Released in December, the image is among a series of new views snapped by MRO's HiRISE camera that show intriguing geological features on Mars. Each image covers a strip of Martian ground 3.7 miles (6 kilometers) wide and can reveal a detail about as small as a desk—and so far no sign of Star Wars monsters.
A sharp close-up of the the larger Martian pit revealed sediment and boulders (seen in a picture taken in fall 2010 by the Mars Reconnaissance Orbiter's HiRISE camera), as well as hints of sand that was blown inside and trapped in the deepest and darkest parts of the hole, according to NASA.
Car-size boulders punctuate the bottom of the smaller Martian pit (pictured in a fall 2010 HiRISE image). A bright sand dune laced with windblown ripples covers the sloping western side of the hole.
The two pits are believed to be relatively young, according to NASA. As the pits age, the slopes become shallow and widen as they material at the edges collapses inward.
Among other recently released pictures from NASA's Mars Reconnaisance Orbiter are these images of apparent mud volcanoes on in Acidalia Planitia, a large basin in Mars's northern lowlands (seen in a fall 2010 HiRISE picture).
Mud volcanoes—which also exist on Earth—form when wet, pressurized sediment buried at depth erupts onto the surface. (Related photo: "'Medusa' Worms Found in Mud Volcano.")
A gigantic trough (center) slices through Mars's Tharsis volcanic region in a fall 2010 picture by HiRISE.
Called a graben, the 1.2-mile-wide (2-kilometer-wide) depression formed when a block of the planet's crust dropped down between two faults. In this case, the tectonic movement left nearly vertical walls—each about a kilometer (0.6 mile) deep—on either side.
"From the scarcity of craters inside the graben, it's estimated to be less than a billion years old," principal investigator McEwen said. "This one is nicely defined because it cuts a well-preserved lava flow."
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