Saturday 31 December 2016 - 14:20:45 Posted by  Bobby

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 Jupiter is a giant among the planets. It is the second-largest body in the solar system after the Sun and the most massive of all the planets. Its visible surface is not solid but the colorful top layer of a deep, thick atmosphere. An extensive family of moons orbits around Jupiter, and a thin faint ring of dust and particles encircles it.

Great Red Spot

 Jupiter's cloudy atmosphere is dominated by storms. The smallest are like Earth's largest hurricanes. The biggest, the Great Red Spot, is bigger than Earth itself. On the left is the shadow of the moon Europa.

Little Red Spot

 In late 2005, astronomers witnessed the birth of Jupiter's second red spot, and second-largest storm - about 70% of the size of Earth. It formed between 1998 and 2000 when three white, oval-shaped storms emerged.

The King of the Planets


 Jupiter is the largest planet in the Solar System. It is truly huge, with an equatorial diameter of 88,846 miles - eleven times wider than Earth.

 It's also one of the best-known sites in the sky for stargazers and amateur astronomers, being bright and prominent. Only the Sun, the Moon, Venus, (and sometimes Mars), are brighter. Through a telescope, at least four of its moons can be seen as tiny pinpricks of light, and the banding of its cloud patterns is easily visible. Its prominence in the night sky means that it has been known to mankind since antiquity, and it has played a role in the mythologies and legends of many peoples across Earth. It is named for the chief god of Roman mythology.

 Like the other giant planets of the Solar System - Saturn, Uranus, and Neptune - when we look at Jupiter we do not see a solid surface, such as we do with the four inner planets. Rather, we see the tops of clouds.

 Jupiter is a "gas giant," composed of roughly 75% hydrogen (by mass) and about 25% helium with trace amounts of other gases. It has not been confirmed, but it is suspected, that there is a rocky core right in the middle of the planet. On top of that is hydrogen that has become so squashed by the intense pressures, that it has turned into liquid metallic hydrogen. Above this is a region of liquid hydrogen and helium that gradually gives away to hydrogen and helium gas as it gets closer to the visible surface. At the very top of the atmosphere are cloud layers composed of ammonia ice crystals, and possibly some ammonium hydrosulfide and water/water ice. It was hoped that the Galileo atmospheric probe would detect some significant amounts of water in one of the cloud layers during its descent into the atmosphere, but in the end it didn't. Scientists think the probe just happened to strike a "dry" region.

Big Brother


 Jupiter rotates faster than any other planet in the Solar System, completing a rotation in just over 9 hours 55 minutes. This rapid rotation has made the planet "flatten out" into an oblate spheroid, with a sideways bulge at the equator. Being a non-solid planet, the atmosphere actually rotates at slightly different rates depending on the latitude - for instance, the poles rotate about five minutes slower than the equator.

 Jupiter orbits the Sun in a roughly circular orbit which, at its's closesr point, is just under 5 times - 460 million miles - further from the Sun than Earth is, and at its furthest point is just under 5.5 times the distance between Earth and the Sun, approximately 507.4 million miles. Its orbit is inclined only slightly - 1.3 degrees to the ecliptic plane. Jupiter's year - the time it takes to complete one orbit - is 11.9 Earth years.

 Its position in the middle of the Solar System, and it's large gravitational field, make it a dominant player in the movement of small Solar System bodies, such as asteroids and comets. It is responsible for keeping some of them in their orbits, while others are flung onto different trajectories if they get too close to the giant planet.

 Jupiter has often been called a "failed star." It is less than 1% as massive as the Sun. If it had been only about a dozen times more massive it would have become a "brown dwarf," a feeble kind of star that emits a small amount of heat. If it had been around 80 times as massive, it would have become a true (though small) star.

 An intriguing fact is that Jupiter actually puts out about as much heat as it receives from the Sun. All that energy is then slowly released as the planet continues to slowly contract over its life, making it now half the diameter it was on formation.

Cloudy Weather


 Through even a small telescope, it can be seen that Jupiter's visible surface is divided into distinct bands or stripes. These are cloud patterns that circle the planet - dark colored bands are known as belts, while the lighter colored bands are called zones.

 Each hemisphere is divided into three main belts and three main zones, with an extra zone straddling the equator. There are also two polar regions, and several other belts and zones that come and go. The Great Red Spot is located within the south equatorial belt and south tropical zone.

 The different colorations of the zones and belts reflect the gases that make up the clouds, and the clouds themselves are in three layers. The top white layer is made of ammonia; the middle layer is ammonium hydrosulfide, which gives it its reddish brown color; and below that is a layer of water clouds, but these are not usually visible underneath the two top layers.

 Like Earth, Jupiter has circulation patterns that give it its complex climate system. Warm air near the equator moves towards the poles, and cold air moves away from the poles, which combined with the strong Coriolis effect caused by Jupiter's rapid rotation, leads to the creation of the strong atmospheric currents.

Rings of Jupiter


 Like Saturn, Jupiter, too, has a system of rings, although nowhere near as spectacular as Saturn's. Jupiter's ring system is made up of what are believed to be dust particles, unlike Saturn's, which are made of chunks of ice.

 Hardly anyone suspected that Jupiter might have rings, but some researchers with the Voyager 1 Mission convinced mission controllers to get the spacecraft to look for them during its flyby in March 1979. It found three rings: the inner halo torus (that is, it is shaped like a donut,with the thickest part of its cross-section in the middle), a brighter main ring, and a three-part gossamer ring.

 The Rings have small moons associated with them, and scientists think the rings are composed of material blasted from the surface of these moons by meteorites.

 Metis and Adrastea are the two moons responsible for the main ring, while the gossamer ring is most likely to be associated with Amalthea and Thebe.

 The halo torus extends out from about 55,300 to 76,400 miles measured from Jupiter's center; the main ring extends from 76,400 to 80,000 miles; and the gossamer ring out from about 80,000 to 174,000 miles.

The Magnetosphere


 Jupiter has a magnetic field that is both very strong and very large, extending far out into space - so large that the Sun and its corona could easily fit within it. If it could be seen from Earth, it would be several times the size of the Moon. Jupiter's magnetosphere is, in fact, the largest thing in the solar system. It is believed to be generated by electrical currents in the metallic hydrogen core of the planet. The magnetosphere of Jupiter reaches out about 3 million miles in front of the planet in the direction of the Sun, but can stretch out to an amazing 400 million miles behind the planet and a long tail - that's out beyond the orbit of Saturn in fact!

 Contained with the magnetic field is a mixture of hydrogen, helium, oxygen, and sulfur ions. The sulfur comes from the Moon lo, which has volcanoes that spew large quantities of sulfur into space. Some of this sulfur is swept up by the magnetic field on Jupiter into a torus (donut-shaped ring) that surrounds Jupiter at Io's orbital distance.

Galilean moons

 Jupiter's four largest moons are collectively known as the Galilean moons. These spherical bodies made of a mix of rock and ice are worlds in their own right. By contrast, most of the other moons are small and irregular in shape.

Moons of Jupiter


 With 63 satellites, Jupiter is surrounded by its own solar system. Apart from the four large Galilean moons, only a handful measure more than a few kilometers across. Ganymede, with a diameter of 5,262 kilometers (3,280 miles), is larger than Mercury (a distinction it shares with Saturn's Titan) and the largest moon in the solar system.


 Untroubled by geological activity, Callisto presents us with the solar system's most ancient landscape. Unchanged for over 4 billion years, its icy face is heavily pockmarked by impact craters, the largest of which, Valhalla, can be seen here the impact basin is 600 kilometers (375 miles) across, and is surrounded by concentric ripples that extend over a third of the way around the moon.


 Tormented by the gravitational tides of its sister moons and its parent, Io is convulsed by in this volcanic activity. Glowing a sulfurous yellow, it's hellish landscape is dominated by seas of lava. Massive eruptions - the plume silhouetted on Io's edge is 140 kilometers (86 miles) high - are turning the moon inside out at a rate of 1 centimeter every 3,000 years.


The same gravitational flux that has condemned Io to its infernal fate may have created a dark paradise 25 kilometers (15 miles) beneath that pack ice of Europa's surface. Here, warmed by thermal vents, a salty ocean may nurture life. If this is the case, we will know life can't be a fluke, that given the right conditions it is almost inevitable and we should expect to encounter it throughout the cosmos.

 Jupiter Statistics

Discovered Known from antiquity
Average distance from the Sun 483.8 million miles (778.6 million km) 5.2 AU
Equatorial diameter 88,846 miles (142,984 km)
Axial tilt 3.12°
Axial rotation period (sidereal) 9.92 hours
Orbital period (in Earth years) 11.8565 years
Mass (Earth=1) 317.8
Volume (Earth=1) 1,321
Gravity at cloud tops (Earth=1) 2.64
Average density (water=1) 1.3
Escape velocity 37 miles/s (59.5 km/s)
Sunlight strength 3-4% of Earth's
Albedo (reflectivity) 52%
Number of satellites 63

 Jupiter Timeline

c. 3300 BCE
Babylonian Empire shows records of their knowledge of Jupiter's existence.
c. 3000 BCE
Ancient Greek astronomy records knowledge of the planet Jupiter.
c. 2000 BCE
Chinese astronomers keep records of Jupiter's orbit.
1200 BCE - 476 CE
Roman records of Jupiter are kept. In 476 CE. Chinese astronomer, GanDe, makes observations of a body which is now believed to be Ganymede, a moon of Jupiter.
Galileo discovers Jupiter's four largest moons: Callisto, Europa, Ganymede, and Io. They have since been known as the Galilean moons.
A British chemists and physicists, Robert Hooke, discovers Jupiter's Great Red Spot.
Amalthea, another satellite of Jupiter, is discovered by Edward Barnard.
Himalia, a large moon, is discovered by Charles Perrine, the US astronomer. Himalia has a diameter of 105 miles (107 km) and is the largest in the group that now bears its name. Perrine goes on to discover Elara the following year.
Pasiphae, a moon of Jupiter, its discovered by astronomer, Philibert Melotte.
Sinope, a retrograde irregular moon of Jupiter, is discovered by Seth Barnes Nicholson. It is named after Sinope of Greek mythology.
Lysithea and Carme are also discovered by Seth Barnes Nicholson.
Yet another Moon, Ananke, is once again discovered by Nicholson.
Kenneth Franklin, US astronomer, detects some radio transmissions from the planet.
Jupiter is visited by Pioneer 10, the first spacecraft to travel through the Asteroid Belt and reach the outer Solar System.
Leda discovered by Charles Kowa. Space probe Pioneer 11 reaches Jupiter and uses the planet's gravitational force to send it on past Saturn and onto other regions of the Solar System. It lost contact with Earth in 1996.
Themisto, another moon, is discovered by astronomers Elizabeth Roemer and Charles Kowal.
Thebe and Metis are discovered by Stephen Synnott. Voyager 1 discovers Jupiters rings. Voyager 2 also visits Jupiter.
Hubble Space Telescope sends first images of Jupiter, revealing details never imagined before. Hubble continues to return data helping to improve our knowledge of Jupiter and the Solar System.
Space probe Ulysses passes Jupiter, using its gravity to hurl it onto the correct trajectory for its examination of the Sun. During its Jupiter flyby, scientists use its instruments to discover more of the planet.
Fragments of comet Shoemaker-Levy 9 collide with Jupiter, leaving large "scars" on the southern surface. It is observed by scientists around the world.
Another new moon, S/1999 J1, is discovered.
Cassini-Huygens probe passes Jupiter on a fly by. It's on its way to Saturn but is deliberately sent via Jupiter to uncover new information. It reveals a vast whirling bubble of charged particles surrounding Jupiter.
Due to the rapid increase in technology, 11 new moons are discovered.
Galileo probe plunges into Jupiter's atmosphere and is destroyed.

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