ENORMOUS, ALMOST-VERTICAL caves have been spotted on Mars by NASA’s Mars Reconnaissance Orbiter spacecraft.
The caves, or pits, measure 180 metres and 310 metres wide, and at first glance seem completely black.
But a closer inspection reveals details within. Scientists have enlarged the images and adjusted the contrast to bring out more details inside the pits.
Both pits shows boulders and sediments against the walls, with lighter-coloured wind-blown sand dunes on the floors.
In each case, the eastern walls of the pits are very steep while the western walls are more sloped, gradually merging into the floors.
Scientists will pour over these images to try to decipher the origin and geological history of the pits.
Images courtesy NASA / JPL / University of Arizona.
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