Pictures From Mars-Credit

Credit Pictures From The Red Planet Mars Along with Information Latest release Credit: NASA/JPL/University of Arizona ------------------ ------------------------------------------------------------------------------ Kaiser Crater Dune Field (ESP_020942_1330) : NASA/JPL/University of Arizona -- --------------------------------                        -------------------------------------------------------------- Go with the Flow (ESP_020822_2220) Credit: NASA/JPL/University of Arizona This image shows flows with rather large ridges extending down off of the central mountains of Moreux Crater. What made those flows? It doesn't look like lava, and the central mountains are not volcanoes--they were thrust up by the impact event. Instead, it may be that these were flows of ice, or glaciers. There are lots of boulders on the surface, and glaciers tend to carry lots of rocks. The Shallow Radar (SHARAD) experiment on MRO is able to penetrate through ice, confirming that many features such as this one are composed of ice, with a thin cover on non-icy material. The existence of glaciers on Mars was controversial more than 10 years ago, but not today. So far we have seen no evidence for currently active glaciers on Mars, but maybe they are moving very slowly. This image is actually a repeat image of this site. Written by: Alfred McEwen Original release: 3 February 2011 ---------------------------------------------------------------------------------------------- - - Spider Terrain (ESP_020955_0930) Credit: NASA/JPL/University of Arizona The actual term used to describe this type of terrain is "araneiform," although "spider" is apt because of what the formation looks like to us. Sublimation (when a solid goes directly to a gas) is a cause of these striking patterns. ------------------------------------------------------------------------------------------------ Conjoined Twins (ESP_020894_1395) Credit: NASA/JPL/University of Arizona This image shows a remarkable double crater with a shared rim and North-South trending ejecta deposits. These two craters must have formed simultaneously. The bolide may have consisted of two objects of the same mass that were loosely connected, perhaps similar to comet 103P/Hartley 2, which the Deep Impact spacecraft (EPOXI mission) encountered on 4 November 2010 (seehere). Many more asteroids than comets impact Mars, but asteroids also come in double shapes, like asteroid Itokawa explored by the Japanese Huyabusa mission. The bolide must have separated into two distinct pieces prior to impact in order for two craters to be recognizable. Written by: Alfred McEwen Original release: 9 February 2011 ------------------------------------------------------------------------------------------------ True Gullies on Mars (ESP_020940_1315) Credit: NASA/JPL/University of Arizona This images shows many channels from 1 to 10 meters (approximately 3 to 33 feet) wide on a scarp in Hellas impact basin. On Earth we would call these "gullies." Meanwhile, the much larger landforms that are typically called "gullies" on Mars would be called "ravines" on Earth. Written by: Alfred McEwen Original release: 16 February 2011 _____________________________________________________________________--- -                                How Old are Rocks on Mars? (ESP_020945_1690) Credit: NASA/JPL/University of Arizona Some of the largest landslides known in the Solar System have happened on Mars. These are interesting phenomena, but they also sometimes produce excellent exposures of the bedrock geology, in cross-sectional views. The purpose of this image was to view bedrock exposures at a deep level in Valles Marineris. We have only a vague idea how old these rocks are. Crater counts date landscapes, and clearly this is a young landscape with very few impact craters due to the continual mass wasting (landslides) of the steep slopes. The rocks are much older--probably older than the plateaus surrounding Valles Marineris (2 to 3 billion years based on the large craters), unless these are intrusive rocks emplaced later from migrating magma. We need radiometric age dating, either on Mars or from returned samples, to measure the age of igneous (volcanic or plutonic) rock layers within the strata. The age of sedimentary layers such as river or lake deposits can be bracketed by the ages of overlying and underlying igneous layers. Not knowing the absolute ages of bedrock units on Mars is a huge limitation to our understanding of the geologic history. Written by: Alfred McEwen Original release: 16 February 2011 Changes on Dunes in Russell Crater (ESP_021496_1255) Credit: NASA/JPL/University of Arizona HiRISE images of the large sand dunes in Russell Crater have been repeatedly acquired to look for evidence of surface changes. This full image shows diffuse, dark patterns that are likely caused by many dust devils removing bright dust from the surface of the dunes. In addition, as shown in the cutout, narrow troughs continue to form on the steep faces of the sand dunes. These troughs appear to be formed when chunks of carbon dioxide ("dry") ice slides down the face of the dune. The image on the left was taken a bit over a Mars year before the image on the right; both were taken in the springtime. The ice blocks may sometimes slide down the same troughs, but comparison of these two images shows that new troughs have been formed during the past year. The pits near the ends of the troughs may be locations where blocks of ice came to rest and then evaporated away. Written by: Ken Herkenhoff Original release: 9 March 2011 Opportunity Still Knocks (ESP_021536_1780) Credit: NASA/JPL/University of Arizona HiRISE acquired this color image of Santa Maria Crater, with the Opportunity rover perched on the southeast rim. Rover tracks are clearly visible to the east. Opportunity has been studying this relatively fresh 90 meter diameter crater to better understand how crater excavation occurred during the impact and how it has been modified by weathering and erosion since. Note the surrounding bright blocks and rays of ejecta. Spectral information from CRISM indicates a hydrated sulfate at this location. Opportunity is about 6 kilometers from the rim of Endeavour Crater, which CRISM indicates both hydrated sulfates as well as phyllosilicates that formed in a wetter past. Written by: Matthew Golombek Original release: 9 March 2011 Monitoring Sand Motion in Gusev Crater near the Columbia Hills (ESP_021569_1650) Credit: NASA/JPL/University of Arizona  Color Coverage of Candidate Landing Site in Holden Crater (ESP_020812_1530) Credit: NASA/JPL/University of Arizona The four candidate Mars Science Laboratory (Curiosity) landing sites have been completely covered by HiRISE, in stereo. However, the color coverage is only the center 20 percent of each full HiRISE observation.This observation was acquired in color only, to extend the color coverage. The subimage shows an enhanced-color portion where some of the light-toned layered deposits are well-exposed beneath the dark windblown materials. The layers may have been deposited in ancient lakes. Catastrophic floods through this crater may have ripped apart and rearranged large blocks of the layered material. Written by: Alfred McEwen My best wishes Hussain Almousawi The End The End