16-3 Notes: The Outer Planets
Except for Pluto, the outer planets are very large planets that are made mostly of gas
or rock. These planets are called gas giants. Gas giants are planets that have deep,
massive gas atmospheres.
Jupiter is the largest planet in our solar system. It is the most massive planet, having
the mass that is twice that of the other eight planets combined. Jupiter is made
mostly of hydrogen. Violent disturbances occur in the planet’s atmosphere. The
Great Red Spot is a storm that is 3 times as large as Earth. Jupiter has rings that are
composed of small dust grains.
Saturn is the second largest planet in the solar system. It is the least dense of all the
planets. Like Jupiter, Saturn is made mostly of hydrogen. It is known for the rings
that orbit its equator. Trillions of particles of water ice, and dust make up the rings.
Uranus is the third largest planet in the solar system. The planet is made mostly of
rock and ices. Hydrogen, helium, and methane make up the planet’s atmosphere.
Unlike most other planets, Uranus is tipped over on its side. Its axis of rotation is
tilted almost 98º and lies almost in the plane of its orbit.
Neptune, a beautiful blue planet, is about the same size as Uranus and is also made
of rock and ices. Its atmosphere contains hydrogen, helium, and methane. Neptune’s
blue color is caused by the absorption of red light by methane in the atmosphere.
The weather on Neptune includes storms and the fastest winds (more than 1,000
km/h) of any planet in the solar system.
Pluto is the most distant planet in the solar system. It is also the smallest planet in
the solar system. Pluto is made mostly of rock and ice. The planet’s atmosphere is
thin and is composed of methane and nitrogen. Pluto’s moon, Charon, is a little
more than half the size of Pluto.
In recent years, scientists have discovered hundreds of objects in our solar system
beyond Neptune’s orbit. This region contains small bodies made mostly of ice. The
region is called the Kuiper belt. Because objects larger than Pluto are found there,
some scientists believe that Pluto should no longer be considered a planet but a
Kuiper belt body. In 2003, what may be the tenth planet in our solar system,
2003UB313, was discovered in the Kuiper belt. It is larger than Pluto.
Unit 7 (Ch. 16) – Earth in the Solar System
Bach
04/08/10
Section 16-3 Review
1. What is a Gas Giant?
A Gas Giant is a large planet in the outer solar system, made mostly of
gases. It has a deep, massive atmosphere, such as Jupiter, Saturn,
Uranus, or Neptune.
2. Compare the size of Jupiter to the size of other planets in the
solar system.
Jupiter is the largest and most massive planet in the solar system. It
has a mass that is twice that of the other eight planets combined.
3. What is the Great Red Spot on Jupiter?
The Great Red Spot is a storm that is 3 times as large as Earth.
4. What are the rings of Saturn made of?
The rings of Saturn are made of trillions of particles of water ice and
dust.
5. What is so unusual about Uranus’s axis of rotation?
Unlike other planets, Uranus has an axis of rotation that is tilted almost
98º and lies almost in the plane of its orbit.
6. Why does Neptune appear bluish in color?
Neptune’s blue color is caused by the absorption of red light by
methane in the atmosphere.
7. Explain how Pluto differs from the other outer planets.
Pluto differs from the other outer planets because it is small and rocky
instead of being made mostly of gases, because it is more distant from
the sun, because it has a thin atmosphere, and because it only has a
single moon.
8. Why do some scientists no longer consider Pluto to be a
planet?
Because some objects have been discovered in the Kuiper belt that
are larger than Pluto.
Unit 7 (Ch. 16) – Earth in the Solar System
Bach
04/08/10
16-3 Notes: The Outer Planets
Except for Pluto, the outer planets are very ________ planets that are made mostly
of gas or rock. These planets are called _____ giants. Gas giants are planets that
have deep, massive gas ___________________.
____________ is the largest planet in our solar system. It is the most __________
planet, having the mass that is twice that of the other eight planets combined. Jupiter
is made mostly of ___________. Violent disturbances occur in the planet’s
_________________. The ________ _____ _______ is a storm that is 3 times as
large as Earth. Jupiter has ________ that are composed of small dust grains.
__________ is the second largest planet in the solar system. It is the least ________
of all the planets. Like Jupiter, Saturn is made mostly of ___________. It is known
for the ________ that orbit its equator. Trillions of particles of water _____, and
_______ make up the rings.
___________ is the third largest planet in the solar system. The planet is made
mostly of _______ and ices. Hydrogen, helium, and ___________ make up the
planet’s atmosphere. Unlike most other planets, Uranus is ___________ over on its
side. Its axis of ____________ is tilted almost 98º and lies almost in the plane of its
________.
___________, a beautiful blue planet, is about the same size as __________ and is
also made of rock and ices. Its atmosphere contains hydrogen, __________, and
methane. Neptune’s blue color is caused by the absorption of red light by
___________ in the atmosphere. The weather on Neptune includes storms and the
fastest ________ (more than 1,000 km/h) of any planet in the solar system.
________ is the most distant planet in the solar system. It is also the ___________
planet in the solar system. Pluto is made mostly of rock and ______. The planet’s
atmosphere is thin and is composed of methane and ___________. Pluto’s moon,
__________, is a little more than half the size of Pluto.
In recent years, scientists have discovered hundreds of objects in our solar system
beyond ___________ orbit. This region contains small bodies made mostly of ____.
The region is called the _________ ______. Because objects larger than Pluto are
found there, some scientists believe that ________ should no longer be considered a
planet but a Kuiper belt body. In 2003, what may be the _______ planet in our solar
system, 2003UB313, was discovered in the Kuiper belt. It is _________ than Pluto.
Unit 7 (Ch. 16) – Earth in the Solar System
Bach
04/08/10
Section 16-3 Review
1. What is a Gas Giant?
2. Compare the size of Jupiter to the size of other planets in the
solar system.
3. What is the Great Red Spot on Jupiter?
4. What are the rings of Saturn made of?
5. What is so unusual about Uranus’s axis of rotation?
6. Why does Neptune appear bluish in color?
7. Explain how Pluto differs from the other outer planets.
8. Why do some scientists no longer consider Pluto to be a
planet?
Unit 7 (Ch. 16) – Earth in the Solar System
Bach
04/08/10