Chapter 8 Moons, Rings, and Plutoids

Chapter 8 Moons, Rings, and Plutoids

Chapter 8Moons, Rings, and Plutoids

Units of Chapter 8 The Galilean Moons of Jupiter The Large Moons of Saturn and Neptune The Medium-Sized Jovian Moons Planetary Rings Beyond Neptune Plutoids and the Kuiper Belt

Question 1 a) increase in density. b) increase in size. c) decrease in cratering. d) decrease in density. e) amount of cratering. As their distance from Jupiter increases, the four Galilean satellites show a consistent

Question 1 a) increase in density. b) increase in size. c) decrease in cratering. d) decrease in density. e) amount of cratering. As their distance from Jupiter increases, the four Galilean satellites show a consistent Like a miniature version of our solar system, Jupiter’s four large moons show a decrease in density as distance increases. Io is most dense of the four; Callisto is least dense.

The Galilean Moons of Jupiter All four Jovian planets have extensive moon systems, and more are continually being discovered. The Galilean moons of Jupiter are those observed by Galileo: Io, Europa, Ganymede, and Callisto.

The Galilean Moons of Jupiter This image shows Jupiter with two of its Galilean moons. Galilean Moons

The Galilean Moons of Jupiter The Galilean moons and their orbits

The Galilean Moons of Jupiter Their interiors

The Galilean Moons of Jupiter • Io is the densest of Jupiter’s moons, and the most geologically active object in the solar system. • It has many active volcanoes, some quite large. • Io can change surface features in a few weeks. • Io has no craters; they fill in too fast – Io has the youngest surface of any solar system object.

Question 3 a) Jupiter’s magnetosphere b) Jupiter’s rapid rotation c) tidal stress from Jupiter and Europa d) radioactive decay from its core e) Io’s large mass and tectonic activity What is thought to cause Io’s volcanism?

Question 3 a) Jupiter’s magnetosphere b) Jupiter’s rapid rotation c) tidal stress from Jupiter and Europa d) radioactive decay from its core e) Io’s large mass and tectonic activity What is thought to cause Io’s volcanism? Io is constantly “squeezed” by its huge neighbor as well as by companion moons, heating its interior.

The Galilean Moons of Jupiter Io Cutaway Io is very close to Jupiter, and also experiences gravitational forces from Europa. The tidal forces are huge, and provide the energy for the volcanoes.

Question 2 a) Europa b) Io c) Amalthea d) Ganymede e) Callisto The surface of which jovian moon most resembles the pack ice of the Arctic Ocean?

Question 2 a) Europa b) Io c) Amalthea d) Ganymede e) Callisto The surface of which jovian moon most resembles the pack ice of the Arctic Ocean? Ice-filled surface cracks indicate an ocean may lie below.

The Galilean Moons of Jupiter Europa has no craters; surface is water ice, possibly with liquid water below. Tidal forces stress and crack ice; water flows, keeping surface relatively flat. Galileo’s View

The Galilean Moons of Jupiter Ganymede is the largest moon in the solar system – larger than Pluto and Mercury. It has a history similar to Earth’s Moon, but with water ice instead of lunar rock. Galileo’s View

The Galilean Moons of Jupiter Callisto is similar to Ganymede; no evidence of plate activity.

The Large Moons of Saturn and Neptune Titan has been known for many years to have an atmosphere thicker and denser than Earth’s; mostly nitrogen and argon. Makes surface impossible to see; the picture at right was taken from only 4000 km away. Saturn Moon

The Large Moons of Saturn and Neptune Infrared image of Titan, showing detail, and possible icy volcano Few craters, consistent with active surface Complex chemical interactions in atmosphere

The Large Moons of Saturn and Neptune The Huygens lander took these images of the surface of Titan. Huygens Probe

The Large Moons of Saturn and Neptune Trace chemicals in Titan’s atmosphere make it chemically complex.

The Large Moons of Saturn and Neptune Triton is in a retrograde orbit; its surface has few craters, indicating an active surface. Nitrogen geysers have been observed on Triton, contributing to the surface features.

The Medium-Sized Jovian Moons Densities of these moons suggest that they are rock and water ice.

The Medium-Sized Jovian Moons Moons of Saturn, in natural color Note the similarities, as well as the large crater on Mimas.

The Medium-Sized Jovian Moons Moons of Uranus and Neptune

The Medium-Sized Jovian Moons Miranda shows evidence of a violent past, although the origin of the surface features is unknown.

Question 8 Which moon in the solar system shows a dense atmosphere? a) our Moon b) Phobos c) Europa d) Titan e) Triton

Question 8 Which moon in the solar system shows a dense atmosphere? a) our Moon b) Phobos c) Europa d) Titan e) Triton The Huygens probe, deployed by the Cassini spacecraft in 2005, showed that Titan’s atmosphere has a complex organic chemistry.

Planetary Rings The ring system of Saturn is large and complex, and easily seen from Earth. The other Jovian planets have ring systems as well.

Question 13 a) Io and Enceladus b) Titan and Europa c) Titan and Triton d) Europa and Miranda e) Phobos and Deimos Which of these moons are most exciting to exobiologists?

Question 13 a) Io and Enceladus b) Titan and Europa c) Titan and Triton d) Europa and Miranda e) Phobos and Deimos Which of these moons are most exciting to exobiologists? Titan shows evidence of channels under its dense atmosphere. Europa has indications of liquid water beneath the ice.

Planetary Rings The rings are not solid; they are composed of small rocky and icy particles.

Planetary Rings Our view of Saturn’s rings changes as the planets move in their orbits.

Question 7 a) They are made of frozen metallic hydrogen. b) They contain glassy beads expelled by volcanoes on Enceladus. c) They contain shiny bits of iron. d) Titan and other moons reflect additional glow onto the rings. e) They are made of relatively new ice. Why are the rings of Saturn so bright?

Question 7 a) They are made of frozen metallic hydrogen. b) They contain glassy beads expelled by volcanoes on Enceladus. c) They contain shiny bits of iron. d) Titan and other moons reflect an additional glow onto the rings. e) They are made of relatively new ice. Why are the rings of Saturn so bright? Saturn’s rings are perhaps only 50 million years old, the result of a small moon coming within the planet’s Roche limit.

Planetary Rings The Roche limit is where the tidal forces of the planet are too strong for a moon to survive; this is where rings are formed.

Question 5 a) distance from a planet, inside of which a moon can be tidally destroyed. b) density that a moon can have and be solid. c) distance from a planet that a moon can experience synchronous rotation. d) mass a moon can have and still be classified as a moon. The Roche limit is defined as the critical

Question 5 a) distance from a planet, inside of which a moon can be tidally destroyed. b) density that a moon can have and be solid. c) distance from a planet that a moon can experience synchronous rotation. d) mass a moon can have and still be classified as a moon. The Roche limit is defined as the critical Saturn’s rings, as well as those of the other jovian planets, lie within its planet’s Roche limit.

Planetary Rings All observed ring systems are within this limit.

Planetary Rings Voyager probes showed Saturn’s rings to be much more complex than originally thought. Earth is shown on the same scale as the rings. Ring Crossing

Planetary Rings “Shepherd” moons define the edges of some of the rings.

Cassini Spacecraft

Question 6 a) satellites in the coma of a comet. b) moons that confine a narrow ring. c) a type of moon that orbits another moon. d) moons that share an orbit of another, larger moon. e) moons that orbit inside a system of rings. Shepherdsatellites are defined as

Question 6 a) satellites in the coma of a comet. b) moons that confine a narrow ring. c) a type of moon that orbits another moon. d) moons that share an orbit of another, larger moon. e) moons that orbit inside a system of rings. Shepherd satellites are defined as

Planetary Rings Jupiter has been found to have a small, thin ring.

Question 4 a) by optical telescopic observers from Earth b) by Voyager I as it passed Jupiter c) by an occultation of a star d) by radar imaging using the Arecibo dish e) with the Hubble SpaceTelescope’s superior resolution How was the ring of Jupiter discovered?

Question 4 a) by optical telescopic observers from Earth b) by Voyager I as it passed Jupiter c) by an occultation of a star d) by radar imaging using the Arecibo dish e) with the Hubble SpaceTelescope’s superior resolution How was the ring of Jupiter discovered? Jupiter’s ring is composed of dark, dusty particles that were first seen when Voyager was past the planet, looking back toward the Sun.

Planetary Rings The rings of Uranus are more complex.

Planetary Rings Two shepherd moons keep the epsilon ring from diffusing.

Chapter 8 Moons, Rings, and Plutoids