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Jupiter: the "King" and His Moons
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JupiterSystem-050107_09.jpgThe "Galilean Family" of Jupiter86 visiteThis montage shows the best views of Jupiter's four large and diverse "Galilean" satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter.
Io, 3,640 kilometers (2,260 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.7 million kilometers (1.7 million miles). The original image scale was 13 kilometers per pixel, and the image is centered at Io coordinates 6 degrees south, 22 degrees west. Io is notable for its active volcanism, which New Horizons has studied extensively.
Europa, 3,120 kilometers (1,938 miles) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 3 million kilometers (1.8 million miles). The original image scale was 15 kilometers per pixel, and the image is centered at Europa coordinates 6 degrees south, 347 degrees west. Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa’s surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it.
New Horizons spied Ganymede, 5,262 kilometers (3,268 miles) in diameter, at 10:01 Universal Time on February 27 from 3.5 million kilometers (2.2 million miles) away. The original scale was 17 kilometers per pixel, and the image is centered at Ganymede coordinates 6 degrees south, 38 degrees west. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons’ infrared observations may provide insight into the composition of the moon’s surface and interior.
Callisto, 4,820 kilometers (2,995 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 4.2 million kilometers (2.6 million miles). The original image scale was 21 kilometers per pixel, and the image is centered at Callisto coordinates 4 degrees south, 356 degrees west. Scientists are using the infrared spectra New Horizons gathered of Callisto’s ancient, cratered surface to calibrate spectral analysis techniques that will help them to understand the surfaces of Pluto and its moon Charon when New Horizons passes them in 2015.
MareKromium
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Jupiter_Io-PIA10102.jpgLike Father and Son... (approx. true colors; credits: NASA)77 visiteCaption NASA:"This is a montage of New Horizons images of Jupiter and its volcanic moon Io, taken during the Spacecraft's Jupiter flyby in early 2007. The Jupiter image is an infrared color composite taken by the spacecraft's near-infrared imaging spectrometer, the Linear Etalon Imaging Spectral Array (LEISA) at 1:40 UT on Feb. 28, 2007. The infrared wavelengths used (red: 1.59 µm, green: 1.94 µm, blue: 1.85 µm) highlight variations in the altitude of the Jovian cloud tops, with blue denoting high-altitude clouds and hazes, and red indicating deeper clouds. The prominent bluish-white oval is the Great Red Spot. The observation was made at a solar phase angle of 75° but has been projected onto a crescent to remove distortion caused by Jupiter's rotation during the scan.
The Io image, taken at 00:25 UT on March 1st 2007, is an approx. true-color composite taken by the panchromatic Long-Range Reconnaissance Imager (LORRI), with color information provided by the 0.5 µm ("blue") and 0.9 µm ("methane") channelsof the Multispectral Visible Imaging Camera (MVIC). The image shows a major eruption in progress on Io's night side, at the northern volcano Tvashtar. Incandescent lava glows red beneath a 330-kilometer high volcanic plume, whose uppermost portions are illuminated by sunlight. The plume appears blue due to scattering of light by small particles in the plume ".MareKromium
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Jupiter_JUNO.gifUp, Down, like a Yo-Yo!88 visitenessun commentoMareKromium
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Jupiter_Storm.jpgThe Dark S.E.B. of Jupiter is back!82 visiteDalla Rubrica "NASA - Picture of the Day" del giorno 29 Npvembre 2010:"Why are planet-circling clouds disappearing and reappearing on Jupiter?
Although the ultimate cause remains unknown, planetary meteorologists are beginning to better understand what is happening. Earlier this year, unexpectedly, Jupiter's Dark Southern Equatorial Belt (SEB) disappeared. The changes were first noted by amateurs dedicated to watching Jupiter full time. The South Equatorial Band has been seen to change colors before, although the change has never been recorded in such detail. Detailed professional observations revealed that high-flying light-colored Ammonia-based clouds formed over the planet-circling Dark Belt. Now those Light Clouds are dissipating, again unveiling the lower Dark Clouds.
Pictured above two weeks ago, far InfraRed images - depicted in false-color red - show a powerful storm system active above the returning Dark Belt. Continued observations of Jupiter's current cloud opera, and our understanding of it, is sure to continue".MareKromium
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Jupiter_from_New_Horizons-092606_1_hr.jpgJupiter, from New Horizons69 visiteBlazing along its path to Pluto, NASA's New Horizons has come within hailing distance of Jupiter. The first picture of the Giant Planet from the spacecraft's Long Range Reconnaissance Imager (LORRI), taken Sept. 4, 2006, is a tantalizing promise of what's to come when New Horizons flies through the Jupiter system early next year.
New Horizons was still 291 MKM (nearly 181 MMs) away from Jupiter when LORRI took the photo.
As New Horizons comes much closer, next January and February 2007, LORRI will take more-detailed images.
"These first LORRI images of Jupiter are awe-inspiring," says New Horizons Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory (APL), where LORRI was designed and built. "New Horizons is speeding toward this majestic planet at 45,000 miles per hour, right on target for a close encounter on February 28 of next year. LORRI's resolution at Jupiter will be 125 times better than now, and we're really looking forward to getting the most detailed views of the Jovian system since Cassini's flyby in late 2000 and Galileo's final images in 2003."
Now on the outskirts of the asteroid belt, LORRI snapped this image during a test sequence to help prepare for the Jupiter encounter observations. It was taken close to solar opposition, meaning that the Sun was almost directly behind the camera when it spied Jupiter. This makes Jupiter appear blindingly bright, about 40 times brighter than Pluto will be for LORRI's primary observations when New Horizons encounters the Pluto system in 2015. To avoid saturation, the camera's exposure time was kept to 6 milliseconds. This image was, in part, a test to see how well LORRI would operate with such a short exposure time.
"LORRI's first Jupiter image is all we could have expected," says LORRI Principal Investigator Andy Cheng, of APL. "We see belts, zones and large storms in Jupiter's atmosphere. We see the Jovian moons Io and Europa, as well as the shadows they cast on Jupiter. It is most gratifying to detect these moons against the glare from Jupiter."
LORRI wasn't the only New Horizons instrument peeking at Jupiter on Sept. 4; the Ralph imager also performed some important calibrations. "We rapidly scanned Ralph's Multispectral Visible Imaging Camera [MVIC] across Jupiter to test a technique we plan to employ near closest approach next February. We also observed Jupiter in the infrared using Ralph's Linear Etalon Imaging Spectral Array [LEISA]," says Ralph Program Manager Cathy Olkin, of the Southwest Research Institute. "Everything worked great."
New Horizons won't observe Jupiter again until early January 2007, when periodic monitoring will begin, followed by intensive observations at the end of February. The spacecraft will also continue to look at the Jovian magnetosphere for several months after closest approach.
"New Horizons is headed to a spectacular science encounter with the Jupiter system early next year," says mission Principal Investigator Alan Stern, of the Southwest Research Institute. "The first LORRI images of Jupiter just whet our appetite for the observations to come."
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Jupiter_s Aurora-HST-PIA03155_modest.jpgJupiter's Aurora - HST74 visiteCaption NASA originale:"Auroras are curtains of light resulting from high-energy electrons racing along the planet's magnetic field into the upper atmosphere.
The electrons excite atmospheric gases, causing them to glow.
The image shows the main oval of the aurora, which is centered on the magnetic north pole, plus more diffuse emissions inside the polar cap. The HST image shows also unique emissions from the magnetic "footprints" of 3 of Jupiter's largest moons.
Auroral footprints can be seen in this image from Io (along the lefthand limb), Ganymede (near the center), and Europa (just below and to the right of Ganymede's auroral footprint).
These emissions, produced by electric currents generated by the satellites, flow along Jupiter's magnetic field, bouncing in and out of the upper atmosphere".
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Jupiter_s New Spot.jpgThe "New Red Spot" of Jupiter63 visiteJupiter's "Great Red Spot" is a swirling storm seen for over 300 years, since the begining of telescopic observations of the Solar System's ruling gas giant. But over the last month, the Great Red Spot has been joined by a new one (informally named "Red Spot Jr."). Thought to be similar to the Great Red Spot itself, this smaller Red Spot was actually seen to form as smaller whitish oval-shaped storms merged and then developed the remarkable reddish hue. This webcam image showing the two red tinted Jovian storms was recorded on the morning of March 12, 2006, from the Central Coast of New South Wales, Australia - part of a series showing Jupiter's rotation. Similar in diameter to planet Earth, Red Spot Jr. is expected to last for a while and trails the Great Red Spot by about an hour as the Planet rotates. Astronomers still don't exactly understand why Jupiter's red spots...are red.
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Jupiter_s NorthPole-PIA07783.jpgThe North Pole of Jupiter71 visiteThe South Polar Regions shown here are less clearly visible because Cassini viewed them at an angle and through thicker atmospheric haze.
The round maps are polar stereographic projections that show the North or South Pole in the center of the map and the Equator at the edge.
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Jupiter_s Rings-PIA01529_modest.jpgColorful Jupiter's Rings825 visiteCaption NASA originale:"Jupiter's faint ring system is shown in this color composite as two light orange lines protruding from the left toward Jupiter's limb. This picture was taken in Jupiter's shadow through orange and violet filters. The colorful images of Jupiter's bright limb are evidence of the spacecraft motion during these long exposures. The Voyager 2 spacecraft was at a range of 1.450.000 kilometers about two degrees below the plane of the ring. The lower ring image was cut short by Jupiter's shadow on the ring itself".
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Jupiter_s Rings-PIA01627.jpgThe Rings of Jupiter (1)53 visiteOriginal caption:"This schematic cut-away view of the components of Jupiter's Ring System shows the geometry of the Rings in relation to Jupiter and to the small inner moons, which are the source of the dust forming the Rings themselves. The innermost and thickest Ring, shown in gray shading, is the halo that ends at the Main Ring. The thin, narrow Main Ring, shown with red shading, is bounded by the 16- Km-wide (10-miles) satellite Adrastea and shows a marked decrease in brightness near the orbit of Jupiter's innermost moon, Metis. It is composed of fine particles knocked off Adrastea and Metis. Although the orbits of Adrastea and Metis are about 1000 Km (about 600 miles) apart, that separation is not depicted in this drawing. Impacts by small meteoroids (fragments of asteroids and comets) into these small, low-gravity satellites feed material into the Rings. Thebe and Amalthea, the next 2 moons in increasing distance from Jupiter, supply dust which forms the thicker, disk-like 'Gossamer' Rings".
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Jupiter_s Rings-PIA01628.jpgThe Rings of Jupiter (2)53 visiteScientists studying data from Galileo spacecraft have found that the Ring System is made up of impact debris created when meteoroids, which are fragments of comets and asteroids, slam into Jupiter`s four smallest satellites. The top panel shows that the Main Ring (red) is formed mostly from meteoroid impact debris kicked up from the innermost moons, Metis (m) and Adrastea (a). Since both satellites orbit in paths not inclined to Jupiter's equator, the Main Ring appears as a narrow line. The middle panel shows the additional effect of dust ejected from the satellite Amalthea (A), responsible for producing 1 of the 2 moon components of the Gossamer Ring. Amalthea's orbit is inclined to Jupiter's equatorial plane and at different times the satellite's vertical position can range anywhere between the 2 extreme limits shown. Dust ejected from Amalthea (orange) produces a ring whose thickness equals Amalthea's vertical projections beyond Jupiter's equatorial plane. The lower panel shows the additional effect of dust ejected from Thebe (T), which makes up the second component (shown in green) of the gossamer ring. Again, the two positions shown represent the maximum projections of Thebe from Jupiter's equatorial plane. This component of the gossamer ring is thicker than the component due to Amaltheas dust because Thebe's orbit is more inclined than that of Amalthea.
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Jupiter_s SouthPole-PIA07784.jpgThe South Pole of Jupiter53 visiteThe South Polar Regions shown here are less clearly visible because Cassini viewed them at an angle and through thicker atmospheric haze.
The round maps are polar stereographic projections that show the North or South Pole in the center of the map and the Equator at the edge.
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