Jupiter
Jupiter is the fifth planet from the Sun and by far the largest within our solar system; some have described the solar system as consisting of the Sun, Jupiter, and assorted debris. It and the other gas giants Saturn, Uranus, and Neptune are sometimes referred to as "Jovian planets." The Romans named the planet after the Roman god Jupiter. The astronomical symbol for the planet is a stylized representation of the god's lightning bolt. The Chinese, Korean, and Japanese cultures refer to the planet as the Wood Star, based on the Five Elements.
Overview
Jupiter has been known since ancient times and is visible to the naked eye in the night sky. In 1610, Galileo Galilei discovered the four largest moons of Jupiter using a telescope, the first observation of moons other than Earth's.
Jupiter is 2.5 times more massive than all the other planets combined, so massive that its barycenter with the Sun actually lies above the Sun's surface (1.068 solar radii from the Sun's center). It is 318 times more massive than Earth, with a diameter 11 times that of Earth, and with a volume 1300 times that of Earth. It has been termed by many a "failed star", even though the comparison would be akin to calling an asteroid "a failed Earth". As impressive as it is, extrasolar planets have been discovered with much greater masses. However, it is thought to have about as large a diameter as a planet of its composition can, as adding extra mass would only result in further gravitational compression (until ignition occurs). There is no clear-cut definition of what distinguishes a large and massive planet such as Jupiter from a brown dwarf, although the latter possesses rather specific spectral lines, but in any case Jupiter would need to be about seventy times as massive if it were to become a star.
Jupiter also has the fastest rotation rate of any planet within the solar system, making a complete revolution on its axis in slightly less than ten hours, which results in a flattening easily seen through an Earth-based amateur telescope. Its best known feature is probably the Great Red Spot, a storm larger than Earth. The planet is perpetually covered with a layer of clouds.
Jupiter is usually the fourth brightest object in the sky (after the Sun, the Moon and Venus; however at times Mars appears brighter than Jupiter, while at others Jupiter appears brighter than Venus). It has been known since ancient times. Galileo Galilei's discovery, in 1610, of Jupiter's four large moons Io, Europa, Ganymede and Callisto (now known as the Galilean moons) was the first discovery of a celestial motion not apparently centered on the Earth. It was a major point in favor of Copernicus' heliocentric theory of the motions of the planets; Galileo's outspoken support of the Copernican theory got him in trouble with the Inquisition.
Physical Characteristics
Jupiter is composed of a relatively small rocky core, surrounded by metallic hydrogen, surrounded by liquid hydrogen, which is surrounded by gaseous hydrogen. There is no clear boundary or surface between these different phases of hydrogen; the conditions blend smoothly from gas to liquid as one descends.
The atmosphere contains trace amounts of methane, water vapour, ammonia, and "rock". There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. The outermost layer of the atmosphere contains crystals of frozen ammonia.This atmospheric composition is very close to the composition of the solar nebula. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium.
Jupiter's upper atmosphere undergoes differential rotation, an effect first noticed by Giovanni Cassini (1690). The rotation of Jupiter's polar atmosphere is ~5 minutes longer than that of the equatorial atmosphere. In addition, bands of clouds of different latitudes flow in opposing directions on the prevailing winds. The interactions of these conflicting circulation patterns cause storms and turbulence. Wind speeds of 600 km/h are not uncommon. A particularly violent storm, about three times Earth's diameter, is known as the Great Red Spot.
The Great Red Spot is an anticyclonic storm on the planet Jupiter, 22° south of the equator; which has lasted at least 300 years. The storm is large enough to be visible through Earth-based telescopes. It was first observed either by Cassini or Hooke around 1665.
This dramatic view of Jupiter's Great Red Spot and its surroundings was obtained by Voyager 1 on February 25, 1979, when the spacecraft was 5.7 million miles (9.2 million kilometers) from Jupiter. Cloud details as small as 100 miles (160 kilometers) across can be seen here. The colorful, wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex and variable wave motion. To give a sense of Jupiter's scale, the white oval storm directly below the Great Red Spot is approximately the same diameter as Earth.
Storms such as this are not uncommon within the atmospheres of gas giants. Jupiter also has white ovals and brown ovals, which are lesser unnamed storms. White ovals tend to consist of relatively cool clouds within the upper atmosphere. Brown ovals are warmer and located within the "normal cloud layer". Such storms can last hours or centuries.
It is not known exactly what causes the Great Red Spot's reddish color. Theories supported by laboratory experiments suppose that the colour may be caused by any of "complex organic molecules, red phosphorus, or yet another sulfur compound", but a consensus has yet to be reached.
The Great Red Spot is remarkably stable, having first been spotted over 300 years ago. Several factors may be responsible for its longevity, such as the fact that it never encounters solid surfaces over which to dissipate its energy and that its motion is driven by Jupiter's internal heat. Simulations suggest that the Spot tends to absorb smaller atmospheric disturbances.
At the start of 2004, the Great Red Spot is approximately half as large as it was 100 years ago. It is not known how long the Great Red Spot will last, or whether this is a result of normal fluctuations.
The Great Red Spot should not be confused with the Great Dark Spot, famously seen in the atmosphere of Neptune by Voyager 2 in 1989. The Great Dark Spot was an atmospheric hole, not a storm, and was no longer present as of 1994 (although another, similar spot had appeared farther to the north).
On October 19, 2003 a black spot was photographed on Jupiter by Belgian astronomer Olivier Meeckers. Although not an unusual occurrence, this one caught the fantasy of some science fiction fans and conspiracy theorists, who went as far as speculating that the spot was evidence of nuclear activity on Jupiter, caused by Galileo's crash into the planet a month prior. Galileo carried about 15.6 kg of plutonium-238 as its power source, in the form of 144 pellets of plutonium dioxide, a ceramic. The individual pellets (which would be expected to separate during entry) initially contained about 108 grams of 238Pu each (about 10% would have decayed away by the time Galileo entered Jupiter), and are short of the required critical mass by a factor of about 100.
Planetary Rings
Jupiter has a faint planetary ring system composed of smoke-like dust particles knocked from its moons by meteor impacts. The main ring is made of dust from the satellites Adrastea and Metis. Two wide gossamer rings encircle the main ring, originating from Thebe and Amalthea. There is also an extremely tenuous and distant outer ring that circles Jupiter backwards. Its origin is uncertain, but this outer ring might be made of captured interplanetary dust.
Magnetosphere
Jupiter has a very large and powerful magnetosphere. In fact, if you could see Jupiter's magnetic field from Earth, it would appear five times as large as the full moon in the sky despite being so much farther away. This magnetic field collects a large flux of particle radiation in Jupiter's radiation belts, as well as producing a dramatic gas torus and flux tube associated with Io. Jupiter's magnetosphere is the largest planetary structure in the solar system.
The Pioneer probes confirmed the existence that Jupiter's enormous magnetic field is 10 times stronger than Earth's and contains 20,000 times as much energy. The sensitive instruments aboard found that the Jovian magnetic field's "north" magnetic pole is at the planetıs geographic south pole, with the axis of the magnetic field tilted 11 degrees from the Jovian rotation axis and offset from the center of Jupiter in a manner similar to the axis of the Earth's field. The Pioneers measured the bow shock of the Jovian magnetosphere to the width of 26 million kilometres (16 million miles), with the magnetic tail extending beyond Saturnıs orbit.
The data showed that the magnetic field fluctuates rapidly in size on the sunward side of Jupiter because of pressure variations in the solar wind, an effect studied in further detail by the two Voyager spacecraft. It was also discovered that streams of high-energy atomic particles are ejected from the Jovian magnetosphere and travel as far as the orbit of the Earth. Energetic protons were found and measured in the Jovian radiation belt and electric currents were detected flowing between Jupiter and some of its moons, particularly Io.
Exploration of Jupiter
Pioneer 10 flew past Jupiter in December of 1973, followed by Pioneer 11 exactly one year later. They provided important new data about Jupiter's magnetosphere, and took some low resolution photographs of the planet.
Voyager 1 flew by in March 1979 followed by Voyager 2 in July of the same year. The Voyagers vastly improved our understanding of the Galilean moons and discovered Jupiter's rings. They also took the first close up images of the planet's atmosphere.
In February 1992, Ulysses solar probe performed a flyby of Jupiter at a distance of 900,000 km (6.3 Jovian radii). The flyby was required to attain a polar orbit around the Sun. The probe conducted studies on Jupiter's magnetosphere. Since there are no cameras onboard the probe, no images were taken. In February 2004, the probe came again in the vicinity of Jupiter. This time distance was much greater, about 240 million km.
So far the only spacecraft to orbit Jupiter is the Galileo orbiter, which went into orbit around Jupiter in December 7, 1995. It orbited the planet for over seven years and conducted multiple flybys of all of the Galilean moons and Amalthea. The spacecraft also witnessed the impact of Comet Shoemaker-Levy 9 into Jupiter as it approached the planet in 1994, giving a unique vantage point for this spectacular event. However, the information gained about the Jovian system from the Galileo mission was limited by the failed deployment of its high-gain radio transmitting antenna.
An atmospheric probe was released from the spacecraft in July, 1995. The probe entered the planet's atmosphere in December 7, 1995. It parachuted through 150 km of the atmosphere, collecting data for 58 minutes, before being crushed by the extreme pressure to which it was subjected. It would have then quickly melted and vaporized. The Galileo orbiter itself underwent a more rapid version of the same fate when it was deliberately crashed into the planet on September 21, 2003 at a speed of over 50 km/s, in order to avoid any possibility of it crashing into and possibly contaminating Europa, one of the Jovian moons.
In 2000, the Cassini probe, en route to Saturn, flew by Jupiter and provided some of the highest-resolution images ever made of the planet.
NASA is planning a mission to study Jupiter in detail from a polar orbit. Named Juno, the spacecraft is planned to launch by 2010.After the discovery of a liquid ocean on Jupiter's moon Europa, there has been great interest to study the icy moons in detail.
A mission proposed by NASA was dedicated to study them. The JIMO (Jupiter Icy Moons Orbiter) was expected to be launched sometime after 2012. However, the mission was deemed too ambitious and its funding was cancelled.
In 2007, Jupiter will also be briefly visited by the New Horizons probe, en route to Pluto.
Jupiter's Moons
Jupiter has at least 63 moons. For a complete listing of these moons, please see Jupiter's natural satellites. For a timeline of their discovery dates, see Timeline of natural satellites.The four large moons, known as the "Galilean moons", are Io, Europa, Ganymede and Callisto.
The orbits of Io, Europa, and Ganymede, the largest moon in the solar system, form a pattern known as a Laplace resonance; for every four orbits that Io makes around Jupiter, Europa makes exactly two orbits and Ganymede makes exactly one. This resonance causes the gravitational effects of the three moons to distort their orbits into elliptical shapes, since each moon receives an extra tug from its neighbors at the same point in every orbit it makes. Without this resonance, tidal forces would tend to circularize the moons' orbits over time.
The tidal force from Jupiter, on the other hand, works to circularize their orbits. This constant tug of war causes regular flexing of the three moons' shapes, Jupiter's gravity stretches the moons more strongly during the portion of their orbits that are closest to it and allowing them to spring back to more spherical shapes when they're farther away. This flexing causes tidal heating of the three moons' cores. This is seen most dramatically in Io's extraordinary volcanic activity, and to a somewhat less dramatic extent in the geologically young surface of Europa indicating recent resurfacing.
Classification of Jupiter's moons
It used to be thought that Jupiter's moons were arranged neatly into four groups of four, but recent discoveries of many new small outer moons have complicated the division; there are now thought to be six main groups, although some are more distinct than others.
2. The four Galilean moons were all discovered by Galileo Galilei, orbit between 400,000 and 2,000,000 km, and include some of the largest moons in the solar system.
3. Themisto is in a group of its own, orbiting halfway between the Galilean moons and the next group.
4. The Himalia group is a tightly clustered group of moons with orbits around 11-12,000,000 km from Jupiter.
5. Carpo is another isolated case; at the inner edge of the Ananke group, it revolves in the direct sense.
6. The Ananke group is a group with rather indistinct borders, averaging 21,276,000 km from Jupiter with an average inclination of 149 degrees.
7. The Carme group is a fairly distinct group that averages 23,404,000 km from Jupiter with an average inclination of 165 degrees.
8. The Pasiphaë group is a disperse and only vaguely distinct group that covers all the outermost moons.
It is thought that the groups of smaller moons may each have a common origin, perhaps as a larger moon or captured body that broke up into the existing moons of each group.
Jupiter Wikipedia
Jupiter and Saturn full of liquid metal helium PhysOrg - August 6, 2008
Jupiter Gains New Red Spot National Geographic - May 23, 2008
Jupiter's Three Red Spots NASA - May 23, 2008
Jupiter moon's poles 'wandered' far and wide New Scientist - May 14, 2008
Jupiter's Rings Are Shaped By Interplay Of Sunlight And Shadow Science Daily - May 1, 2008
Soap bubbles recreate Jupiter's turbulent storms - the Great Red Spot New Scientist - April 10, 2008
Volcanic Moon Creates Glowing Aurora Spots on Jupiter National Geographic - March 20, 2008
Mystery Of Jupiter's Jets Uncovered Science Daily - January 25, 2008
Mystery of Io's Atmosphere Solved Live Science - October 15, 2007
Pluto-bound probe's Jupiter vista BBC - October 10, 2007
Lightning Strikes, Changing Climate Revealed on Jupiter National Geographic - October 9, 2007
"Missing" Moons, "Dirty" Ice Among Jupiter Flyby Finds National Geographic - October 9, 2007
Have Jupiter's smallest moons been obliterated? New Scientist - October 9, 2007
First Proof of Wet "Hot Jupiter" Outside Solar System National Geographic - July 11, 2007
Hubble Watches As Jupiter Changes Stripes Space.com - June 29, 2007
Giant Volcanic Plume Bursts From Jupiter Moon National Geographic - May 2, 2007
Spacecraft returns Jupiter images - Volcanic Plumes BBC - May 2, 2007
Big Auroras on Jupiter NASA - April 4, 2007
Probe spies Jupiter's moon Io, volcanic plume as it erupts BBC - March 1, 2007
By Jupiter, scientists find 'Red Spot Jr.' CNN - July 31, 2006
Red Spot Jr. is about as wide as Earth's diameter and formed from the merger of three white spots very recently, sometime between 1998 and 2000, and only turned red in December 2005, the astronomers said in a statement. The Great Red Spot is nearly twice its smaller companion's size and has been circling Jupiter for at least 342 years. But the two are located in the same area and appear to be racing each other around the planet. The two spots are about the same color when seen in visible light, but Red Spot Jr. was much darker when viewed at infrared wavelengths, the scientists said. That difference could mean the smaller storm's cloud tops are lower than the big storm's.
New Storm on Jupiter Hints at Climate Change Space.com - May 5, 2006
Jupiter is growing a new red spot and the Hubble
Space Telescope is photographing the scene.
Jupiter growing another red spot BBC - March 7, 2006
Jupiter's New Red Spot NASA - March 3, 2006
Icy Jupiter Moon Throws A Curve Ball At Formation Theories Science Daily - June 2, 2005
Jovian Lights Astrobiology Magazine - March 2005
Scientists have obtained new insight into the unique
power source for many of Jupiter's auroras
Remnants of 1994 Comet Impact Leave Puzzle at Jupiter Space.com - August 2004
Scientists discover Jupiter's largest moon Ganymede has a lumpy interior Science Daily - August 2004
Hottest Body Outside The Sun: Researchers Show Jupiter's Science Daily - June 2004
Moon Io Vaporizing Rock Gases Into Atmosphere - It is Volcanic
Jupiter spots disappear amid major climate change Space.com - April 2004
Jupiter is undergoing major climate change and could lose
many of its large spots over the next seven years, only to
make way for the creation of fresh spots in a decades-long
cycle, according to a new explanation of old mysteries.
Europa Diary - Life on Ice Space.com - May 2003
The ice shell of Europa, a moon of Jupiter, is probably about
25 kilometres (15 miles) thick, according to scientists.
Dark Spot on Jupiter Bigger than Famed Great Red Spot Space.com - March 2003
Seven new moons discovered orbiting Jupiter BBC - March 2003
Jupiter moon 'full of holes' BBC - December 2002
Io blows its top BBC - November 2002
The most powerful eruption ever detected on any planet in our
Solar System has been seen on Io, one of Jupiter's moons.
Jupiter moon's 'elevator of life' BBC - November 2002
Europa's icy crust may cover a life-filled ocean
Another Jupiter Twin Found in Flood of Planet Discoveries Space.com - June 2002
Astronomers Discover 11 More Small Moons Of Jupiter May 2002 - Science Daily
We have found 39 moons -
nine more than the previous record of Saturn.
The moons are also called satellites.
In Roman mythology, Jupiter held the same role as Zeus in the Greek pantheon. He was called Juppiter Optimus Maximus Soter (Jupiter Best, Greatest, Saviour) as the patron deity of the Roman state, in charge of laws and social order. He was the chief god of the Capitoline Triad, with Juno and Minerva.
Jupiter is a vocative compound derived from archaic Latin Iovis and pater (Latin for father), this was also used as the nominative case. Jove is an English formation based on Iov-, the stem of oblique cases of the Latin name. Its Vedic equivalent is Dyaus Pita. The name of the god was also adopted as the name of the planet Jupiter, and was the original namesake of the weekday that would come to be known in English as Thursday (the etymological root can be seen in various Romance languages, including (accusative Iovem, genitive Iovis, dative Iovi and ablative Iove - an irregular declension). Linguistic studies identify his name as deriving from the Indo-European compound "O Father God", the Indo-European deity from whom also derive the Germanic Tiwaz (after whom Tuesday was named), the Greek Zeus, and the French jeudi, Castilian jueves, Italian giovedì and Catalan dijous, all from Latin Iovis Dies, whereas English takes his Norse equivalent, Thor).
The largest temple in Rome was that of Jupiter Optimus Maximus on the Capitoline Hill. Here he was worshipped alongside Juno and Minerva, forming the Capitoline Triad. Jupiter was also worshipped at Capitoline Hill in the form of a stone, known as Iuppiter Lapis or the Jupiter Stone, which was sworn upon as an oath stone. Temples to Juppiter Optimus Maximus or the Capitoline Triad as a whole were commonly built by the Romans at the center of new cities in their colonies.
It was once believed that the Roman god Jupiter was in charge of cosmic Justice, and in ancient Rome, people swore to Jove in their courts of law, which lead to the common expression "By Jove!", still used as an archaism today. In addition, "Jovial" is a medium-common adjective still used to describe people who are jolly, optimistic, and buoyant in temperament.
In Greek mythology, Jupiter is Zeus or Z, the king of heaven and Earth and of all the Olympian gods. He is depicted with lightning bolts to remind us that reality is created by electromagetic energy which moves the magic and mystery of our program through grid consciousness, towards Zero Point.
In Roman mythology, Jupiter was known as the god of justice. He was named king of the gods in the special meeting that followed his overthrow of the god Saturn (Cronus in Greek mythology) and the Titans. In the council of the gods that followed Saturn's overthrow, Jupiter was crowned Lord of Heaven and Earth and of all the gods.
Jupiter granted Neptune dominion over the Sea,
and his other brother Pluto dominion over the underworld.
If Jupiter's satellite, Europa, has oceans as many suspect, there is a theory that extraterrestrial life could exist there. Fishing for aliens Guardian - July 18, 2002
A metaphysical theory states that life on European is connected to the dolphins on planet Earth, communication via telepathic tones.
Jupiter as Zeus or Z, is depicted as throwing zig-zig lightning bolts to remind us that reality is created by electromagetic energy which moves the magic and mystery of our program through grid consciousness, towards Zero Point.
Jupiter is the method each of us has for dealing with the laws of life, our Saturn or limitations. The Hindu word for Jupiter is Guru and this planet indicates our particular Dharma, the way we can solve the problems that confront us. Thus Jupiter has to do with our vocation, the way in which we can be successful. Jupiter is the light or path. The largest planet in the solar system, Jupiter represents the principles of growth and expansion.
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