Mars is often referred to as a desert world, being bone-dry for the most part, with dust and sand blanketing most of the surface. Some regions are covered in vast sand dunes, reminiscent of deserts like the Sahara on Earth, only much colder. Gale crater, where the Curiosity rover landed in 2012, features extensive dune fields around the base of Mount Sharp, and the rover is now approaching some of them for the first time; their dark color makes them stand out starkly against the surrounding terrain. These dunes are also still active, meaning they are still mobile and shaped by the wind, not just old “fossil” (petrified) dunes which are no longer active.
Last week there was the exciting news that Mars still has flows of briny water occurring now, and this week there is more water-related news: additional findings from the Curiosity rover that the huge Gale crater was once a lake or series of lakes a long time ago. Curiosity had already found evidence that there used to be shallow lakes and streams in this area, but the new data confirms this and suggests that the lake(s) once filled Gale crater and were long-lasting, explaining the formation of Mount Sharp in the middle of the crater and also providing a potentially habitable environment for life.
Another beautiful panoramic image of the foothills of Mount Sharp, taken by Curiosity on Sep. 9, 2015. The mesas, buttes and valleys can be seen in greater detail as the rover keeps getting closer. The image has been white-balanced to show the terrain under more Earth-like lighting conditions. The full-size version of the image is available here.
Wind-eroded rocks on Mars can take many different forms, sometimes resembling common earthly objects. Some good new examples include these long, thin slivers of rock which look like “spoons” and “needles,” seen by the Curiosity rover recently on sols 1089 and 1087. These fragile formations are easier to form in Mars’ weaker gravity and thinner atmosphere and can last much longer than they would on Earth – a unique form of Martian “artwork.”
After extensive investigations of rock layers in Marias Pass, a shallow valley near the base of Mount Sharp, the Curiosity rover is now heading southwest again, to continue gradually climbing the lower slopes of the mountain. Marias Pass is a region with rocks and ground which contain high levels of silica and hydrogen, more evidence that there used to be a lot more water here than there is now.
There are a couple new views of the foothills on Mount Sharp from the Curiosity rover, and they are beautiful. Many layers, mesas and buttes are visible, reminiscent of the American southwest. Curiosity will keep getting closer in the weeks and months ahead. Image processing by Lars (@LarsTheWanderer).
NASA’s Curiosity rover has just reached its third anniversary milestone on Mars, after landing in Gale crater on Aug. 5, 2012, and since then has made some incredible science discoveries, with more to come in the months and years ahead. NASA is celebrating this achievement and you can take part, too!
Some great new images of very finely layered rocks near Jocko Butte on sol 976, from Curiosity. The layers tell a geological story of alternating wet conditions in this area on Mars a long time ago. These thin, delicate layers are an amazing sight! All of the raw images from Curiosity can be seen here.