Jovian Planets

Jupite
1- The rotation periods for the Jovian planets Jupiter, Saturn, Uranus, and Neptune are
somewhat shorter than that of the Earth, between 10 to 20 hours.
2- The mass of Jupiter compared with that of the Earth is
about 300 times larger.
3- What characteristic features are seen on the visible surface of Jupiter?
light and dark bands parallel to the equator
4- The existence of the Great Red Spot of Jupiter has been known since
the time of Hooke and Cassini in the 1600s.
5- The lifetime of the Great Red Spot of Jupiter appears to be
at least 300 years, from visual records.
6- The rotation period of Jupiter is
relatively short, on the order of 10 hours.
7- One interesting feature of Jupiter’s rotation is the fact that
regions of Jupiter at different latitudes appear to rotate at different rates.
8- The composition of the clouds we see on Jupiter is
similar to the composition of the Earth’s clouds (water droplets and crystals of frozen water) in the
lower levels but very different (ammonia crystals and other chemicals) in the higher levels.

9- How thick are the cloud layers on Jupiter’s visible “surface”?
about 60 km
10- The overall interior structure of the Jovian planets is expected to be
four-layered: a rocky core, a semifluid ice layer, a liquid mantle of hydrogen, and a gaseous hydrogen
and helium atmosphere.
11- The temperature in the core of Jupiter is
hotter than the temperature of the Sun’s surface but cooler than the temperature of the Sun’s core, so
nuclear fusion cannot take place.
12- Jupiter has a magnetic field that is
much more powerful than that of the Earth.
13- The material in the interior of Jupiter that is thought to be responsible for its powerful magnetic
field is
liquid metallic hydrogen.
14- If we could see the full extent of the magnetosphere of Jupiter from the Earth, how big would it
appear in the sky?
16 times larger than the full Moon
15- The general shape of each of the Galilean moons of Jupiter is
almost perfectly spherical.
16- Which characteristic of Jupiter’s satellite Io makes it different from any other known satellite in
the solar system?
Io is volcanically active, with gas plumes and lava flows.

17- The surface of Europa, one of the Galilean moons of Jupiter, appears to be covered with
a smooth layer of ice crossed by many cracks.
18- What features dominate the surface of Ganymede, one of Jupiter’s satellites?
old, dark, highly cratered polygons separated by younger, lighter, grooved terrain
19- The structure of Callisto, the outer Galilean satellite of Jupiter, is thought to be
a mixed ice-rock interior surrounded by a liquid ocean and then a solid icy crust.
20- The material that composes the rings of Jupiter
is continually being ejected from the rings and being replenished from material from the Jovian moons.
21- What kind of ring or rings does Jupiter have?
several thin dark rings made up of very fine dust particles
Saturn
1- Saturn, like Jupiter, is composed primarily of
liquids.
2- Saturn’s atmosphere does not show the same colorful contrast that we see in Jupiter’s
atmosphere because
Saturn has a similar circulation pattern to Jupiter’s, but it is obscured by a thick hazy atmosphere
3- What is the interior structure of Saturn?
rocky core, thick mantle of liquid metallic hydrogen and helium, relatively thin gaseous atmosphere
4- The rings of Saturn are in which plane with respect to the planetary system?
equatorial plane of Saturn

5- The physical structure of Saturn’s rings is
a sequence of many thousands of separate ringlets consisting of ice blocks and ice-coated rock.
6- What is perhaps the most striking feature of the dimensions of the rings of Saturn?
The rings are extremely thin compared to their lateral extent.
7- The rings of Saturn are seen by
reflected and scattered sunlight.
8- The particles in Saturn’s rings
move in circular Keplerian orbits; the inner particles move fastest.
9- What is the Cassini division?
wide, dark gap in Saturn’s rings
10- Why is the F ring much narrower than the main rings?
Two “shepherd” satellites focus the particles into a narrow ring.
11- The main gravitational effect that organizes the particles in the rings of Saturn into specific
narrow orbits is
gravitational perturbations by the large moons orbiting these planets.
12- Saturn’s moon Titan is different from all other moons of the planets because
it possesses a thick atmosphere.
13- The composition of the atmosphere of Titan, a satellite of Saturn, is mostly
nitrogen, methane, and other hydrocarbons.

14- Recent observations suggest that Saturn’s satellite Enceladus possesses all the following
features except one. Which feature does Enceladus probably NOT possess?
molten lava flowing from active volcanoes
15- How would Interplanetary Travel, Inc., advertise a holiday on Titan, one of the satellites of
Saturn?
Exquisite ethane lakes, hydrocarbons beyond your wildest dreams, no shortage of fuel!
16- The surface temperature of Titan, the largest moon of Saturn, is
95 K (–178°C).
17- Which chemical in the atmosphere of Titan (a moon of Saturn) plays the same role that water
plays on Earth by producing “rain,” “snow,” and “ice” at the temperature encountered on Titan?
ethane, C2H6
Uranus and Neptune
1- What are the most abundant gases in the atmosphere of Uranus?
hydrogen and helium, with traces of methane
2- What gives Uranus its blue-green coloration?
absorption of red light by methane gas
3- By what angle is the rotation axis of Uranus tilted from the vertical to its orbit?
98°
4- The expected seasonal changes on Uranus because of its orbital and spin-axis alignments,
compared with those on the Earth, are
very much exaggerated.

5- What is believed to be the basic structure of the interior of Uranus?
rocky core, thick layer of highly compressed liquid water, thick outer layer of liquid hydrogen, thin
gaseous atmosphere
6- The ring system around Uranus was originally discovered by what observation technique?
occultation of light from a star as Uranus (and the rings) passed in front of it
7- The rings of Uranus are
narrow and very dark.
8- Most of the satellites of Uranus orbit the planet in
the plane of the planet’s equator and therefore in a plane almost at right angles to the ecliptic.
9- Miranda, a satellite of Uranus,
appears to have been reassembled from separate parts after being shattered by an impact.
10- How was Neptune discovered?
by a careful application of Newton’s laws to the somewhat irregular motions of Uranus
11- What is the visual appearance of Neptune from space?
blue-green with white, high-altitude clouds and dark storms
12- The Great Dark Spot on Neptune, photographed by Voyager 2 during its flyby of the planet, is
considered to be a
relatively short-lived storm system.
Neptune’s predominantly blue appearance is caused by
absorption of the red end of the spectrum of reflected sunlight by the methane in its atmosphere.

13- One distinct difference between the two otherwise similar planets, Uranus and Neptune, is
the almost featureless visible image of Uranus, compared to distinctly seen storms and clouds on
Neptune.
14- Compared to the Earth, Jupiter, and Saturn, the magnetic fields of Uranus and Neptune
have axes that are tilted a long way from the spin axis of the planets.
15- The magnetic fields of Uranus and Neptune appear to originate in the
liquid water-mineral mixture in the mantles of the planets.
16- The electrically charged particles that produce electric currents and therefore magnetic fields
when they move inside Uranus and Neptune are
molecules such as ammonia (NH3), which become ionized when in solution in water.
17- Does Neptune have rings orbiting the planet?
yes, a system of dark rings of particles coated in chemically modified methane ice
18- Why are the rings of Neptune dark?
The particles are composed of methane ice that has been darkened by radiation damage.
19- Triton, the giant moon of Neptune, differs from all other major moons of the planets because
it orbits in a retrograde direction, opposite to the planet’s rotation.
20- What features characterize the visible surface of Triton, Neptune’s largest moon?
wrinkled surface, frozen lakes, and plumes of nitrogen gas
21- A striking characteristic on Triton, the largest satellite of Neptune, is
plumes of nitrogen gas rising from the icy surface, possibly as a result of radioactive heating.

22- The Roche limit around a planet is defined as the
distance at which a planet creates tides on its moon’s surface high enough to pull its moon apart.