| Risultati della ricerca nelle immagini - "Hubble" |
00-Aristarchus Crater-2005-29-a-full_jpg.jpg01 - Aristarchus Crater (and Plateau)109 visiteThe HST Advanced Camera for Surveys snapped this close-up view of the Aristarchus crater on Aug. 21, 2005. The crater is 26 miles (about 42 Km) in diameter and approx. 2 miles (such as about 3,2 Km) in depth and sits at the South-Western edge of the Aristarchus Plateau. The Plateau is well known for its rich array of geologic features, including a dense concentration of volcanic rilles (such as river and valley-like landforms that resulted from the collapse of lava tubes) and source vents.
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00-The Moon from HST.jpg00 - The Moon through the "Eyes" of the Hubble Space Telescope104 visite
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001-Ceres-alone.jpg1-Ceres from Hubble Space Telescope59 visiteNASA's Hubble Space Telescope took these images of the asteroid 1 Ceres over a 2-hour and 20-minute span, the time it takes the Texas-sized object to complete one quarter of a rotation. One day on Ceres lasts 9 hours.
Hubble snapped 267 images of Ceres as it watched the asteroid make more than one rotation. By observing the asteroid during a full rotation, astronomers confirmed that Ceres has a nearly round body like Earth's. Ceres' shape suggests that its interior is layered like those of terrestrial planets such as Earth. Ceres may have a rocky inner core, an icy mantle, and a thim, dusty, outer crust.
The "Bright Spot" that we see is a mistery: it is (obviously) brighter than its surroundings, but it is still very dark (very low albedo) reflecting only a small portion of Sunlight.
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002-Aristarchus-detailmgnf-2005-29-l-full_jpg.jpg02 - Aristarchus Crater (detail mgnf)114 visiteAristarchus is also one of the "youngest" craters of the Moon: in fact it probably formed between 100 and 900 MY ago only (!).
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004-Ceres.jpgMoments of 1-Ceres (1)54 visiteDa "NASA - Picture of the Day", del 21 Agosto 2006:"Is 1-Ceres an Asteroid or a Planet?
Although a trivial designation to some, the recent suggestion by the Planet Definition Committee of the International Astronomical Union would have 1-Ceres reclassified from Asteroid to Planet.
A change in taxonomy might lead to more notoriety for the frequently overlooked world. Ceres, at about 1000 Km across, is the largest object in the main Asteroid Belt between Mars and Jupiter. Under the newly proposed criteria, Ceres would qualify as a planet because it is nearly spherical and sufficiently distant from other planets. Pictured above is the best picture yet of Ceres, taken by the Hubble Space Telescope as part of a series of exposures ending in 2004 January. Currently, NASA's Dawn mission is scheduled to launch in 2007 June to explore Ceres and Vesta, regardless of their future designations".
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005-Ceres.jpgMoments of 1-Ceres (2)54 visiteFor 2 centuries it was the largest known rock in the Solar System. The Texas-sized asteroid Ceres, about 930 Km (about 580 miles) across, was the first asteroid ever detected. The space rock was identified in 1801 by astronomer Giuseppe Piazzi, a monk in Sicily and the founding director of the Palermo Astronomical Observatory. He noted over a few nights a shifting point in the sky that wasn't one of the planets, their moons or a star. Thus, he discovered the rock.
After discovering the asteroid, Piazzi was invited to join the Celestial Police, a group of 24 international astronomers looking for what they called "guest planets" between Mars and Jupiter. The Celestial Police noted that the spacing between planets was fairly regular, but that there was a large gap between Mars and Jupiter.
Soon other small bodies were discovered in that region (Pallas in 1802, Juno in 1804 and Vesta in 1807), so the Celestial Police concluded that not just one, but many minor planets had to exist in a Main Asteroid Belt.
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006-Ceres.jpg1-Ceres (natural colors, from HST - credits: NASA/ESA et al.)54 visiteThe Hubble image of Ceres on the reveals bright and dark regions on the asteroid's surface that could be topographic features, such as craters, and/or areas containing different surface material. Large impacts may have caused some of these features and potentially added new material to the landscape. The Texas-sized asteroid holds about 30 to 40% of the mass in the Asteroid Belt.
Ceres' round shape suggests that its interior is layered like those of terrestrial planets such as Earth. The asteroid may have a rocky inner core, an icy mantle, and a thin, dusty outer crust. The asteroid may even have water locked beneath its surface. It is approx. 590 miles (950 Km) across and was the first asteroid discovered in 1801.
The observation was made in visible and ultraviolet light between December 2003 and January 2004 with the HST Advanced Camera for Surveys. The color variations in the image show either a difference in texture or composition on Ceres' surface.
Astronomers need the close-up views of the Dawn spacecraft to determine the characteristics of these regional differences.
MareKromium
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015-Ceres_and_Vesta.jpg4-Vesta and 1-Ceres from HST (natural colors)54 visiteThese Hubble Space Telescope images of Vesta and 1-Ceres show two of the most massive asteroids in the Asteroid Belt, a Region between Mars and Jupiter.
The images are helping astronomers plan for the Dawn spacecraft’s tour of these hefty asteroids. On July 7, 2007, NASA is scheduled to launch the spacecraft on a 4-year journey to the Asteroid Belt. Once there, Dawn will do some asteroid-hopping, going into orbit around Vesta in 2011 and Ceres in 2015. Dawn will be the first spacecraft to orbit two targets. At least 100.000 asteroids inhabit the Asteroid Belt, a reservoir of leftover material from the formation of our Solar-System planets some 4,6 Billion Years (BY) ago.MareKromium
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021-Vesta-3.jpgMoments of 4-Vesta54 visiteTo prepare for the Dawn spacecraft's visit to Vesta, astronomers used Hubble's Wide Field Planetary Camera 2 to snap new images of the asteroid. These images were taken on May 14 and 16, 2007. Each frame shows time in hours and minutes based on Vesta's 5,34-hour rotation period. Using Hubble, astronomers mapped Vesta's Southern Hemisphere, a Region dominated by a giant impact crater formed by a collision billions of years ago. The crater is 285 miles (456 Km) across, which is nearly equal to Vesta's 330-mile (530-Km) diameter.
Hubble's sharp "eye" can see features as small as about 37 miles (60 Km) across. The images show the difference in brightness and color on the asteroid's surface. These characteristics hint at the large-scale features that the Dawn spacecraft will see when it arrives at Vesta in 2011.
Hubble's view reveals extensive global features stretching longitudinally from the Northern Hemisphere to the Southern Hemisphere.
The images also show widespread differences in brightness in the east and west, which probably reflects compositional changes. Both of these characteristics could reveal volcanic activity throughout Vesta. The size of these different regions varies. Some are hundreds of miles across.
The brightness differences could be similar to the effect seen on the Moon, where smooth, dark regions are more iron-rich than the brighter highlands that contain minerals richer in calcium and aluminum. When Vesta was forming 4.5 billion years ago, it was heated to the melting temperatures of rock. This heating allowed heavier material to sink to Vesta's center and lighter minerals to rise to the surface.
Astronomers combined images of Vesta in two colors to study the variations in iron-bearing minerals. From these minerals, they hope to learn more about Vesta's surface structure and composition. Astronomers expect that Dawn will provide rich details about the asteroid's surface and interior structure.
MareKromium
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05-Copernicus-HST.jpg05 - Copernicus Crater120 visite
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20-Apollo17LS-2005-29-f-full_jpg.jpg20 - The Apollo 17 Landing Site120 visite
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21-Apollo17-LS-2005-29-m-full_jpg.jpg21 - The Apollo 17 Landing Site148 visite
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