Credit: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

This view of Mars, the sharpest photo ever taken from Earth, reveals small craters and other surface markings only about a dozen miles (a few tens of kilometers) across. (The spatial scale is 5 miles, or 8 kilometers per pixel). The Advanced Camera for Surveys (ACS) aboard NASA's Hubble Space Telescope snapped this image on Aug. 24, just a few days before the red planet's historic "close encounter" with Earth. Among the Martian surface features are: numerous craters; several large volcanoes of the great Tharsis plateau along the upper left limb; and a large multi-ring impact basin, called Argyre, near image center. These kinds of features from past and present NASA spacecraft that have orbited Mars are also being studied in detail. But they have never before been seen from Earth with this kind of clarity. Subtle outliers of bright, whitish carbon dioxide ice (dry ice) can be seen in the neighborhood of the subliming white south polar cap at lower left, near the bottom of the image. The bright reddish meandering lines seen within the dark regions near the center of the image are caused by sunlight reflecting off the sloping walls of a giant canyon system called Valles Marineris, which cuts across more than 2,000 miles of the planet's surface. The ACS's color capabilities can also be used to reveal other interesting details. For example, there is a reddish tinge to part of the south polar cap, suggesting that there are either dust clouds over the cap or that the ices are mixed with dusty surface materials. Dust clouds over the cap would not be surprising, as the dry ice is actively subliming near the time of the southern summer solstice, causing high winds and dynamic weather patterns. This color image also reveals interesting weather phenomena at the highest northern latitudes. Hubble resolves a variety of clouds over the dark region in the upper right. This region is called Acidalia Planitia, and it is known to be the location of frequent cl

Provider: Space Telescope Science Institute

Image Source: https://hubblesite.org/contents/news-releases/2003/news-2003-22

Curator: STScI, Baltimore, MD, USA

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