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Gaspra-Deimos-Phobos-PIA00078_modest.jpgGaspra, Deimos and Phobos56 visiteCaption NASA originale:"This montage shows asteroid 951 Gaspra (top) compared with Deimos (lower left) and Phobos (lower right), the moons of Mars. The three bodies are shown at the same scale and nearly the same lighting conditions. Gaspra is about 17 Km (10 miles) long. All three bodies have irregular shapes, due to past catastrophic conditions. However their surfaces appear remarkably different, possibly because of differences in composition but most likely because of very different impact histories. The Phobos and Deimos images were obtained by the Viking Orbiter spacecraft in 1977; the Gaspra image is the best of a series obtained by the Galileo spacecraft on October 29, 1991".
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Haumea-1.jpgHaumea: an "Egg" in the Outer Solar System...78 visitenessun commentoMareKromium
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Haumea2.jpgHaumea and other "Dwarf" Companions54 visiteCaption NASA:"One of the strangest objects in the Outer Solar System was classified as a Dwarf Planet last week (September 2008) and given the name Haumea.
This designation makes Haumea the 5th designated Dwarf Planet after Pluto, Ceres, Eris, and Makemake. Haumea's smooth but oblong shape make it extremely unusual. Along one direction, Haumea is significantly longer than Pluto, while in another direction Haumea has an extent very similar to Pluto, while in the third direction is much smaller.
Haumea's orbit sometimes brings it closer to the Sun than Pluto, but usually Haumea is further away.
Illustrated above, an artist visualizes Haumea as a nearly featureless ellipsoid. Quite possibly, however, Haumea has interesting craters and surface features that currently remain unknown. Originally discovered in 2003 and given the temporary designation of 2003 EL61, Haumea was recently renamed by the IAU for a Hawaiian goddess. Haumea has two small moons discovered in 2005, recently renamed Hi'iaka and Namaka after the daughters of the Goddess".MareKromium
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Hycean_Planet.jpgThe "Hycean Planets"90 visite(ANSA) - Milano, 26 Agosto – Identificata una nuova classe di pianeti potenzialmente abitabili al di fuori del Sistema solare: caldi, ricoperti da oceani e con un'atmosfera ricca di Idrogeno, i quali potrebbero ospitare microrganismi adatti a vivere in condizioni estreme. La scoperta è pubblicata su The Astrophysical Journal dai ricercatori dell'Università di Cambridge, che hanno chiamato questi mondi alieni 'Hycean Planets': più numerosi e meglio osservabili degli esopianeti di tipo terrestre, potrebbe accelerare la ricerca di tracce di vita portando ad avere le prime risposte già nel giro di due o tre anni. Questi nuovi esopianeti possono essere fino a 2,6 volte più grandi della Terra e possono avere temperatura atmosferiche che arrivano ai 200°: nonostante ciò presentano grandi oceani che potrebbero supportare forme di vita microbica simili ai batteri estremi che vivono sulla Terra. Inoltre hanno una zona abitabile molto più ampia rispetto agli esopianeti terrestri: ciò significa che possono ospitare la vita anche se orbitano intorno alla loro stella a distanze diverse rispetto a quelle considerate vincolanti affinché un pianeta terrestre possa presentare acqua liquida in superficie.
I ricercatori di Cambridge hanno già selezionato un numero consistente di potenziali 'Hycean Planets' che saranno i primi candidati per le osservazioni con i telescopi di nuova generazione, come il James Webb Space Telescope che sarà lanciato entro l'anno.MareKromium
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IDA&DACTYL-PIA00333.jpgIda and Dactyl in "natural colors"67 visiteThis color picture is made from images taken by the imaging system on the Galileo spacecraft about 14 minutes before its closest approach to asteroid 243 Ida on August 28, 1993. The range from the spacecraft was about 10,500 kilometers (6,500 miles). The images used are from the sequence in which Ida's moon was originally discovered; the moon is visible to the right of the asteroid. This picture is made from images through the 4100-angstrom (violet), 7560 A (infrared) and 9680 A (infrared) filters. The color is 'enhanced' in the sense that the CCD camera is sensitive to near infrared wavelengths of light beyond human vision; a 'natural' color picture of this asteroid would appear mostly gray. Shadings in the image indicate changes in illumination angle on the many steep slopes of this irregular body as well as subtle color variations due to differences in the physical state and composition of the soil (regolith).
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IDA-PIA00135.jpgAsteroid Ida (HR)56 visiteThis view of the asteroid 243 Ida is a mosaic of 5 image frames acquired by the Galileo spacecraft's solid-state imaging system at ranges of 3.057 to 3.821 Km on August 28, 1993, about 3-1/2 minutes before the spacecraft made its closest approach to the asteroid. Galileo flew about 2.400 Km from Ida at a relative velocity of 12.4 km/sec (28,000 mph). Asteroid and spacecraft were 441 million Km from the Sun. Ida is the second asteroid ever encountered by a spacecraft. It appears to be about 52 Km in length, more than twice as large as Gaspra, the first asteroid observed by Galileo in October 1991. Ida is an irregularly shaped asteroid placed by scientists in the S class (believed to be like stony or stony iron meteorites). It is a member of the Koronis family, presumed fragments left from the breakup of a precursor asteroid in a catastrophic collision. This view shows numerous craters, including many degraded craters larger than any seen on Gaspra.
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IDA-PIA00138.jpgAsteroid Ida's limb (HR)66 visiteThe Galileo imaging system captured this picture of the limb of the asteroid 243 Ida about 46 seconds after its closest approach on August 28, 1993, from a range of only 2480 Km. It is the highest-resolution image of an asteroid's surface ever captured and shows detail at a scale of about 25 meters per pixel. This image is one frame of a mosaic of 15 frames shuttered near Galileo's closest approach to Ida. Since the exact location of Ida in space was not well-known prior to the Galileo flyby, this mosaic was estimated to have only about a 50 percent chance of capturing Ida. Fortunately, this single frame did successfully image a part of the sunlit side of Ida. The area seen in this frame shows some of the same territory seen in a slightly lower resolution full disk mosaic of Ida returned from the spacecraft in September, 1993, but from a different perspective. Prominent in this view is a 2 Km deep "valley" seen in profile on the limb.
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Ida-MF-LXTT.jpgAsteroid "Ida" (possible Natural Colors; credits for the additional process. and color.: Dr Marco Faccin - Lunexit Team)76 visitenessun commentoMareKromium
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Itokawa-03.pngThe Southern Hemisphere of Itokawa55 visiteAfter reaching the sub-solar point, Hayabusa started to travel out of the ecliptic plane to observe the polar regions of Itokawa. This image shows the Southern Hemisphere
of Itokawa. Due to the low altitude and solar elevation angles, we can see detailed topography in the high-latitude regions. There are even some boulders on Muses-Sea, which looked very smooth in previous observations. Imagine one of these boulders flying in space. If it came to the Earth's vicinity, we would observe it as a tiny independent near-Earth asteroid. It has long been conjectured that meteorites are fragments of asteroids delivered to the Earth's surface, but it remains to be proven. The samples of Itokawa collected and returned by Hayabusa could provide the first direct evidence of the link between asteroids and meteorites.
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Itokawa-04.jpgOrbiting around Itokawa (1)55 visiteHayabusa arrived at its exploration target, near Earth asteroid Itokawa, on Sept., 12th, 2005 after having been propelled there via ion engines and an Earth swing-by. Since then, it has successfully performed orbital maneuvers, precisely keeping its position relative to Itokawa. The Hayabusa Project Team has made many discoveries while carrying out their ambitious scientific observations of Itokawa. This release summarizes and reports the major scientific and engineering achievements in advance of Hayabusa’s unprecedented and historic descent to the surfaceof Itokawa for sample collection middle to later this month (November 2005).
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Itokawa-05.jpgOrbiting around Itokawa (2)63 visiteHayabusa is a technology demonstration spacecraft focusing on key technologies that are required for future large-scale sample and return missions, yet is also making new scientific observations and discoveries. The technology demonstration component of the mission consists of 5 goals:
1) ion engine propulsion in interplanetary cruise;
2) ion engine propulsion in combination with an Earth gravity assist;
3) autonomous guidance and navigation using optical measurements;
4) collection of surface samples in an ultra-low gravity environment and
5) the direct recovery of these samples on the ground after its return from interplanetary flight.
To date the Hayabusa project has accomplished these demonstrations up through
the third goal.
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Itokawa-06.jpgOrbiting around Itokawa (3)55 visiteSpecifically, at the time of arrival at Itokawa, Hayabusa had driven its proprietary new ion engines for 26.000 hours, including their operation during an Earth flyby.
It has also perfectly completed a period of hybrid optical navigation followed by
precise guidance and navigation of the spacecraft during its station keeping period around Itokawa.
These engineering achievements are the primary mission of Hayabusa and their successful completion is a great achievement.
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