Voyager 2 may have been the second of NASA’s famous twin exploration spacecraft but it actually launched first, on August 20, 1977. Eight and a half years later it became the first (and, to date, last) spacecraft to visit Uranus, at 31,500 miles across the third largest planet in the Solar System. Voyager 2 made its closest pass by Uranus 32 years ago, giving us our best views ever of the enormous ice giant planet and its moons.
Voyager 2 may have been the second of NASA’s famous twin exploration spacecraft but it launched first, on August 20, 1977. Eight and a half years later it became the first (and last) spacecraft to visit Uranus, at 31,500 miles across the third largest planet in the Solar System. Voyager 2 made its closest pass by Uranus 31 years ago, giving us our best views to this day of the enormous ice giant and its moons.
I was just checking out this HiRISE image from the Mars Reconnaissance Orbiter (MRO) and thought I’d tweak it and share it here…it’s a rare and very nice in-action shot of fine ice and dust particles streaming over the edge of a sheer 2,300-foot-high cliff in the north polar region of Mars. Billowing clouds of dust at the base extend hundreds of feet outwards. The top of the cliff, at upper right, is a plateau covered with carbon dioxide frost – a.k.a. dry ice. The layers of the cliff wall show varying bands of reddish-brown and pale pink coloration (the image itself is false-color) that give clues to their composition, which is mostly different combinations of ice, dust and rock.
I rotated the image from its original release because I felt this way the perspective of stuff falling down over a cliff is better represented. I also level-adjusted and sharpened the image to bring out some detail in the surfaces and dust cloud.
It’s believed that these avalanches are caused by the warming of the carbon dioxide frost during the Martian spring, both on the surface and beneath the ground. Sublimation of frozen CO2 causes it to expand and, in some instances, burst from the ground in dust-filled geysers.
Image: NASA/JPL/University of Arizona. Edited by J. Major.