September 6, 2012
Mars Express Sends Back Images Of Hadley Crater
Lee Rannals for redOrbit.com — Your Universe Online
The image shows the crater, which lies to the west of the Al-Qahira Vallis, in the transition zone between the old southern highlands and the younger northern lowlands.
The Mars Express image shows that the crater was struck multiple times by large asteroids or comets after its initial formation, and subsequent infilling with lava and sediments. Some of the impacts have been partly buried, with subtle hints of a number of crater rims to the west, and wrinkle ridges to the north of the main crater floor.
In one of the images, the crater appears shallower than the opposite side, according to ESA. The space agency said this difference can be explained by an erosion process known as mass wasting, which is when surface material moves down a slope under the force of gravity.
"Mass wasting can be initially started by a range of processes including earthquakes, erosion at the base of the slope, ice splitting the rocks or water being introduced into the slope material," ESA said in a press release. "In this case there is no clear indication which process caused it, or over what timescales this may have occurred."
The agency also pointed out smaller craters within Hadley, which show evidence for volatiles, possibly water ice beneath the surface.
"With the impact that forms the craters, this ice would mix with surrounding materials to form a kind of 'mud', which would then spread over the surface as ejecta," ESA said.
Scientists believe these volatiles were excavated by the impacts, and may indicate the presence of ice to a depth of around hundreds of feet.
In another image showing Hadley Crater, you can see a deep view into the martian crust within the walls of the crater, providing scientists an insight into the history of Mars.