| Piú viste - A Tribute To Mars Global Surveyor |
Thaumasia_Region-The_Electric_Dunes-01.jpgThaumasia Dunes: the brightest dunes of Mars (EDM n.1)99 visitenessun commento
|
|
Marte_Vallis-MGS-PCF-LXTT.jpgThe alleged "Frozen Ocean" of Marte Vallis (Natural Colors; credits for the additonal process. and color.: Dr Paolo C. Fienga - Lunexit Team)99 visitenessun commentoMareKromium
|
|
South_Polar_Regions-SPRC.jpgSublimation at the South Polar Residual Cap (Absolute Natural Colors; credits: Dr Paolo C. Fienga - Lunexit Team)99 visiteCaption NASA:"This MGS-MOC image shows a portion of the South Polar Residual Cap where the effects of Sublimation are apparent.
Over extended periods of time, Sublimation "eats" away at the smoother appearing material (largely composed of frozen CO2), darkening the Scarps and creating the irregularly shaped depressions that are present throughout much of the scene".
Location near: 87,1° South Lat. and 69,3° West Long.
Image width: ~3 Km (~1,9 miles)
Illumination from: upper left
Season: Southern SummerMareKromium
|
|
Craters-Newton_Crater-00-39S_166W_30.jpgGullies inside Newton Crater - Terra Sirenum (Natural Colors; credits: NASA/MGS/MSSS)98 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".
|
|
Volcanoes-Arsia_Mons-03-PIA04294.jpgArsia Mons and its "clouds" (3) - 25 February 2005 (Extremely Saturated Natural Colors; credits NASA/JPL/MSSS)98 visiteOriginal caption:"The spiral dust cloud over Arsia Mons repeats each year, but observations and computer calculations indicate it can only form during a short period of time each year. Similar spiral clouds have not been seen over the other large Tharsis volcanoes, but other types of clouds have been seen. The spiral dust cloud over Arsia Mons can tower 15 to 30 Km (9 to 19 miles) above the volcano. The white and bluish areas in the images are thin clouds of water ice. In the 2005 case, more water ice was present than in the previous years at the time the pictures were obtained. For scale, the caldera of Arsia Mons is about 110 Km (about 68 miles) across, and the summit of the volcano stands about 10 Km (6 miles) above its surrounding plains"
|
|
South_Polar_Features-Summer-01.jpgSouth Polar Summer (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)97 visitenessun commentoMareKromium
|
|
North_Polar_Features-Chasma_Boreale-PIA07195-00-PCF-LXTT.jpgFeatures of Chasma Boreale (Original NASA/MGS/MSSS b/w Frame) 96 visiteCaption NASA originale:"This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark Sand Dunes in the North Polar Region of Mars. They are streaming away (toward the left) from a low escarpment at the edge of an outlier of Polar Water Ice (the bright area on the right). The picture covers an area about 3 Km (1.9 mi) wide and is located near 80,7° North Lat. and 80,2° West Long.. Sunlight illuminates the scene from the lower left".
|
|
North_Polar_Regions-Chasma_Boreale-MGS-00.jpgBrown Dunes in Chasma Boreale (Original NASA-MSSS-MGS b/w frame)96 visiteCaption NASA originale:"This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers and dunes in Chasma Boreale, a large depression in the North Polar Region".
Location near: 85,2°N; 10,4°W
Image width: ~3 Km (~1.9 mi)
Illumination from: lower left
Season: Northern Summer
|
|
North_Polar_Features-Cl-louds-Mars_Weather-PIA05079.jpgWeather Patterns over the North Pole of Mars (Natural Colors; credits: NASA/MGS/MSSS)96 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.
|
|
North_Polar_Regions-Dunes.jpgNorth Polar Dunes (Original NASA/MGS/MSSS b/w Frame)96 visiteCaption originale:"This MGS-MOC image shows two "Barchan Dunes" in the North Polar Region of Mars. The orientation of the Dunes, with the steep faces pointed toward the South-East, indicates that the winds responsible for their formation blew from the North-West. At the time this image was acquired by MOC, the dunes and surrounding plains were covered by seasonal carbon dioxide frost".
Location near: 73,8° North Lat. an 40,8° West Long.
Image width: ~3 Km (~1,9 mi)
Illumination from: lower left
Season: Northern Winter
|
|
Earth_and_Moon_from_Mars-00.jpgEarth and Moon from Mars95 visiteCaption originale:"This is the first image of Earth ever taken from another planet that actually shows our home as a planetary disk. Because Earth and the Moon are closer to the Sun than Mars, they exhibit phases, just as the Moon, Venus, and Mercury do when viewed from Earth. As seen from Mars by MGS on 8 May 2003, Earth and the Moon appeared in the evening sky. The MOC Earth/Moon image has been specially processed to allow both Earth (with an apparent magnitude of -2.5) and the much darker Moon (with an apparent magnitude of +0.9) to be visible together. The bright area at the top of the image of Earth is cloud cover over central and eastern North America. Below that, a darker area includes Central America and the Gulf of Mexico. The bright feature near the center-right of the crescent Earth consists of clouds over northern South America. The image also shows the Earth-facing hemisphere of the Moon, since the Moon was on the far side of Earth as viewed from Mars.The slightly lighter tone of the lower portion of the image of the Moon results from the large and conspicuous ray system associated with the crater Tycho.
|
|
Earth_and_Moon_from_Mars-01.jpg"Us", from Mars (EDM)95 visitevedi il commento al frame precedente
|
|
| 512 immagini su 43 pagina(e) |
 |
|
|
|
|
16 | |
|
|
|
|
