| Piú votate - A Tribute To Mars Global Surveyor |
Phobos-Phobos_Monolith-01.jpgThe "Phobos' Monolith" (EDM n.1)381 visiteComunque - e per concludere questo primo approccio con Phobos - l'idea di tentare un atterraggio su questo (e chissà poi perchè...) misterioso e, a quanto vediamo, enigmatico corpo celeste, non è venuta soltanto alla NASA.
Conoscete la storia della Sonda Russa "Phobos 2", del suo avvicinamento a Phobos e del relativo "incidente" che ne seguì?
No?!?
Ve ne parleremo più avanti, sempre, in questa Sezione...
(22 voti)
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Phobos-Phobos_Monolith-06.jpgThe "Phobos' Monolith", like you've never seen it before! (an Image- composite by Dr Marco Faccin)1600 visiteDal nostro grandissimo Marco Faccin, una spettacolare ricostruzione in Alta definizione del famoso "Monolito di Phobos" il quale, finalmente, sembra risolversi davanti ai nostri occhi per ciò che esso realmente è: un macigno (boulder) a pianta triangolare, curiosamente caratterizzato da un'albedo di gran lunga superiore a quella dell'intero paesaggio al quale accede.
Il giorno in cui "2001 - A Space Odyssey" diventerà realtà, purtroppo, deve ancora attendere la sua alba...MareKromium
(18 voti)
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Volcanoes-Arsia_Mons-E05-1721_1722_arsia100.jpgArsia Mons Volcano and "spiral clouds" (Natural Colors; credits: NASA/JPL/MSSS)90 visiteCaption NASA originale:"One of the benefits of the MGS-MOC Extended Mission is the opportunity to observe how the planet's weather changes during a second full martian year. This picture of Arsia Mons was taken on June 19, 2001; Southern Spring equinox occurred the same day. Arsia Mons is a volcano nearly large enough to cover the state of New Mexico. On this particular day (the first day of Spring), the MOC wide angle cameras documented an unusual spiral-shaped cloud within the 110 Km diameter caldera - such as the summit crater - of the giant volcano. Because the cloud is bright both in the red and blue images acquired by the wide angle cameras, it probably consisted mostly of fine dust grains. The cloud's spin may have been induced by winds off the inner slopes of the volcano's caldera walls resulting from the temperature differences between the walls and the caldera floor, or by a vortex as winds blew up and over the caldera. Similar spiral clouds were seen inside the caldera for several days; we don't know if this was a single cloud that persisted throughout that time or one that regenerated each afternoon".
(17 voti)
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Craters-Newton_Crater-01-42S_158W_30.jpgGullies inside Newton Crater - Terra Sirenum (Natural Colors; credits: NASA/MGS/MSSS)104 visiteCaption NASA originale:"This picture shows gullies in a crater at 39.0°S, 166.1°W and it is one of the highest-resolution images ever obtained from Mars. Also in this case the resolution is 1,5 meters (5 feet) per pixel".
(17 voti)
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North_Polar_Features-Cl-louds-Mars_Weather-PIA05079.jpgWeather Patterns over the North Pole of Mars (Natural Colors; credits: NASA/MGS/MSSS)94 visiteMars Global Surveyor entered Mars orbit on 12 September 1997. The 8 Earth Years that MGS has been in orbit span portions of 5 Martian Years. One of the critical science activities that the MOC has been engaged in for the past 8 years has been to document daily changes in the Martian Weather. Each day that MOC is operating, the red and blue wide angle cameras are used to build up a daily global map. These maps provide a record of the Planet's changing meteorological conditions. One important discovery that has been made is that the Red Planet has "repeatable weather patterns". In light of weather-related problems and disruptions that occur every year on Earth, one can only imagine how nice it would be if our planet followed a similar, repeated pattern. The 4 pictures shown here provide an example of one of the weather phenomena that repeat each MY. Each picture shows the North Polar Region of Mars during the Northern Summer Season. Each picture is a composite of several images acquired at different visible wavelengths to give a color view of the planet. Each picture was taken about 1 Mars year apart, and each shows an annular (circular) cloud located over the same terrain each summer.
The first picture, acquired in April 1999, is actually not from the MGS MOC instrument. It was obtained by the Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) and was originally released by the Space Telescope Science Institute on 19 May 1999. The reason there is no MOC image for April 1999 is a product of the MGS spacecraft's 8-year history at Mars. MGS was certainly in orbit at the time, and it was taking data during the month of April. However, the camera did not obtain any images between 17 and 28 April because the spacecraft encountered, and then had to be recovered from, a problem. It was at this time that the spacecraft team realized that there is something obstructing the full movement of MGS's high gain antenna. A work-around was created and the mission has continued, ever since, but the down-side was that MOC did not have the opportunity in 1999 to provide detailed observations of the north polar, summertime, annular cloud.
The remaining three pictures show MGS MOC views of the cloud feature, as it appeared in the subsequent 3 Mars years. Each year, the cloud appeared at about the same time or slightly earlier than in the previous year. Despite its superficial resemblance to a hurricane or cyclone on Earth, the northern summer annular cloud does not rotate. The cloud forms as different currents of air merge in the morning hours in the polar region; by afternoon, the annular cloud typically dissipates or breaks up into smaller clouds.
MGS MOC has observed other repeated phenomena over the course of its 8-year mission orbiting Mars. These include dust storms that repeat, year after year, in the same location within a week or two of the time it occurred in the previous year. They also include dust devils in northern Amazonis, which start up shortly after the first day of spring, and keep occurring nearly every afternoon until a few days into the autumn season. MOC is continuing its mission to monitor the planet -- in 2006, MOC's weather observations will be used to provide guidance for the aerobraking maneuvers of the Mars Reconnaissance Orbiter (MRO). MOC images will show whether dust storms are occurring, and whether the dust suspended by these storms will impact the density of the atmosphere at the altitudes that MRO is passing through to slow the spacecraft and change its orbit to the one desired for the MRO primary mission.
(16 voti)
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Volcanic_Features-Plume-Tharsis-PIA04285.jpgAn isolated "Water Ice Cloud" over Tharsis or a volcanic "Plume"? (Saturated Natural Colors; credits: NASA/JPL/MSSS)133 visiteOriginal caption:"This composite of red and blue MGS-MOC daily global images acquired on 6 July 2005 shows an isolated water ice cloud extending more than 30 Km (more than 18 miles) above the Martian surface. Clouds such as this are common in late Spring over the terrain located South-West of the Arsia Mons volcano. Arsia Mons is the dark, oval feature near the limb, just to the left of the "T" (in the "Tharsis Montes" label).
The dark, nearly circular feature above the "S" (in "Tharsis") is the Pavonis Mons Volcano and the other dark circular feature, above and to the right of "S" in "Montes," is Ascraeus Mons.
Illumination is from the left/lower left.
Season: Northern Autumn/Southern Spring".
Nota: purtroppo non ci sono vulcanologi nel Gruppo Lunar Explorer, ma la sensazione (nulla di più) che la "isolata nuvola di ghiaccio d'acqua", come la chiama la NASA sia, in realtà, il residuo di un evento vulcanico, è molto intensa (confrontate la sua forma con qualcuna delle "volcanic plumes" di Io...).
(16 voti)
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Aeolian_Features-DD_and_Dust_Storms-2003_06_02-00.jpgDust Storms and Dust Devils between Syria Planum and Claritas Fossae (Enhanced Natural Colors; credits: NASA/MGS/MSSS)91 visiteCaption NASA originale:"This color-enhanced composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle images shows dust-raising events (small dust "storms" and a few very large dust devils) in the Syria/Claritas Region around 2 p.m. MLT on May 21, 2003. The Region is southwest of the Labyrinthus Noctis, near 14°S, 108°W. Sunlight illuminates the scene from the left; winds were blowing from the west/southwest when the picture was taken. This composite was constructed from a full-resolution (240 meters per pixel) red wide angle image and a much lower resolution (7,5 Km per pixel) blue wide angle image acquired at the same time".
(16 voti)
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Craters-Newton_Crater-00-39S_166W_30.jpgGullies inside Newton Crater - Terra Sirenum (Natural Colors; credits: NASA/MGS/MSSS)94 visiteCaption NASA originale:"Both pictures show gullies (gully--->plur.: gullies: "gole" o "crepacci scoscesi") on the walls of two different meteor impact craters that occur in Newton Basin in Sirenum Terra, Mars. This picture, showing gullies in a crater at 42.4°S, 158.2°W, exhibits patches (patch-->geol.: "placche" o "macchie") of wintertime frost on the crater wall and dark-toned sand dunes on the floor. Its resolution is 1,5 meters (5 feet) per pixel - objects the size of school buses can be resolved in the full size image. The gullies in these craters originate at a specific layer and may have formed by release of groundwater to the martian surface in geologically recent times".
(16 voti)
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Craters-Gusev_Crater-R1300473_474.jpgGusev Crater Landscape from MGS (Extremely Enhanced Natural Colors; credits:NASA/JPL-MSSS)123 visiteSi tratta di un'immagine a colori ad HD semplicemente fantastica, ottenuta dalla Sonda Mars Global Surveyor e relativa (in parte) all'area di lavoro di Spirit. Abbiamo scelto di mostrarVi questo frame per almeno 3 buoni motivi: 1) perchè si tratta di un frame bellissimo; 2) perchè ci fa vedere bene i "colori di Marte" (che, dall'alto, sembrano diversi da quanto ci mostrano le Sonde che stazionano sulla superficie e 3) perchè ci aiuta a cogliere, usando i nostri occhi, la sensazione che proveremmo se ci trovassimo fisicamente su una nave spaziale, in orbita intorno a Marte.
(16 voti)
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Volcanoes-Pavonis_Mons.jpgPavonis Mons (Darkened Natural Colors; credits: NASA/MGS/MSSS)79 visiteCaption NASA originale:"This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle color composite image, obtained in December 2003, shows the middle of the three Tharsis Montes, Pavonis Mons. This is a broad shield volcano -similar to the volcanoes of Hawaii - located on the Martian equator at 113°W. The volcano summit is near 14 Km (~8.7 mi) above the martian datum (0 elevation); the central caldera (crater near center of image) is about 45 Km (~28 mi.) across and about 4.5 Km (~2.8 mi.) deep. Sunlight illuminates the scene from the lower left".
(15 voti)
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Dunes-S2200554sub-00.jpgMigrating Dunes (Original NASA/MGS/MSSS b/w Frame)108 visiteCaption NASA originale:"This MGS-MOC image shows a suite of dunes in one of the several North Polar Dune Fields. The bright surfaces adjacent to some of the dunes are patches of frost. These dunes spend much of the Autumn, Winter, and Spring seasons covered with CO2 frost. Only in late Spring and in Summer are the dark windblown sands fully exposed.
Over the course of the 9+ years of the MGS mission, the MOC team has sought evidence that sand dunes may be migrating downwind over time. However, no clear examples of the movement of a whole dune have been identified. On Earth, such movement is typically detectable in air photos of the smallest active dunes over periods of a few years. Owing to the fact that the North Polar Dunes spend much of each Martian Year under a cover of frost, perhaps these move much more slowly than their frost-free, terrestrial counterparts. The sand may also be somewhat cemented by ice or minerals, likewise preventing vigorous dune migration in the present environment.
This view covers an area approximately 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left. The dunes are located near 79.8°N, 127.1°W, and the picture was acquired on 11 September 2006.
(14 voti)
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Craters-Unnamed_Crater_with_Dark_Streaks-2003_08.jpgDark Slope Streaks on the edge of an Unnamed Crater (Saturated Natural Colors; credits: NASA/MGS/MSSS)97 visiteCaption NASA originale:"This June 2003 MGS-MOC image shows a crater rim mantled with fine dust near 7.6°N, 171.8°W. Occasional avalanches of dust have created dark streaks that are tapered at their source and broaden downslope.
A suite of particularly large streaks are seen in the lower right quarter of the picture. The MOC narrow angle camera does not take color images; this full-resolution (1,5 m/pixel; 5 ft/pixel) picture has been "colorized" using data from a previous color image of Mars.
Sunlight illuminates this scene from the lower left".
(14 voti)
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