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| Piú votate - Pluto and Charon: The "Double Planet" |
ZZ-ZZ-ZZ-ZZ-20100727_LORRINeptune_lg.jpgOn the Way to Pluto: Neptune's on sight!79 visiteCaption NASA:"The New Horizons Long Range Reconnaissance Imager (LORRI) observed Neptune on June 23, 2010, as part of a test of the critical Optical Navigation Annual Checkout (ACO).
In this 100-millisecond exposure, taken when the Spacecraft was 23,2 Astronomical Units (about 2,15 Billion Miles) from Neptune, the Planet appears slightly larger than a star. At the time of this observation, the Solar Phase Angle was 34° and the Solar Elongation Angle (Planet-Spacecraft-Sun) was 95°.
Only New Horizons can observe Neptune at such large Solar Phase Angles, which can be used to study the light-scattering properties of Neptune's Atmosphere".MareKromium
(5 voti)
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Pluto-421596main_s1006ay-2.jpgSurface Color-Variations on Pluto58 visiteNASA today released the most detailed set of images ever taken of the distant dwarf planet Pluto. The images taken by NASA's Hubble Space Telescope show an icy and dark molasses-colored, mottled world that is undergoing seasonal changes in its surface color and brightness. Pluto has become significantly redder, while its illuminated Northern Hemisphere is getting brighter. These changes are most likely consequences of surface ices sublimating on the sunlit Pole and then refreezing on the other Pole as the dwarf planet heads into the next phase of its 248-year-long seasonal cycle. The dramatic change in color apparently took place in a two-year period, from 2000 to 2002.
The Hubble images will remain our sharpest view of Pluto until NASA's New Horizons probe is within 6 months of its Pluto flyby. The Hubble pictures are proving invaluable for picking out the planet's most interesting-looking hemisphere for the New Horizons spacecraft to swoop over when it flies by Pluto in 2015.
Though Pluto is arguably one of the public's favorite planetary objects, it is also the hardest of which to get a detailed portrait because the world is small and very far away. Hubble resolves surface variations a few hundred miles across, which are too coarse for understanding Surface Geology. But in terms of surface color and brightness Hubble reveals a complex-looking and variegated world with white, dark-orange, and charcoal-black terrain. The overall color is believed to be a result of UltraViolet radiation from the distant Sun breaking up Methane that is present on Pluto's Surface, leaving behind a dark and red carbon-rich residue.
When Hubble pictures taken in 1994 are compared with a new set of images taken in 2002 to 2003, astronomers see evidence that the northern polar region has gotten brighter, while the southern hemisphere has gotten darker. These changes hint at very complex processes affecting the visible surface, and the new data will be used in continued research.
The images are allowing planetary astronomers to better interpret more than three decades of Pluto observations from other telescopes, says principal investigator Marc Buie of the Southwest Research Institute in Boulder, Colo. "The Hubble observations are the key to tying together these other diverse constraints on Pluto and showing how it all makes sense by providing a context based on weather and seasonal changes, which opens other new lines of investigation."
The Hubble pictures underscore that Pluto is not simply a ball of ice and rock but a dynamic world that undergoes dramatic atmospheric changes. These are driven by seasonal changes that are as much propelled by the Planet's 248-year elliptical orbit as its axial tilt, unlike Earth where the tilt alone drives seasons. The seasons are very asymmetric because of Pluto's elliptical orbit. Spring transitions to Polar Summer quickly in the Northern Hemisphere because Pluto is moving faster along its orbit when it is closer to the Sun.
Ground-based observations, taken in 1988 and 2002, show that the mass of the atmosphere doubled over that time. This may be due to warming and sublimating Nitrogen ice. The new Hubble images from 2002 to 2003 are giving astronomers essential clues about how the seasons on Pluto work and about the fate of its atmosphere.
The images, taken by the Advanced Camera for Surveys, are invaluable to planning the details of the New Horizons flyby in 2015. New Horizons will pass by Pluto so quickly that only one hemisphere will be photographed in the highest possible detail. Particularly noticeable in the Hubble image is a bright spot that has been independently noted to be unusually rich in carbon monoxide frost. It is a prime target for New Horizons. "Everybody is puzzled by this feature," says Buie. New Horizons will get an excellent look at the boundary between this bright feature and a nearby region covered in pitch-black surface material.
"The Hubble images will also help New Horizons scientists better calculate the exposure time for each Pluto snapshot, which is important for taking the most detailed pictures possible," says Buie. With no chance for re-exposures, accurate models for the surface of Pluto are essential in preventing pictures that are either under- or overexposed.
The Hubble images are a few pixels wide. But through a technique called dithering, multiple, slightly offset pictures can be combined through computer-image processing to synthesize a higher-resolution view than could be seen in a single exposure. "This has taken four years and 20 computers operating continuously and simultaneously to accomplish," says Buie, who developed special algorithms to sharpen the Hubble data.
The Hubble research results appear in the March 2010 issue of the Astronomical Journal. Buie's science team members are William Grundy of Lowell Observatory in Flagstaff, Ariz., and Eliot Young, Leslie Young, and Alan Stern of Southwest Research Institute in Boulder, Colo.
Buie plans to use Hubble's new Wide Field Camera 3 to make further Pluto observations prior to the arrival of New Horizons.MareKromium
(5 voti)
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B-Caron.jpgThe Discovey of Charon55 visiteCharon was discovered in June 1978 by U.S. Naval Observatory astronomers James Christy and Robert Harrington. They weren't even looking for satellites of Pluto - they were trying to refine Pluto's orbit around the Sun!
Charon was discovered when sharp-eyed Christy noticed the images of Pluto were strangely elongated - it looked like Pluto had an irregular blob attached to its side. Perhaps the telescope was joggled when the picture was taken? No, that possibility was quickly eliminated by noticing that the other stars on the photo were round. Moreover, the blob itself seemed to move around Pluto - the direction of elongation cycled back and forth over 6.39 days - Pluto's rotation period. From this, Christy, after being checked by Harrington, concluded that Pluto either possessed a mountain thousands of kilometers high or a satellite that orbited in its synchronous orbit.
Searching through their archives of Pluto images taken years before, Christy found more cases where Pluto appeared strangely elongated. Working independently, Christy measured the angle (from north) where the elongations appeared while Harrington calculated what the answer "should be" if the elongation was caused by an orbiting satellite. When the anxious moment came for them to compare their answers, they found perfect agreement. Just to be sure, they waited for the U. S. Naval Observatory 60-inch telescope to make one more confirmation. And sure enough, on July 2 new images showed the elongation due to a satellite right where it was supposed to be. They announced their discovery to the world on July 7, 1978. Christy proposed the name "Charon", after the mythological ferryman who carried souls across the river Acheron, one of the five mythical rivers that surrounded Pluto's underworld. Apart from the mythological connection for this name, Christy chose it because the first four letters also matched the name of his wife, Charlene.
Charon's satellite status was finally confirmed when Pluto and Charon began a series of mutual eclipses in 1985. Later, Hubble Space Telescope and even advanced ground-based telescopes were able to spot Charon orbiting nearby — just 1/4000th of a degree from Pluto!MareKromium
(5 voti)
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ZYZ-R-Pluto.jpgPluto54 visitenessun commento
(5 voti)
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ZJ-Charon.gifCharon (the surface - speculation)56 visiteOriginal caption:"This image shows 4 views of Pluto's moon Charon.
The images are centered in 0° Lat. and 0° (top-left), 90° (top-right), 180° (bottom-left) and 270° (bottom-right) Long.
The images are based on photometric measurements of Marc Bouie/Lowell Observatory".
(5 voti)
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ZK-CharonMap.jpgThe surface of Charon (speculation)55 visiteOriginal caption:"This is the first surface map of Charon, the moon of the Solar System's most remote planet, Pluto. The map is only based on photometric measurements and it covers the entire surface of the moon. (Courtesy A.Tayfun Oner, based on pictures courtesy of Marc Buie/Lowell Observatory)
(5 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-Pluto-nh_01_stern_05_pluto_hazenew-PCF-LXTT-IPF-00.jpgPlutonian Night89 visitenessun commentoMareKromium
(4 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-Pluto-PIA19948-PCF-LXTT-IPF.jpg15 Minutes after Pluto - Large View (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)65 visiteJust 15 minutes after its Closest Approach to Pluto - which occurred on July, 14, 2015 -, the NASA - New Horizons Spacecraft looked back toward the Sun and captured this simply beautiful Near-Sunset View of the rugged, Icy Mountains and flat Ice Plains extending all over around and to Pluto's Horizon and Terminator Line.
The smooth expanse of the Icy Plains which have (so far) been informally named Sputnik Planum (watch to the right - Dx - of the picture) is flanked to the West (left - Sx) by rugged Mountains that reach up an altitude of approx. 11.000 feet (such as, roughly, 3352,8 meters), including the (even in this case, so far) informally named Norgay Montes (visible in the foreground) and the Hillary Montes, visible on the Skyline (---> Outer Edge/Horizon of Pluto). To the right (Dx), such as to the East of Sputnik Planum, some rougher (---> highly irregular) Terrain is cut by - what they appear to be - Glaciers. Furthermore, the backlighting, highlights several Layers of Haze in Pluto's tenuous - but quite uniform and highly distended - Atmosphere.
This image was taken from a distance of about 11.000 miles (such as approx. 17.702,74 Km) from the Surface of Pluto; finally, the whole scene is roughly 780 miles (about 1.255,2852 Km) wide.
The image (which is an Original NASA - New Horizons Spacecraft's b/w and NON Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. 19948) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized (according to an educated guess carried out by Dr Paolo C. Fienga-LXTT-IPF) in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - New Horizons Spacecraft and then looked outside, towards the Dwarf-Planet Pluto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(4 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-Pluto-PIA19936-PCF-LXTT-IPF.jpgSputnik Planum and Surroundings (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 63 visiteThis beautiful picture is, in fact, an Image-Mosaic which has been created by using (---> putting together) several High-Resolution frames of the Dwarf-Planet Pluto, that were all sent back to Earth by the NASA - New Horizons Spacecraft in the days going from September 5 to 7, 2015. The mosaic, as you can easily see, is dominated by the bright Icy Plains which have (so far) been informally named Sputnik Planum.
However, the Image-Mosaic also features (---> shows) a tremendous variety of other (and, Geologically speaking, completely different) Landscapes that surrounds Sputnik Planum (---> such as a number of areas of Pluto which we have already shown you in the APODs of Semptember 14, 15 and 16, 2015).
The smallest visible Surface Features here are roughly 0,5 miles (such as approx. 0,80467 Km) across, and the Mosaic - in its entirety - covers a Plutonian Region that is about 1000 miles (such as, roughly, 1609,34 Km) wide. The images forming the Mosaic were taken as the NASA - New Horizons Spacecraft flew past Pluto on July 14, 2015, from a distance of about 50.000 miles (such as approx. 80.467 Km).
The image (which is an Original NASA - New Horizons Spacecraft's b/w and NON Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 19936) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized (according to an educated guess carried out by Dr Paolo C. Fienga-LXTT-IPF) in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - New Horizons Spacecraft and then looked ahead, towards the Dwarf-Planet Pluto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(4 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-Pluto-PIA19937-PCF-LXTT-IPF.jpgSputnik Planum (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 78 visiteThis Synthetic Perspective view of Pluto, based on the latest High-Resolution images to be downlinked from the NASA - New Horizons Spacecraft, shows us what you would see if you were approximately 1100 miles (such as about 1770,284 Km) above Pluto's Equatorial Area, looking North/East - over the dark/orangish and heavily cratered Region informally named Cthulhu Regio - toward the bright, smooth, expanse of Icy Plains which have, for now, been informally called Sputnik Planum.
The entire expanse of Terrain seen in this image is roughly 1100 miles (such as about 1770,284 Km ) across. The images were taken as the NASA - New Horizons Spacecraft flew past Pluto on July 14, 2015, from a distance of about 50.000 miles (such as approx. 80.467 Km).
The image (which is an Original NASA - New Horizons Spacecraft's b/w and NON Map-Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 19937) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then colorized (according to an educated guess carried out by Dr Paolo C. Fienga-LXTT-IPF) in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - New Horizons Spacecraft and then looked ahead, towards the Dwarf-Planet Pluto), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(4 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-ZZ-Charon-PIA19709-PCF-LXTT-IPF.jpgCharon (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)86 visiteRemarkable new details of Pluto's largest moon Charon are revealed in this wonderful image from New Horizons' Long Range Reconnaissance Imager (or "LORRI", for short), that was taken late on July 13, 2015, from a distance of about 289.000 miles (such as approx. 465.099,26 Km). A swath of Cliffs and Troughs stretches about 600 miles (approx. 1609,34 Km) from left (Sx) to right (Dx), suggesting the occurrence, in a remote past, of a widespread fracturing of Charon's Crust (likely a result of internal processes). At the upper righ (Dx) of the framet, along the moon's curving edge, there is a Canyon that is estimated to be approx. 4 to 6 miles (such as about 6,437 to roughly 9,656 Km) deep.
The Mission Scientists are surprised by the apparent lack of Impact Craters on Charon. South of the moon's Equator, at the bottom of this image, Terrain is lit by the slanting Rays of the Sun, and thus creating shadows that make it easier to distinguish its real Topography. Even here, however, relatively few Impact Craters are visible, and this circumstance indicates a (relatively speaking) young Surface that, probably, has been often reshaped by Geologic Activites.
In Charon's North Polar Regions, a dark marking - which was already prominent in the NASA - New Horizons Spacecraft' approach images - is now seen to have a diffuse (---> lighter in color) Boundary, suggesting that it could be a thin Deposit of Dark Material. Underlying, it is a distinct, sharply bounded, Angular Surface Feature; higher resolution images still to come are expected to shed more light on this truly enigmatic Region.
The image (which is an Original NASA - New Horizons Spacecraft's falsely colored and NON Map-Projected frame published on the NASA - Planetary Phojournal with the ID n. 19709) has been additionally processed, magnified to aid the visibility of the details, contrast enhanced and sharpened, Gamma corrected and then re-colorized (according to an educated guess carried out by Dr Paolo C. Fienga-LXTT-IPF) in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - New Horizons Spacecraft and then looked ahead, towards the Plutonian moon Charon), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.MareKromium
(4 voti)
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ZZ-ZZ-ZZ-ZZ-ZZ-20110401_0515.jpgWhere's New Horizons? April 2011 (1) - Current Position (beyond Uranus' Orbit)120 visiteThis image shows New Horizons' "Current Position". The green segment of the line shows where New Horizons has traveled since launch; the red indicates the Spacecraft's path toward Jupiter, Pluto and beyond. Positions of stars with magnitude 12 or brighter are shown from this perspective, which is above the Sun and "north" of Earth's orbit.
Notes: what Is an AU? The graphics on these pages note New Horizons' distance from Earth, Jupiter and Pluto in AU, or Astronomical Units. One AU is the average distance between the Sun and Earth, such as about 93 Million Miles (MMs) or 149,6 Million Kilometers (MKM).
Heliocentric Velocity. The Current Position graphic also notes the Spacecraft's "Heliocentric Velocity" - such as its speed with respect to the Sun - in Kilometers per second (Km/sec). One Km/sec is equivalent to 0,62 miles per second (Mi/sec), or 2237 miles per hour (mph).
New Horizons crossed the orbit of Uranus at approximately 18:00 EDT on March 18, 2011, with the Spacecraft more than 1,8 Billion Miles (nearly 2,9 Billion Kilometers) from Earth. Uranus was 2,4 BMs (3,8 BKM) from New Horizons at the time and the Spacecraft was cruising in "Electronic Sleep Mode".MareKromium
(4 voti)
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