Portal:Jupiter

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Jupiter

Cloud bands are clearly visible on Jupiter. Credit: NASA/JPL/USGS.

Jupiter is the largest planet in the Solar System and contains nearly 3/4 of all planetary matter.

With no solid surface, Jupiter is a gas and liquid filled giant. Its turbulent belts of clouds circulate parallel to the equator and often contain oval spots which are storm systems with the largest being easily twice the diameter of Earth. The great red spot has been observed for at least 300 years and rotates counter-clockwise with wind speeds of 270 miles per hour [430 km/hr].

Although observed and studied from Earth for centuries it wasn't until the mid 1970's that humans were able to get a closer look with the spacecraft Pioneer 10 and 11. The Voyager 1 and 2 spacecraft were launched with the specific purpose of collecting information and data on the Jovian worlds. In December 1995 the Galileo spacecraft entered into orbit and began it's long-term study of Jupiter and it's moons, a probe was also sent deep into the atmosphere of the gas giant.

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Selected radiation astronomy

Reds

Main articles: Radiation astronomy/Reds and Red astronomy

At left, Photograph of Jupiter's enormous Great Red Spot in 1879 from "A History of Astronomy in the 19th Century". Credit: Agnes Clerk and NASA.

The Great Red Spot (GRS) is a persistent anticyclonic storm, 22° south of Jupiter's equator, which has lasted for at least 194 years and possibly longer than 359 years. The storm is large enough to be visible through Draft:Earth-based telescopes. Its dimensions are 24–40,000 km west–to–east and 12–14,000 km south–to–north. The spot is large enough to contain two or three planets the size of Earth. At the start of 2004, the Great Red Spot had approximately half the longitudinal extent it had a century ago, when it was 40,000 km in diameter. The Great Red Spot's latitude has been stable for the duration of good observational records, typically varying by about a degree.

It is not known exactly what causes the Great Red Spot's reddish color. Theories supported by laboratory experiments suppose that the color may be caused by complex organic molecules, red phosphorus, or yet another sulfur compound. The Great Red Spot (GRS) varies greatly in hue, from almost brick-red to pale salmon, or even white. The reddest central region is slightly warmer than the surroundings, which is the first evidence that the Spot's color is affected by environmental factors. The spot occasionally disappears from the visible spectrum, becoming evident only through the Red Spot Hollow, which is its niche in the South Equatorial Belt. The visibility of GRS is apparently coupled to the appearance of the SEB; when the belt is bright white, the spot tends to be dark, and when it is dark, the spot is usually light. The periods when the spot is dark or light occur at irregular intervals; as of 1997, during the preceding 50 years, the spot was darkest in the periods 1961–66, 1968–75, 1989–90, and 1992–93.

"Jupiter’s most celebrated atmospheric beauty mark, the Great Red Spot (GRS), has been shrinking for years. When I was a kid in the ’60s peering through my Edmund 6-inch reflector, not only was the Spot decidedly red, but it was extremely easy to see. Back then it really did span three Earths."

"In the 1880s the GRS resembled a huge blimp gliding high above white crystalline clouds of ammonia and spanned 40,000 km (25, 000 miles) across. You couldn’t miss it even in those small brass refractors that were the standard amateur observing gear back in the day. Nearly one hundred years later in 1979, the Spot’s north-south extent has remained virtually unchanged, but it’s girth had shrunk to 25,000 km (15,535 miles) or just shy of two Earth diameters. Recent work done by expert astrophotographer Damian Peach using the WINJUPOS program to precisely measure the GRS in high resolution photos over the past 10 years indicates a continued steady shrinkage:" 2003 Feb – 18,420km (11,445 miles) 2005 Apr – 18,000km (11,184) 2010 Sep – 17,624km (10,951) 2013 Jan – 16,954km (10,534) 2013 Sep – 15,894km (9,876) 2013 Dec – 15,302km (9,508) = 1.2 Earth diameters.

"Not only has the Spot been shrinking, its rotation period has been speeding up. Older references give the period of one rotation at 6 days. John Rogers (British Astronomical Assn.) published a 2012 paper on the evolution of the GRS and discovered that between 2006 to 2012 – the same time as the Spot has been steadily shrinking – its rotation period has spun up to 4 days."

"Rogers also estimated a max wind speed of 300 mph, up from about 250 mph in 2006. Despite its smaller girth, this Jovian hurricane’s winds pack more punch than ever. Even more fascinating, the Great Red Spot may have even disappeared altogether from 1713 to 1830 before reappearing in 1831 as a long, pale “hollow”. According to Rogers, no observations or sketches of that era mention it. Surely something so prominent wouldn’t be missed. This begs the question of what happened in 1831. Was the “hollow” the genesis of a brand new Red Spot unrelated to the one first seen by astronomer Giovanni Cassini in 1665? Or was it the resurgence of Cassini’s Spot?"

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Selected topic

Trojan asteroids

Main articles: Rocks/Rocky objects/Asteroids/Trojans and Trojan asteroids

Diagram of Lagrange points is in a system where the primary is much more massive than the secondary. Credit: Cmglee.

Def. "the L4 and L5 Lagrange points of the Sun-Jupiter orbital configuration" are called the Trojan points.

Def. "an asteroid occupying the Trojan points of the Sun-Jupiter system" is called a Trojan asteroid.

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Selected astronomy

Aurora astronomy

This image of Jupiter shows concentrations of auroral X-rays near the north and south magnetic poles. The Chandra X-ray Observatory accumulated X-ray counts from Jupiter for its entire 10-hour rotation on December 18, 2000. Credit: NASA/CXC/SWRI/G.R.Gladstone et al.

Aurora at Jupiter's north pole is seen in ultraviolet light by the Hubble Space Telescope. Credit: John T. Clarke (U. Michigan), ESA, NASA.

The "image of Jupiter shows concentrations of auroral X-rays near the north and south magnetic poles." The Chandra X-ray Observatory accumulated X-ray counts from Jupiter for its entire 10-hour rotation on December 18, 2000. Note that X-rays from the entire globe of Jupiter are detected.

Second is an ultraviolet image of aurora at Jupiter's north pole by the Hubble Space Telescope.

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Selected deity

Zeus

Main article: Classical planets/Zeus

Zeus and his eagle are the statue. Credit: Marcus Cyron.{{free media}}

In the ancient Greek religion, Zeus (Ancient Greek is the "Father of Gods and men". He is the god of sky and thunder in Greek mythology. His Roman counterpart is Jupiter and Etruscan counterpart is Tinia. Zeus is the child of Cronus and Rhea, and the youngest of his siblings. In most traditions he is married to Hera, although, at the oracle of Dodona, his consort is Dione: according to the Iliad, he is the father of Aphrodite by Dione.

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Selected image

This image shows Jupiter's south pole, as seen by NASA's Juno spacecraft from an altitude of 32,000 miles (52,000 kilometers). Credit: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles.{{free media}}

Here is "Jupiter's south pole, as seen by NASA's Juno spacecraft from an altitude of 32,000 miles (52,000 kilometers). The oval features are cyclones, up to 600 miles (1,000 kilometers) in diameter. Multiple images taken with the JunoCam instrument on three separate orbits were combined to show all areas in daylight, enhanced color, and stereographic projection."

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Selected meteor

Meteors

Main articles: Radiation astronomy/Meteors and Meteor astronomy

Jupiter seems to be in a transition state between a luminous sun and an opaque world. Credit: Unknown.{{free media}}

Appearance of the sunspots on July 25 is between 1883 and 1884. Credit: Unknown.{{free media}}

"EVERYBODY who watched the sun with a telescope last summer must have wondered at the great belt of spots lying across the southern part of the disk during the last half of July. Several of the spots and groups were of extraordinary size, and their arrangement was very singular. When the belt extended completely across the sun, there was visible at one time almost every characteristic form that sun-spots present. There was the yawning black chasm with sharply defined yet ragged edges, vast enough to swallow up the whole earth, with room to spare, and surrounded by a regular penumbral border as evenly shaded as an artist could have made it; there was the double or triple spot whose black centers, though widely separated from one another, were tangled, as it were, in one twisted and torn veil of penumbra, or connected by long, shadowy bands; there was the monstrous spot of grotesque form surrounded by a crowd of smaller spots of even more fantastic shape, and enveloped in a broad, irregular penumbra as bizarre and wonderful as the mighty sun-chasms inclosed in it; there was the great spot, often of singular outline, accompanied outside its shadowy borders by one or more swarms of minute black specks pitting the white photosphere in the most extraordinary fashion; there was the huge group, visible even to the unassisted eye, and consisting of half a dozen or more large spots intermingled with smaller ones whose number seemed to defy counting, and enveloped in a penumbral cloak of becoming amplitude; there, near the edges of the disk, were the crinkling lines and heaped-up masses of faculæ, the mountainous hydrogen-flames which marked the places where the intensest solar action was going on—in short, there was a panorama in which every variety of sun-spot seemed to be passing in a gigantic procession across the disk. And what a procession it was!—long enough, nearly, to reach from the earth to the moon and back again three times!"

The appearance of Jupiter during sun flare activity is shown.

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Selected moon

Ganymede

Main articles: Rocks/Rocky objects/Ganymede and Ganymede

A true color image of Ganymede is acquired by the Galileo spacecraft on June 26, 1996. Credit: NASA/JPL.

This is global pictoral map of Ganymede. Credit: National Oceanic and Atmospheric Administration/USGS.

"If Ganymede rotated around the Sun rather than around Jupiter, it would be classified as a planet."

The Galilean Moons is a "name given to Jupiter's four largest moons, Io, Europa, Callisto & Ganymede. They were discovered independently by Galileo Galilei and Simon Marius."

"Ganymede has a very distinct surface with bright and dark regions. The surface includes mountains, valleys, craters and lava flows. The darker regions are more heavily littered with craters implying that those regions are older. The largest dark region is named Galileo Regio and is almost 2000 miles [3200 km] in diameter. The lighter regions display extensive series of troughs and ridges, thought to be a result of tectonic movement."

"A notable attribute of the craters on Ganymede is that they are not very deep and don’t have mountains around the edges of them as can normally be seen around craters on other moons and planets. The reason for this is that the crust of Ganymede is relatively soft and over a geological time frame has flattened out the extreme elevation changes."

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Selected theory

Jupiter systems

Main articles: Planets/Jupiter/Systems and Jupiter systems

"A definite color gradient is observed [in the small inner satellites of Jupiter], with the satellites closer to Jupiter being redder: the mean violet/green ratio (0.42/0.56 μm) decreases from Thebe to Metis. This ratio also is lower for the trailing sides of Thebe and Amalthea than for their leading sides."

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