Universe Eighth Edition Universe Roger A. Freedman William J. Kaufmann III CHAPTER 12 & 13 Jupiter, Saturn and their Moons CHAPTER 12 & 13 Jupiter, Saturn and their Moons

Online Quiz from Chapter 11 due Wednesday 10/20 Online Quiz from Chapter 12, 13, 14 due Monday 10/25 (relax, Ch. 14 is pretty short). Skip Chapter 15 (“Vagabonds of the Solar System”) Exam II now on Wednesday 10/27 (Ch. 7-14). Half of the lecture period Monday 10/25 will be devoted to comprehensive review like last time. HW and Exam II

Where does the energy for motion in the atmospheres of Jupiter and Saturn come from? A.Heat from the Sun B.Energy from the solar wind C.Tidal interactions with their large moons D.Heat rising from the interior of these planets E.The magnetic fields of the planets Q12.11

Where does the energy for motion in the atmospheres of Jupiter and Saturn come from? A.Heat from the Sun B.Energy from the solar wind C.Tidal interactions with their large moons D.Heat rising from the interior of these planets E.The magnetic fields of the planets A12.11

What is the origin of the magnetic fields of Jupiter and Saturn? A.The thick hydrogen layer is under so much pressure that it becomes a conducting liquid able to generate a magnetic field. B.A large, solid iron core deep inside these planets generates a magnetic field. C.Electric currents flow in large, conducting iron core melted by the tremendous heat. D.Solar winds from the Sun generate the strong magnetic field. E.The solar wind interacts with the hydrogen atmosphere. Q12.9

What is the origin of the magnetic fields of Jupiter and Saturn? A.The thick hydrogen layer is under so much pressure that it becomes a conducting liquid able to generate a magnetic field. B.A large, solid iron core deep inside these planets generates a magnetic field. C.Electric currents flow in large, conducting iron core melted by the tremendous heat. D.Solar winds from the Sun generate the strong magnetic field. E.The solar wind interacts with the hydrogen atmosphere. A12.9

The heating of the Galilean satellites of Jupiter leads to geologically active surfaces. Which one of the following best explains the source of heat? A.As a satellite rotates on its axis, it “flexes” due to the nearby tidal forces of Jupiter. The friction that accompanies the flexing creates heat. B.As the satellite changes its distance from Jupiter in its elliptical orbit, it “flexes” due to the tidal forces of Jupiter. The friction that accompanies the flexing creates heat. C.Jupiter’s intense magnetic field heats up the conducting core of the satellite. D.The heat is left over from the formation of the satellites. E.Interactions with the solar wind cause the heat. Q13.5

The heating of the Galilean satellites of Jupiter leads to geologically active surfaces. Which one of the following best explains the source of heat? A.As a satellite rotates on its axis, it “flexes” due to the nearby tidal forces of Jupiter. The friction that accompanies the flexing creates heat. B.As the satellite changes its distance from Jupiter in its elliptical orbit, it “flexes” due to the tidal forces of Jupiter. The friction that accompanies the flexing creates heat. C.Jupiter’s intense magnetic field heats up the conducting core of the satellite. D.The heat is left over from the formation of the satellites. E.Interactions with the solar wind cause the heat. A13.5

Jupiter’s satellite Ganymede has no atmosphere, whereas Saturn’s satellite Titan has a significant atmosphere. This is because A.Ganymede is much smaller than Titan and thus cannot retain an atmosphere. B.Ganymede is closer to the Sun and warmer than Titan, so any atmosphere would escape into space. C.Ganymede is inactive, whereas Titan is active with volcanoes continually replenishing its atmosphere. D.Titan is close enough to Saturn that gases leak from this planet onto it. Ganymede is too far from Jupiter for this to happen. Q13.13

Jupiter’s satellite Ganymede has no atmosphere, whereas Saturn’s satellite Titan has a significant atmosphere. This is because A.Ganymede is much smaller than Titan and thus cannot retain an atmosphere. B.Ganymede is closer to the Sun and warmer than Titan, so any atmosphere would escape into space. C.Ganymede is inactive, whereas Titan is active with volcanoes continually replenishing its atmosphere. D.Titan is close enough to Saturn that gases leak from this planet onto it. Ganymede is too far from Jupiter for this to happen. A13.13

Key Ideas Composition and Structure: Jupiter and Saturn are both much larger than Earth. Each is composed of 71% hydrogen, 24% helium, and 5% all other elements by mass. Both planets have a higher percentage of heavy elements than does the Sun. Composition and Structure: Jupiter and Saturn are both much larger than Earth. Each is composed of 71% hydrogen, 24% helium, and 5% all other elements by mass. Both planets have a higher percentage of heavy elements than does the Sun. Jupiter probably has a rocky core several times more massive than the Earth. The core is surrounded by a layer of liquid “ices” (water, ammonia, methane, and associated compounds). On top of this is a layer of helium and liquid metallic hydrogen and an outermost layer composed primarily of ordinary hydrogen and helium. All of Jupiter’s visible features are near the top of this outermost layer. Jupiter probably has a rocky core several times more massive than the Earth. The core is surrounded by a layer of liquid “ices” (water, ammonia, methane, and associated compounds). On top of this is a layer of helium and liquid metallic hydrogen and an outermost layer composed primarily of ordinary hydrogen and helium. All of Jupiter’s visible features are near the top of this outermost layer.

Key Ideas Saturn’s internal structure is similar to that of Jupiter, but its core makes up a larger fraction of its volume and its liquid metallic hydrogen mantle is shallower than that of Jupiter. Saturn’s internal structure is similar to that of Jupiter, but its core makes up a larger fraction of its volume and its liquid metallic hydrogen mantle is shallower than that of Jupiter. Jupiter and Saturn both rotate so rapidly that the planets are noticeably flattened. The rotation of both planets’ interiors is revealed by variations in the radio emissions from the planets. Jupiter and Saturn both rotate so rapidly that the planets are noticeably flattened. The rotation of both planets’ interiors is revealed by variations in the radio emissions from the planets. Both Jupiter and Saturn emit more energy than they receive from the Sun. Presumably both planets are still cooling. Both Jupiter and Saturn emit more energy than they receive from the Sun. Presumably both planets are still cooling.

Key Ideas Atmospheres: The visible “surfaces” of Jupiter and Saturn are actually the tops of their clouds. The rapid rotation of the planets twists the clouds into dark belts and light zones that run parallel to the equator. Strong zonal winds run along the belts and zones. The outer layers of both planets’ atmospheres show differential rotation: The equatorial regions rotate slightly faster than the polar regions. For both Jupiter and Saturn, the polar rotation rate is nearly the same as the internal rotation rate. The colored ovals visible in the Jovian atmosphere represent gigantic storms. Some, such as the Great Red Spot, are quite stable and persist for many years. Storms in Saturn’s atmosphere seem to be shorter-lived.

Key Ideas There are presumed to be three cloud layers in the atmospheres of Jupiter and Saturn. The reasons for the distinctive colors of these different layers are not yet known. The cloud layers in Saturn’s atmosphere are spread out over a greater range of altitude than those of Jupiter, giving Saturn a more washed-out appearance. There are presumed to be three cloud layers in the atmospheres of Jupiter and Saturn. The reasons for the distinctive colors of these different layers are not yet known. The cloud layers in Saturn’s atmosphere are spread out over a greater range of altitude than those of Jupiter, giving Saturn a more washed-out appearance. Saturn’s atmosphere contains less helium than Jupiter’s atmosphere. This lower abundance may be the result of helium raining downward into the planet. Helium “rainfall” may also account for Saturn’s surprisingly strong heat output. Saturn’s atmosphere contains less helium than Jupiter’s atmosphere. This lower abundance may be the result of helium raining downward into the planet. Helium “rainfall” may also account for Saturn’s surprisingly strong heat output.

Key Ideas Magnetic Fields and Magnetospheres: Jupiter has a strong magnetic field created by currents in the metallic hydrogen layer. Its huge magnetosphere contains a vast current sheet of electrically charged particles. Charged particles in the densest portions of Jupiter’s magnetosphere emit synchrotron radiation at radio wavelengths. Magnetic Fields and Magnetospheres: Jupiter has a strong magnetic field created by currents in the metallic hydrogen layer. Its huge magnetosphere contains a vast current sheet of electrically charged particles. Charged particles in the densest portions of Jupiter’s magnetosphere emit synchrotron radiation at radio wavelengths. The Jovian magnetosphere encloses a low-density plasma of charged particles. The magnetosphere exists in a delicate balance between pressures from the plasma and from the solar wind. When this balance is disturbed, the size of the magnetosphere fluctuates drastically. The Jovian magnetosphere encloses a low-density plasma of charged particles. The magnetosphere exists in a delicate balance between pressures from the plasma and from the solar wind. When this balance is disturbed, the size of the magnetosphere fluctuates drastically. Saturn’s magnetic field and magnetosphere are much less extensive than Jupiter’s. Saturn’s magnetic field and magnetosphere are much less extensive than Jupiter’s.

Key Ideas Rings: Saturn is circled by a system of thin, broad rings lying in the plane of the planet’s equator. This system is tilted away from the plane of Saturn’s orbit, which causes the rings to be seen at various angles by an Earth-based observer over the course of a Saturnian year. Rings: Saturn is circled by a system of thin, broad rings lying in the plane of the planet’s equator. This system is tilted away from the plane of Saturn’s orbit, which causes the rings to be seen at various angles by an Earth-based observer over the course of a Saturnian year. Structure of the Rings: Saturn has three major, broad rings (A, B, and C) that can be seen from Earth. Other, fainter rings were found by the Voyager spacecraft. Structure of the Rings: Saturn has three major, broad rings (A, B, and C) that can be seen from Earth. Other, fainter rings were found by the Voyager spacecraft.

Key Ideas The principal rings of Saturn are composed of numerous particles of ice and ice-coated rock ranging in size from a few micrometers to about 10 m. Most of the rings exist inside the Roche limit of Saturn, where disruptive tidal forces are stronger than the gravitational forces attracting the ring particles to each other. The principal rings of Saturn are composed of numerous particles of ice and ice-coated rock ranging in size from a few micrometers to about 10 m. Most of the rings exist inside the Roche limit of Saturn, where disruptive tidal forces are stronger than the gravitational forces attracting the ring particles to each other. Each of Saturn’s major rings is composed of a great many narrow ringlets. The faint F ring, which is just outside the A ring, is kept narrow by the gravitational pull of shepherd satellites. Each of Saturn’s major rings is composed of a great many narrow ringlets. The faint F ring, which is just outside the A ring, is kept narrow by the gravitational pull of shepherd satellites. Jupiter’s faint rings are composed of a relatively small amount of small, dark, rocky particles that reflect very little light. Jupiter’s faint rings are composed of a relatively small amount of small, dark, rocky particles that reflect very little light.