gas swirling around a thick
  liquid layer that conceals a solid core.
  Scientists are not certain what makes up the core.

63
Lesson 3-2
Jupiter (cont.)
Describe what makes up each of Jupiters three
distinct layers.
64
Lesson 3-2
Jupiter (cont.)

• Jupiter has at least 63 moons, more than any
  other planet.
• The four largest moons of JupiterIo, Europa,
  Ganymede, and Callistoare known as the Galilean
  moons.
• The Galilean moons are made of rock and ice.

65
Lesson 3-3

• Saturn is the sixth planet from the Sun. It
  rotates rapidly and has horizontal bands of
  clouds.

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Lesson 3-3
Saturn

• Saturn is mostly hydrogen and helium.
• Saturn has an outer gas layer, a thick layer of
  liquid hydrogen, and a solid core.
• Saturn has seven bands of rings, each containing
  thousands of narrower ringlets.

67
Lesson 3-3
Saturn (cont.)

• The ice particles in the rings are possibly from
  a moon that was shattered in a collision with
  another icy object.

Describe what makes up Saturn and its ring system.
68
Lesson 3-3

• Saturn has at least 60 moons. Titan is the only
  moon in the solar system with a dense atmosphere.

Cassini, Rhea, Iapetus, Dione, Tethys
NASA/JPL/Space Science Institute
69
Lesson 3-3
Saturn (cont.)
titan from Green titan, means member of a
mythological race of giants
70
Lesson 3-4

• Uranus is the seventh planet from the Sun, with a
  system of narrow, dark rings and a diameter about
  four times that of Earth.

NASA/ESA and Erich Karkoschka, University of
Arizona
71
Lesson 3-4
Uranus

• Uranus has a deep atmosphere composed mostly of
  hydrogen and helium and a small amount of
  methane.
• Beneath Uranuss atmosphere is a thick, slushy
  layer of water, ammonia, and other materials.
• Uranus has a tilted axis or rotation that might
  have been caused by a collision with an
  Earth-sized object.

72
Lesson 3-4
Uranus (cont.)

• Uranus has at least 27 moons.

Identify the substances that make up the
atmosphere and the thick slushy layer on Uranus.
73
Lesson 3-5

• Like Uranus, Neptunes atmosphere is mostly
  hydrogen and helium, with a trace of methane.

NASA/JPL
74
Lesson 3-5
Neptune

• Neptunes interior is also like Uranuss, made of
  partially frozen water and ammonia with a rock
  and iron core.
• Neptune has at least 13 moons and a faint, dark
  ring system.

75
Lesson 3-5
Neptune (cont.)
How does the atmosphere and interior of Neptune
compare with that of Uranus?
76
Lesson 3 - VS

• All of the outer planets are primarily made of
  materials that are gases on Earth. Colorful
  clouds of gas cover Saturn and Jupiter.

Earth NASA Goddard Space Flight CenterJupiter
NASA/JPL/USGSSaturn 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
77
Lesson 3 - VS

• Jupiter is the largest outer planet. Its four
  largest moons are known as the Galilean moons.

NASA/JPL/USGS
78
Lesson 3 - VS

• Uranus has an unusual tilt, possibly due to a
  collision with a large object.

NASA/ESA and Erich Karkoschka, University of
Arizona
79
Lesson 3 LR1
The outer planets are primarily made of what?
A. oxygen B. methane C. hydrogen and helium
D. carbon dioxide
80
Lesson 3 LR2
What are Jupiters Galilean moons made of?
A. rock and ice B. hydrogen and helium
C. gas D. carbon dioxide
81
Lesson 3 LR3
Which planet is the seventh from the Sun and has
a system of narrow, dark rings?
A. Jupiter B. Neptune C. Saturn D. Uranus
82
Lesson 3 - Now
Do you agree or disagree?
5. The outer planets also are called the gas
giants. 6. The atmospheres of Saturn and Jupiter
are mainly water vapor.
83
Lesson 4 Reading Guide - KC
Dwarf Planets and Other Objects

• What is a dwarf planet?
• What are the characteristics of comets and
  asteroids?
• How does an impact crater form?

84
Lesson 4 Reading Guide - Vocab
Dwarf Planets and Other Objects

• meteoroid
• meteor
• meteorite
• impact crater

85
Lesson 4-1
Dwarf Planets

• According to the International Astronomical Union
  (IAU), a dwarf planet is an object that orbits a
  star and has enough mass and gravity to pull
  itself into a spherical shape.

86
Lesson 4-1
Dwarf Planets (cont.)

• Unlike a planet, a dwarf planet has objects
  similar in mass orbiting nearby or crossing its
  orbital path.
• Ceres is the smallest dwarf planet with a
  diameter of about 950 km.
• Pluto is so far from the Sun that it takes about
  248 years to complete one orbit.
• Eris is the largest dwarf planet.

87
Lesson 4-1

• All of the dwarf planets are smaller than Earths
  moon.

Pluto Dr. R. Albrecht, ESA/ESO Space Telescope
European Coordinating Facility NASACeres NASA,
ESA, and J. Parker (Southwest Research
Institute)Eris NASA, ESA, and M. Brown
(California Institute of Technology)
88
Lesson 4-1
Dwarf Planets (cont.)
Describe the characteristics of a dwarf planet.
89
Lesson 4-2

• Most asteroids orbit the Sun in the asteroid belt
  between the orbits of Mars and Jupiter.

Asteroid NASA/JPL/JHUAPLIda NASA/JPL/USGSVesta
Ben Zellner (Georgia Southern University),
Peter Thomas (Cornell University), NASA/ESAEros
NASA/Goddard Space Flight Center Scientific
Visualization Studio
90
Lesson 4-2
Asteroids

• Asteroids are chunks of rock and ice that never
  clumped together to form a planet.
• Some astronomers think the strength of Jupiters
  gravitational field might have caused the chunks
  to collide so violently that they broke apart
  instead of sticking together.

91
Lesson 4-2
Asteroids (cont.)
Where do the orbits of most asteroids occur?
92
Lesson 4-3

• Comets are mixtures of rock, ice, and dust.

Comet Roger Ressmeyer/Getty ImagesWild 2
NASA/JPL-Caltech
93
Lesson 4-3
Comets

• The particles in a comet are loosely held
  together by the gravitational attractions among
  the particles.
• Comets orbit the Sun in stretched out elliptical
  orbits.
• The solid, inner part of a comet is its nucleus.
• As a comet moves closer to the Sun, it heats up
  and can develop a bright tail.

94
Lesson 4-3
Comets (cont.)
Describe the characteristics of a comet.
95
Lesson 4-4
Meteoroids

• A meteoroid is a small rocky particle that moves
  through space.
• A meteor is a streak of light in Earths
  atmosphere made by a glowing meteoroid.

96
Lesson 4-4
Meteoroids (cont.)

• A meteorite is a meteoroid that strikes a planet
  or a moon.
• An impact crater is a round depression formed on
  the surface of a planet, moon, or other space
  object by the impact of a meteorite.

97
Lesson 4-4
Meteoroids (cont.)
What causes an impact crater to form?
98
Lesson 4 - VS

• An asteroid, such as Ida, is a chunk of rock and
  ice that orbits the Sun.

NASA/JPL/USGS
99
Lesson 4 - VS

• Comets, which are mixture of rock, ice, and dust,
  orbit the Sun. A comets tail is caused by its
  interaction with the Sun.

Roger Ressmeyer/Getty Images

• When a large meteorite strikes a planet or moon,
  it often makes an impact crater.

100
Lesson 4 LR1
Which term refers to chunks of rock and ice that
never clumped together to form a planet?
A. meteoroid B. meteor C. comet D. asteroid
101
Lesson 4 LR2
Which is a round depression formed on the surface
of a planet, moon, or other space object by the
impact of a meteorite?
A. coma B. impact crater C. meteor D. meteoroid
102
Lesson 4 LR3
Which objects orbit the Sun in stretched out
elliptical orbits?
A. asteroids B. comets C. meteoroids D. meteors
103
Lesson 4 - Now
Do you agree or disagree?
7. Asteroids and comets are mainly rock and
ice. 8. A meteoroid is a meteor that strikes
Earth.
104
Chapter Review Menu
Key Concept Summary Interactive Concept
Map Chapter Review Standardized Test Practice
105
The BIG Idea

• The solar system contains planets, dwarf
  planets, comets, asteroids, and other small solar
  system bodies.

106
Key Concepts 1
Lesson 1 The Structure of the Solar System

• The inner planets are made mainly of solid
  materials. The outer planets, which are larger
  than the inner planets, have thick gas and liquid
  layers covering a small solid core.
• Astronomers measure vast distances in space in
  astronomical units an astronomical unit is
  about 150 million km.
• The speed of each planet changes as it moves
  along its elliptical orbit around the Sun.

107
Key Concepts 2
Lesson 2 The Inner Planets

• The inner planetsMercury, Venus, Earth, and
  Marsare made of rock and metallic materials.
• The greenhouse effect makes Venus the hottest
  planet.
• Mercury has no atmosphere. The atmospheres of
  Venus and Mars are almost entirely carbon
  dioxide. Earths atmosphere is a mixture of gases
  and a small amount of water vapor.

108
Key Concepts 3
Lesson 3 The Outer Planets

• The outer planetsJupiter, Saturn, Uranus, and
  Neptuneare primarily made of hydrogen and
  helium.
• Jupiter and Saturn have thick cloud layers, but
  are mainly liquid hydrogen. Saturns rings are
  largely particles of ice. Uranus and Neptune
  have thick atmospheres of hydrogen and helium.

109
Key Concepts 4
Lesson 4 Dwarf Planets and Other Objects

• A dwarf planet is an object that orbits a star,
  has enough mass to pull itself into a spherical
  shape, and has objects similar in mass orbiting
  nearby.
• An asteroid is a small rocky object that orbits
  the Sun. Comets are made of rock, ice, and dust
  and orbit the Sun in highly elliptical paths.
• An impact crater is formed by the impact of a
  meteorite.

Roger Ressmeyer/Getty Images
110
Chapter Review MC1
What term refers to the small, rocky objects that
orbit the Sun between the orbits of Mars and
Jupiter?
A. asteroids B. comets C. dwarf planets
D. planets
111
Chapter Review MC2
How many objects in the solar system are
classified as planets?
A. 8 B. 10 C. 12 D. 14
112
Chapter Review MC3
The greenhouse effect occurs when a planets
atmosphere traps solar energy and causes which of
these?
A. decrease in surface temperature B. decreased
number of plant species C. increase in surface
temperature D. increased number of plant species
113
Chapter Review MC4
Which planet has a tilted axis that might have
been caused by a collision with an Earth-sized
object?
A. Jupiter B. Neptune C. Saturn D. Uranus
114
Chapter Review MC5
Which term refers to a small rocky particle that
moves through space?
A. asteroid B. meteor C. meteorite D. meteoroid
115
Chapter Review STP1
Which term refers to an object made of gas, dust,
and ice that moves around the Sun in an
oval-shaped orbit?
A. asteroid B. comet C. dwarf planet D. star
116
Chapter Review STP2
What is a term used to describe the four planets
closest to the Sun?
A. dwarf planets B. gas giants C. inner
planets D. outer planets
117
Chapter Review STP3
Which planet is fourth from the Sun and about
half the size of Earth?
A. Mars B. Mercury C. Neptune D. Venus
118
Chapter Review STP4
How many moons does Saturn have?
A. 1 B. at least 60 C. less than 4 D. at most 27
119
Chapter Review STP5
Which of these describes a meteoroid that strikes
a planet or a moon?
A. meteorite B. meteor C. impact
crater D. asteroid