23.3 Exploring Outer Planets and Pluto

Which of the following statements is true about the atmospheres of the outer planets?

• They are mostly composed of carbon dioxide.

• They have thick atmospheres with high pressure.

• They lack any form of atmosphere.

• They have thin atmospheres with low pressure.

Answer explanation

The outer planets, such as Jupiter and Saturn, have thick atmospheres primarily composed of hydrogen and helium, resulting in high pressure. This distinguishes them from terrestrial planets, which have thinner atmospheres.

Identify the outer planet with the fastest rotation period.

• Jupiter

• Saturn

• Uranus

• Neptune

Answer explanation

Jupiter has the fastest rotation period of all the outer planets, completing a rotation in just about 10 hours. This rapid spin contributes to its strong magnetic field and distinctive banded appearance.

Evaluate the distance of Neptune from the Sun compared to the other outer planets.

• It is the closest to the Sun.

• It is the second closest to the Sun.

• It is the farthest from the Sun.

• It is closer to the Sun than Uranus.

Answer explanation

Neptune is the farthest planet from the Sun in our solar system, located beyond Uranus. Therefore, the correct choice is that it is the farthest from the Sun.

Which outer planet is known for having a Great Red Spot, a giant storm?

• Saturn

• Uranus

• Neptune

• Jupiter

Answer explanation

Jupiter is known for its Great Red Spot, a massive storm that has been raging for centuries. The other outer planets, Saturn, Uranus, and Neptune, do not have a storm of this magnitude.

Discuss the role of gravity in maintaining the ring systems of the outer planets.

• Gravity pulls the rings into the planet.

• Gravity keeps the rings in orbit around the planet.

• Gravity pushes the rings away from the planet.

• Gravity has no effect on the rings.

Answer explanation

Gravity plays a crucial role in keeping the rings of the outer planets in orbit. It provides the necessary centripetal force to balance the gravitational pull of the planet, preventing the rings from falling into the planet or drifting away.

Evaluate the significance of the discovery of moons around the outer planets.

• It suggests that moons are unique to Earth.

• It indicates that moons are common in the solar system.

• It shows that only gas giants can have moons.

• It proves that moons are formed from the planet's atmosphere.

Answer explanation

The discovery of moons around outer planets indicates that moons are not rare but rather common in the solar system, suggesting that many planets can have their own natural satellites.

Analyze the atmosphere of Jupiter. What is it primarily composed of?

• Oxygen and nitrogen

• Hydrogen and helium

• Carbon dioxide and methane

• Sulfur dioxide and water vapor

Answer explanation

Jupiter's atmosphere is primarily composed of hydrogen and helium, making it similar to the Sun. The other options, such as oxygen, nitrogen, carbon dioxide, and sulfur dioxide, are present in much smaller amounts.

Compare the size of Pluto to the other outer planets.

• Pluto is larger than Neptune.

• Pluto is smaller than all the outer planets.

• Pluto is the same size as Uranus.

• Pluto is larger than Saturn.

Answer explanation

Pluto is classified as a dwarf planet and is significantly smaller than the outer planets: Jupiter, Saturn, Uranus, and Neptune. Therefore, the correct choice is that Pluto is smaller than all the outer planets.

Which outer planet has the most complex and extensive ring system?

• Jupiter

• Saturn

• Uranus

• Neptune

Answer explanation

Saturn is known for its stunning and complex ring system, which is the most extensive among the outer planets. Its rings are made up of ice and rock particles, making them more prominent and intricate than those of Jupiter, Uranus, or Neptune.

Discuss the significance of moons in the outer planets. Which planet has the largest moon in the solar system?

• Jupiter

• Saturn

• Uranus

• Neptune

Answer explanation

Moons play crucial roles in the dynamics and geology of outer planets. Jupiter's moon Ganymede is the largest in the solar system, showcasing the planet's significant gravitational influence and diverse satellite system.