Mars Reconnaissance Orbiter (MRO)
|
|
|
TRA_000840_2750_IRB-003.jpgChasma Boreale (3)53 visiteImage TRA_000840_2750 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on September 30, 2006.
The image is centered at 84,7° North Latitude and 16,1° East Longitude. The range to the target site was 319 Km (about 199 miles). At this distance the image scale is 32 cm/pixel (with 1 x 1 binning) so objects ~96 cm across are resolved.
The image shown here has been map-projected to 25 cm/pixel and North is up. The image was taken at a local Mars time of 3:28 PM and the scene is illuminated from the West with a solar incidence angle of 68,1°, thus the Sun was about 21,9° above the horizon.
At a Solar Longitude of 114,2°, the season on Mars is Northern Summer / Southern Winter.
|
|
TRA_000840_2750_IRB-004.jpgChasma Boreale (4)54 visitenessun commento
|
|
TRA_000840_2750_IRB-005.jpgChasma Boreale (5)53 visitenessun commento
|
|
TRA_000840_2750_IRB-007.jpgChasma Boreale (6)54 visitenessun commento
|
|
TRA_000840_2750_IRB-008.jpgChasma Boreale (7)55 visitenessun commento
|
|
TRA_000878_1410_RGB.jpgTerra Sirenum53 visiteThis region receives very little sunlight in Southern Winter, and the bluish areas consist of frost. At the latitude of this image, frost is most likely composed of water because the temperature is not low enough for CO2 condensation. The reddish regions are locations where frost has been removed, most likely by sublimation. The dark, unfrosted regions (for example, in the channel of the gully on the far right) represent the most recent activity in the gullies and are possibly a result of seasonal melting.
|
|
Terra_Sirenum-PIA09101-01.jpgSeasonal frost in Terra Sirenum (according to Lunexit)53 visitenessun commentoMareKromium
|
|
Terra_Sirenum-PIA09101.jpgSeasonal frost in Terra Sirenum (according to NASA)57 visiteCaption NASA originale:"This image of the Terra Sirenum Region of Mars was taken by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) at 09:18 UTC (4:18 a.m. EST) on Nov. 25, 2006, near 38,9° South Lat. and 195,9° East Long. CRISM's image was taken in 544 colors covering 0,36-3,92 micrometers and shows features as small as 18 mt (60 feet) across.
At this time, Mars' Southern Hemisphere was experiencing mid-Winter. During Martian Southern Winter, the Southern Polar Cap is covered and surrounded by CO2 frost and water frost. This is unlike Earth, whose frozen Winter precipitation is made up of only one volatile -- water. The CO2 frost evaporates, or sublimates, at a lower temperature than water frost. So, during Spring, the CO2 ice evaporates first and leaves a residue of water frost, which later sublimates as well.
The image shown here covers part of a crater rim, which is illuminated from the upper left. North is at the top.
The topography creates a cold microenvironment on the South side of the rim that is partially protected from solar illumination. That cold surface contains an outlier of the southern seasonal frost about 15° of Lat. closer to the Equator than the average edge of the frost at this season.
The top image was constructed from 3 infrared wavelengths that highlight the bluer color of frost than the background rock and soil. Note that the frost occurs both on sunlit and shaded surfaces on the south side of the rim. The shaded areas are still visible because they are illuminated indirectly by the Martian Sky.
The bottom image was constructed by measuring the depths of spectral absorption bands due to water frost and CO2 frost and displaying the results in image form. Blue shows strength of an absorption due to water frost near 1,50 mmts and green shows strength of an absorption due to CO2 frost near 1,45 mmts. Red shows brightness of the surface at 1,33 micrometers -- outside of the frost absorption bands -- in order to show the relationship of frost to the illuminated crater rim.
In comparing the top and bottom images, note that water frost occurs in many locations on the south-facing side of the crater rim, both in sunlit and shaded areas. Because it faces away from the Sun, this side of the crater rim is colder than the north, Sun-facing side.
This favors the formation of frost. In contrast, CO2 frost occurs only in the coldest, most shaded areas".MareKromium
|
|
Valles_Marineris-MRO-PCF-LXTT.jpgFeatures of Valles Marineris (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 177 visitenessun commentoMareKromium
|
|
Vastitas_Borealis-DD-PIA12876.jpgCaught in the Act (Natural Colors; credits: NASA/JPL-Caltech/University of Arizona - Additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)73 visiteThis image was targeted to study Knobs in Mars' Northern Plains (Vastitas Borealis), just North of Scandia Crater. What surprised scientists was the presence of a Dust Devil passing by.
As on Earth, Dust Devils form when ground heated by sunlight warms the air above it. The hot air rises, forming an updraft accompanied by vortical motions.
Because warm ground is a requirement, Dust Devils on Mars generally form in late Spring to Summer, especially at high Latitudes.
This image was taken in early Spring (2010), at a latitude of about 61° North. No Dust Devil has been seen this far from the Equator at such an early season before.MareKromium
|
|
Vastitas_Borealis-TRA_000828_2495_IRB-1-PCF-LXTT.jpgBuried Crater and Polygons in Vastitas Borealis (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)361 visitenessun commentoMareKromium
|
|
Vastitas_Borealis-TRA_000828_2495_IRB-2-PCF-LXTT.jpgBuried Crater and Polygons in Vastitas Borealis (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)415 visitenessun commentoMareKromium
|
|
| 2237 immagini su 187 pagina(e) |
 |
|
|
|
|
|
|
|
|
186 |
|
