Editor: Andrew Grenbemer
Table of Contents
Overview of Jovian Planets Page 1
Overview of Jupiter Page 2
Overview of Saturn Page 3
Overview of Neptune Page 4
Overview of Uranus Page 5
Pluto Page 6
Discovery of Jupiter Page 7
Discovery of Neptune and Uranus Page 8
Discovery of Pluto Page 9
Surfaces of the Jovian Planets Page 10
Weather on the Jovian Planets Page 11
Recent Images of the Jovian Planets Page 12
Galilean Moons of Jupiter Page 13
Moons of Jovian Planets Page 14
Planetary Rings Page 15
Rings of Saturn Page 16
Gas Giants vs Ice Giants Page 17
Maelyn Leis
Unlike how it sounds, ice giants aren’t necessarily made up of ice--they’re
just comprised of substances heavier than
hydrogen and helium, and though those
substances might have been ice at the planet’s
formation, they now exist in a variety of
stages (solid, liquid, and gas).
Uranus and Neptune are the only ice giants in the solar system. Uranus
has more hydrogen and helium, but is less
massive than Neptune, while Neptune is very
dense and has a hot core and active
atmosphere.
Both gas and ice giants are different from
terrestrial planets, which are rocky.
Jupiter and Saturn are gas giants. Uranus and
Neptune are also sometimes considered gas
giants, but they were redefined as ice giants
to show the difference in their structure.
Jupiter and Saturn are much larger planets, as
well. Gas giants aren’t made of solid material; instead, their atmospheres are a
thick gas comprised of hydrogen and helium.
The planet’s gases gradually thin to nothing
the farther from the planet.
The term “gas giant” was actually coined by a science fiction writer and
isn’t a totally accurate name, since the planets
are made up of liquid and gas, and because of
the temperature, the two are hardly
distinguishable.
While gas giants have metallic hydrogen
cores, ice giants do not. The hydrogen cores
are “metallic” because the pressure makes the hydrogen a conductor.
Neptune
Uranus
Mars is a terrestrial planet
Becca Bright
Information Source: http://en.wikipedia.org/wiki/Main_Page
The Jovian Moons
The Jovian planets are best known for being not only the largest planets in our Solar
System, but also known for being the planets with the most moons. Being either large
or small, volcanic or frozen, there is much more to these moons than meets the eye.
There are 67 confirmed Jovian moons, 53 officially named Saturnian moons (9 more
have confirmed orbits, but have not yet been officially named, otherwise the total
would be 62), 27 known Uranian moons, while there are 14 known Neptunian moons.
Io: The driest known object in our Solar System, Io (a moon of Ju-
piter) is named after a priestess of Hera in Greek mythology, who
was also one of Zeus/Jupiter’s lovers. Nicknamed the “cosmic piz-
za,” Io is the most geologically active body in our Solar System with
over 400 active volcanoes. Io is also possibly the most colorful ob-
ject in our Solar System, painted by the volcanic plumes and lava
flows, coloring the surface subtle shades of yellow, red, white,
black, and green.
Europa: Icy and small, Europa is named after the mortal Eu-
ropa, a Phoenician woman of high lineage in Greek mytholo-
gy, and one of Zeus/Jupiter’s lovers. A water ocean is
thought to exist beneath the thick ice of Europa, which
could serve as a home for extraterrestrial life. In fact, as of
September 2014, NASA reported finding evidence confirm-
ing earlier reports of plate tectonics in the thick casing of
ice, the first sign of such geological activity on another world
other than Earth. A mission to Europa is planned to launch
in 2022.
Ganymede: The largest moon both of Jupiter and our Solar System,
Ganymede is named after the cupbearer of the gods in Greek my-
thology, and is one of Zeus/Jupiter’s many lovers. Ganymede is
also the only moon known to possess a magnetosphere. Its diame-
ter is 2% larger than that of Titan, the second largest moon in the
Solar System.
Callisto: If Callisto were closer, it could be mistaken for our
own moon! Callisto is named after a nymph from Greek
mythology, and a lover of Zeus/Jupiter. Callisto looks very
similar to our moon, and is tidally locked to its revolution
around Jupiter. The surface is possibly the oldest and most
heavily cratered in our Solar System. The presence of an
ocean within Callisto leaves the possibility that it could
harbor life, though the conditions are thought to be less
favorable than on nearby Europa.
Becca Bright
Information Source: http://en.wikipedia.org/wiki/Main_Page
Titan: The largest moon of Saturn and the second largest moon
in the Solar System. Titan is named after the powerful deities of
Greek mythology known as Titans. Titan is also the only known
natural satellite to have a dense atmosphere and have clear evi-
dence of stable bodies of surface liquid. The climate (which in-
cludes wind and rain) creates surface features similar to those of
Earth’s. Dunes, rivers, lakes, seas, and deltas can form from Ti-
tan’s wind and rain. On June 23, 2014, NASA found strong evi-
dence that the nitrogen in Titan’s atmosphere came from materi-
als in the Oort cloud, which is associated with comets, and not
from the materials that formed Saturn.
Enceladus: A very bright Saturnian moon, named after the
giant Enceladus of Greek mythology. Though it may be small
(only 500 km in diameter), it reflects almost all the sunlight
that strikes it, making it one of Saturn’s brightest moons. En-
celadus orbits in the densest part of Saturn’s diffuse E-ring.
The surface consists of a wide range of features, from old and
heavily cratered, to young and tectonically deformed terrain.
The discovery of cryovolcanoes (ice volcano, volcanoes that
erupt volatiles such as water, ammonia, or methane instead of
molten rock) on its surface revealed that Enceladus has re-
leased most of the materials that make up Saturn’s E-ring.
Tethys: Named after an aquatic sea goddess of Greek mythology.
Tethys is heavily cratered and vary bright, the second brightest
moon of Saturn after Enceladus. Though the least dense of all
the major moons in the Solar System, Tethys is full of unique sur-
face features. The most prominent feature on Tethys is an im-
pact crater-Odysseus-which is about 200 km in diameter.
Miranda: An extreme terrain gives Miranda a rough surface.
Miranda is named after a character from Shakespeare’s The
Tempest. Miranda possesses the most extreme and varied
topography, the highest cliff (Verona Rupes) being 20 km high,
the tallest in the Solar System. It is also known to be one of
the smallest objects in the Solar System to be spherical under
its own gravity. Unfortunately, the origin and evolution of its
geology is not fully understood.
Umbriel: Not much is known about Umbriel, a Uranian moon
named after the character from Alexander Pope’s The Rape of
the Lock. The surface is the darkest among the Uranian moons
and appears to be shaped primarily by impacts. However, the
presence of canyons suggests early endogenic processes, and the
moon may have undergone and early endogenically driven resur-
facing event that obliterated its outer surface. Its most promi-
nent feature is a ring of bright material on the floor of Wunda
crater.
Becca Bright
Information Source: http://en.wikipedia.org/wiki/Main_Page
Titania: Uranus’s largest moon, Titania is named after the
queen of the fairies in Shakespeare’s A Midsummer Night’s
Dream. Relatively dark and slightly red in color, Titania ap-
pears to have been shaped by both impacts and endogenic
processes. Not very much is known about Titania, but infra-
red spectroscopy conducted from 2001 to 2005 revealed the
presence of water ice as well as frozen carbon dioxide on the
surface. This suggests that the moon may possess a tenuous
carbon dioxide atmosphere.
Oberon: Uranus’s outermost major moon, Oberon is named after
the mythical king of the fairies who appears as a character in
Shakespeare's A Midsummer Night’s Dream. Among the most
heavily cratered of the outer moons, the largest impact craters
reach up to 210 km in diameter. The surface has been primarily
shaped by asteroid and comet impacts. It appears to be similar in
color to Titania’s surface.
Triton: The largest moon of Neptune, Triton is named after
the son of Poseidon/Neptune. The orbit of Triton is retro-
grade, the only large moon in the Solar System with such an
orbit. This, along with its composition (mostly frozen nitro-
gen, a mostly water ice crust, an icy mantle, and a substan-
tial core of rock and metal), has led to the hypothesis that
Triton may not have formed with Neptune, but may have
been captured from the Kuiper belt.
Thalassa: Very little is known about this second innermost satellite
of Neptune, which is named after a sea goddess from Greek my-
thology. The only things known about Thalassa is that it is irregu-
larly shaped and shows no sign of any geological modification. It is
likely that is is a rubble pile re-accreted from fragments of Nep-
tune’s original satellites, which were smashed up by perturbations
from Triton soon after that moon’s capture into a very eccentric
initial orbit. Unusually for irregular bodies, it appears to be rough-
ly disk-shaped. Since the Thalassian orbit is below Neptune’s syn-
chronous orbit radius, it is slowly spiraling inward due to tidal de-
celeration and may eventually impact Neptune’s atmosphere, or
break up into a planetary ring upon passing its Roche limit due to
tidal stretching.
Becca Bright
Information Source: http://solarsystem.nasa.gov/index.cfm
Planetary Rings
One of the most unique features of the Jovian planets lie not only in the atmospheres that seem
to dominate their visual surface, but also in their rings.
The rings of Jupi-
ter appear to be created by
dust thrown off by impacts
on small moons that orbit
within them. The outer
rings (or known as the gos-
samer rings, which are
6500 km wide) actually
outline the orbits of Amal-
thea and Thebe (two Jovian
moons). The flat main ring
is outlined by the orbits of
Adrastea and Metis (two
more Jovian moons). The
halo, or inner ring, is ap-
proximately 20000 to
40000 km in overall thick-
ness. Its shape is thought
to be due to electromag-
netic forces within Jupiter’s
magnetosphere acting on
the dust particles of the
ring.
Puzzling astrono-
mers since Galileo Galilei’s
discovery of them with his
telescope in 1610,
Saturn’s complex ring sys-
tem still has yet to be fully
understood. By far,
Saturn’s rings are the larg-
est and most spectacular.
Billions of ring particles
(made mainly of ice)
make up the entire ring
system. There are so
many rings of varying
thickness that gaps exist
between some of them,
and some large enough
for tiny moons to orbit
through. The Cassini mis-
sion (which is already or-
biting Saturn) will help us
further understand how
these magnificent rings
formed, how they main-
tain their orbit, and above
all, why they are there in
the first place.
The scientists pre-
paring to watch Uranus
pass in front of a star in
1977 were eager for this
rare chance to observe a
distant planet. But they
did not expect to find rings
surrounding the planet.
Occasionally, the star ap-
peared to blink out several
times, this was caused by
the rings blocking the star-
light. The Kuiper team
observing the planet were
able to identify 5 narrow
rings, while the Perth team
identified 6 more. Now, 15
rings have been identified
after a closer view from
the Voyager 2 spacecraft
(two of these were discov-
ered by the Hubble Space
Telescope in 2005). It is
not entirely known what
the rings are made of, but
some of the larger rings
are surrounded by belts of
fine dust.
The first evi-
dence found on Nep-
tune’s rings came from a
stellar occultation experi-
ment in the mid 1980s, an
extra “blink” was shown
just before or after the
planet occulted the star.
Images from Voyager 2 in
1989 found the planet to
be surrounded by several
faint rings. The outer-
most of these rings con-
tains three prominent
arcs. The existence of
these arcs are very diffi-
cult to understand be-
cause the laws of motion
would predict that arcs
spread out into a uniform
ring over very short time-
scales. The gravitational
effects of Galatea (a Nep-
tunian moon just inward
from the ring) are now
believed to confine the
arcs. As of today, we still
do not know of the com-
position of Neptune’s
rings.
Jupiter is the most massive planet in
our solar system, with dozens of moons
and an enormous magnetic field. Jupiter
forms a kind of miniature solar system.
People have said that Jupiter resembles a
star in composition, but did not grow big
enough to ignite. The planets swirling
cloud stripes is created by massive storms
such as the great red spot , which has
raged for hundreds of years. Jupiter also
orbits the sun and one day on Jupiter takes
Jupiter is the fifth planet from the sun at a distance of about seven hundred and seven-
ty-eight million km. Jupiter makes a complete orbit around the sun about every twelve years
which is four thousand three hundred and thirty-three earth days.
Jupiter has a gas giant planet and therefore does not have a solid surface, but it howev-
er is predicted that Jupiter has an inner solid core about the size of earth. Jupiter’s atmos-
phere is made up mostly of hydrogen and helium.
Jupiter has fifty known moons, with an additional seventeen moons awaiting confirma-
tion of their discovery that is a total of sixty-seven moons. Jupiter has a faint ring system
which was discovered in 1979 by the voyager two mission. Many missions have been made
out to Jupiter and its system of moons, Juno’s mission will arrive in 2016.
As far as we know Jupiter cannot support life, however Jupiter’s moons might be
able to support life because some of the moons provide oceans underneath their
crusts
Jupiter is a very active planet. A plethora of storms rage all over its surface, the
most famous being the 'Great Red Spot'. This is a gigantic rotating storm, wider
than 3 'Earth diameters'. It is highly complex and moves in a generally anti-
clockwise direction, and historical records of Earth-based observations show that is
has existed for at least 100 years.
Jupiter is the fourth brightest object in the solar system:
Only the Sun, Moon and Venus are brighter. It is one of five planets visible to the
naked eye from Earth.
PLUTO Pluto was discovered in 1930. Pluto
was considered our ninth planet up
until 2006. Pluto is now considered a
dwarf planet. A dwarf planet orbits the
sun just like other planets, but is
smaller. Dwarf planets are so small
that they cannot clear other objects
out of its path.
Plutos surface is icy cold. The average
temperature is 44 Kelvin, or -380
Farenheit. The surface is covered by
exotic ices such as methane and
nitrogen frost. Pluto has an estimated
diameter less than 1/5 of the earths
moon. The surface is roughly -375 degrees Farenheit. The surface looks reddish,
yellowish and grayish. When compared with past images, the Hubble pictures
show that over time Pluto has gotten redder, apparently from seasonal changes.
Pluto has five moons. One of those moons is
about half the size of Pluto. That is quite
unusual because most Planets are a lot bigger
than their moons. Pluto’s moon’s name is
Charon. Pluto and Charon are only 12,200 miles
apart. Charon’s orbit around Pluto takes 6.4
earth days. This is because Charon hovers over
the same spot on Pluto’s surface and the same
side of Charon always faces Pluto, a
phenomenon known as tidal locking.
By: Lila Kennedy
Comparison of the size of Earth to Pluto
Pluto
Pluto is the largest object in the Kuiper
belt and the second-most-massive
known dwarf planet.
Discovered in 1930, Pluto was originally
classified as the ninth planet from the
sun. Its status as a major planet fell into
question following further study of it
and outer solar system over the ensur-
ing 75 years.
Santiam Seventh Period Astronomy
Class Magazine 11/3/14
The Discovery of Pluto
By: Carlos Dela Cruz
Pluto has five known moons: Char-
on (the largest of them all). Nix, Hy-
dra, Kerberos, and Styx. Pluto and
Charon are sometimes described as
a binary system because the bary-
center of their orbits does not lie
within earlier body.
Alternate picture of Pluto.
Pluto and Charon (Plutos’ biggest moon)
Discovery of Pluto page 2
By: Carlos Dela Cruz
On July 14, 2015, the Pluto system
is due for a visit by spacecraft for
the first time. The new horiszons
probe will be passing by and taking
pictures of it. In 1978 the discovery
of plutos moon Charon allowed
the measurement of Pluto’s mass
of the first time.
Once discovered, Planet X needed a name.
Everyone had an opinion. However, the name
Pluto was chosen on March 24, 1930 after 11-
year-old Venetia Burney in Oxford, England
suggested the name "Pluto." The name de-
notes both the assumed unfavorable surface
conditions (as Pluto was the Roman god of
the underworld) and also honors Percival
Lowell, as Lowell's initials make up the first
two letters of the planet's name.
Pluto is the planet farthest from
the sun. This great distance from
the sun makes Pluto very inhospi-
table; it's surface is expected to be
made up of mostly ice and rock
and it takes Pluto 248 years just to
make one orbit around the sun.
Surfaces of the Jovian planets
A gas giant is a massive planet with a thick atmosphere of hydrogen and
helium. They may have a dense molten core of rocky elements, or the core may
have completely dissolved and dispersed throughout the planet if the planet is hot
enough. The hydrogen and helium in basic gas giants like Jupiter and Saturn
constitute most of the planet, instead they only make up an outer envelope on
Uranus and Neptune, which are sometimes called ice giants, because they are
mostly composed of water, ammonia, and methane.
Among extrasolar planets, Hot Jupiter’s are gas giants that orbit very close
to their stars and thus have a very high surface temperature. Hot Jupiter’s were,
until the advent of space borne telescopes, the most common form of extrasolar
planet known, perhaps due to the relative ease of detecting them from ground-
based instruments.
Gas giants are commonly said to lack solid surfaces, but it is more accurate
to say that they lack surfaces altogether since the gases that constitute them simply
become thinner and thinner with increasing distance from the planets' centers,
eventually becoming indistinguishable from the interplanetary medium. Therefore
landing on a gas giant may or may not be possible, depending on the size and
composition of its core.
Maelyn Leis
Though Jupiter has over sixty moons,
its four largest were discovered by Galileo Galilei in 1610 through his telescope. The names of the four moons come from Greek mythology, and are actually the names of Zeus’s four lovers,
Io, Europa, Ganymede, and
Callisto.
The radius of each is greater than even the dwarf planet Ceres in the asteroid belt.
Io is closest to
Jupiter and the fourth largest moon in the solar system. Io is covered in volcanoes and mountains, and is the most
geologically active object in the Solar System. Io has a thin atmosphere and, possibly, a magnetic field.
Europa is
second closest to Jupiter and is smaller than Earth’s moon. There could be life on Europa, since Europa has a layer of
water and ice, and if oceans do in fact exist
on Europa, life similar to that in Earth’s undersea vents could exist. Europa has a thin oxygen atmosphere, an iron core, and markings on the outside that could be the cause of gravity, or could be the cause of geyser eruptions.
Ganymede is the largest satellite in
the solar system--larger than Mercury--and orbits third from Jupiter. It is a frozen moon with a magnetic atmosphere, and, like Europa, its atmosphere is thin and primarily oxygen. The surface is grooved and cratered, but covered in a layer of ice.
Callisto is
the fourth and last moon from Jupiter and is the second largest, as well as the third largest moon in the solar system. Callisto is made up of
rock and ice, and could contain an underground ocean, which could harbor life, though it’s less likely than Europa to harbor life. Its surface is intensely cratered.
Uranus
The seventh planet in our solar system and the second
smallest of the gas giants is the title held by Uranus.
Uranus has 27 moons, all but six were discovered by the
Voyager II flyby mission. The six largest moons are named
after characters in William Shakespeare's plays: Titania,
Oberon, Ubmriel Ariel and Miranda.
Uranus has many different unique qualities from its differ-
ent name pronunciations to its extreme axial tilt.
Uranus orbits
on its side.
Pronunciations:
You’re-anus; Oo-ran-ose, Yourinus
Even though it is bigger, Uranus’ surface gravity is 8.9m/s squared compared to
Earth’s 9.78 m/s squared. Uranus’ mass is 86.81 septillion kg whereas Earth’s is
only 5.972 septillion kg. That’s 21 zeroes!
It takes Uranus eighty four Earth years to orbit the sun and the days on the
planet’s surface last about that long as well. Uranus rotates in 17 hours and 14
minutes with an average speed of 6.8 km/s.
Even though the planet rotates that quickly a Uranian day lasts about as long as
its year. As the planet moves about its orbit, its northern hemisphere is pointed
toward the sun. Then about a quarter year later the equator is pointed at the
sun. At the halfway mark the southern hemisphere is facing the sun then at three
-quarters of a year the equator is facing the sun again but in the opposite direc-
tion, then the cycle repeats.
Uranus’ atmosphere is about 4000km thick and is the coldest atmosphere of the
gas giants with an average temperature of 49 kelvin. It is mainly composed of hy-
drogen and helium at the surface, but the further down you go there is an abun-
dance of methane and ammonia.
There are 11 rings around Uranus, two of which were discovered by the only mis-
sion to the planet, Voyager II, which is no longer orbiting Uranus. Nine rings were
officially discovered in 1978, and two more when Voyager two flew by.
Uranus as seen by Voyager II
By: Braeden Cook
Weather On Jovian Planets
All 4 jovian planets have distinct
atmospheres with cloud layers that
govern the different types of gases that
can condense.
Jupiter's weather is by far the strongest
and most active of the jovian planets,
but weather is found on all four.
Saturn has stripes of alternating color
and wind direction, though in more
color. Even though Saturn has an axis
tilt similar to that of Earth, we don't see
the dramatic seasons we might expect.
Some weather changes have been
seen, but Saturn's internal heat keeps
temperatures about the same.
Uranus is tipped on its side so scientists would expect it to
go through extreme changes during its 84-year orbit around
the Sun. When Voyager 2 flew past in 1986, Uranus's
northern hemisphere was facing directly toward the Sun,
and its southern hemisphere was surrounded by darkness.
Photographs revealed no clouds. More recent observations
show storms in Uranus's atmosphere. The storms may be
there because of the changing seasons as the southern
hemisphere sees sunlight for the first time in decades.
Neptune's atmosphere is banded, and has a high-pressure
storm, called the Great Dark Spot, that is like Jupiter's Great
Red Spot. The Great Dark Spot disappeared in 1994, but was
replaced with a similar storm soon after. Like Saturn,
Neptune has an axis tilt similar to Earth's but it has relatively
little seasonal change because of its internal heat. The heat
created in Neptune's interior is released uniformly and
keeps the temperature about the same year-round and
planet-wide.
By: Lila
Kennedy
10-30-14
7th Period