Jovian Planets Magazine Front page layout by: Carlos De la Cruz and Salvador Winn
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.
Neptune
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.
Uranus
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.
Mars is a terrestrial planet
Becca Bright
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 Jupiter) is named after a priestess of Hera in Greek mythology, who was also one of Zeus/Jupiter’s lovers. Nicknamed the “cosmic pizza,” Io is the most geologically active body in our Solar System with over 400 active volcanoes. Io is also possibly the most colorful object 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 Europa, a Phoenician woman of high lineage in Greek mythology, 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 confirming 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 mythology, and is one of Zeus/Jupiter’s many lovers. Ganymede is also the only moon known to possess a magnetosphere. Its diameter 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. Information Source: http://en.wikipedia.org/wiki/Main_Page
Becca Bright 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 evidence of stable bodies of surface liquid. The climate (which includes wind and rain) creates surface features similar to those of Earth’s. Dunes, rivers, lakes, seas, and deltas can form from Titan’s wind and rain. On June 23, 2014, NASA found strong evidence that the nitrogen in Titan’s atmosphere came from materials 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. Enceladus 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 released 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 surface features. The most prominent feature on Tethys is an impact 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 resurfacing event that obliterated its outer surface. Its most prominent feature is a ring of bright material on the floor of Wunda crater.
Information Source: http://en.wikipedia.org/wiki/Main_Page
Becca Bright 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 appears to have been shaped by both impacts and endogenic processes. Not very much is known about Titania, but infrared 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 retrograde, the only large moon in the Solar System with such an orbit. This, along with its composition (mostly frozen nitrogen, a mostly water ice crust, an icy mantle, and a substantial 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 mythology. The only things known about Thalassa is that it is irregularly shaped and shows no sign of any geological modification. It is likely that is is a rubble pile re-accreted from fragments of Neptune’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 roughly disk-shaped. Since the Thalassian orbit is below Neptune’s synchronous orbit radius, it is slowly spiraling inward due to tidal deceleration and may eventually impact Neptune’s atmosphere, or break up into a planetary ring upon passing its Roche limit due to tidal stretching.
Information Source: http://en.wikipedia.org/wiki/Main_Page
Becca Bright
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 Jupiter appear to be created by dust thrown off by impacts on small moons that orbit within them. The outer rings (or known as the gossamer rings, which are 6500 km wide) actually outline the orbits of Amalthea 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 approximately 20000 to 40000 km in overall thickness. Its shape is thought to be due to electromagnetic forces within Jupiter’s magnetosphere acting on the dust particles of the ring.
Puzzling astronomers since Galileo Galilei’s discovery of them with his telescope in 1610, Saturn’s complex ring system still has yet to be fully understood. By far, Saturn’s rings are the largest 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 mission (which is already orbiting Saturn) will help us further understand how these magnificent rings formed, how they maintain their orbit, and above all, why they are there in the first place.
Information Source: http://solarsystem.nasa.gov/index.cfm
The scientists preparing 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 appeared to blink out several times, this was caused by the rings blocking the starlight. 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 discovered 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 evidence found on Neptune’s rings came from a stellar occultation experiment 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 outermost of these rings contains three prominent arcs. The existence of these arcs are very difficult to understand because the laws of motion would predict that arcs spread out into a uniform ring over very short timescales. The gravitational effects of Galatea (a Neptunian moon just inward from the ring) are now believed to confine the arcs. As of today, we still do not know of the composition 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 seventy-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 however 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 confirmation 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 anticlockwise 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 Comparison of the size of Earth to Pluto 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. Pluto
By: Lila Kennedy
Santiam Seventh Period Astronomy Class Magazine 11/3/14 The Discovery of Pluto By: Carlos Dela Cruz 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 ensuring 75 years.
Pluto has five known moons: Charon (the largest of them all). Nix, Hydra, Kerberos, and Styx. Pluto and Charon are sometimes described as a binary system because the barycenter of their orbits does not lie within earlier body.
Pluto and Charon (Plutos’ biggest moon)
Alternate picture of Pluto.
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.
Pluto is the planet farthest from the sun. This great distance from the sun makes Pluto very inhospitable; 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.
Once discovered, Planet X needed a name. Everyone had an opinion. However, the name Pluto was chosen on March 24, 1930 after 11year-old Venetia Burney in Oxford, England suggested the name "Pluto." The name denotes 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.
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 groundbased 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
By: Braeden Cook
Pronunciations: You’re-anus; Oo-ran-ose, Yourinus
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 different name pronunciations to its extreme axial tilt.
Uranus orbits on its side.
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 direction, then the cycle repeats.
Uranus as seen by Voyager II
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 hydrogen and helium at the surface, but the further down you go there is an abundance of methane and ammonia. There are 11 rings around Uranus, two of which were discovered by the only mission 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.
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.
By: Lila Kennedy 10-30-14 7th Period
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.