APOD 3.9

This weeks picture is of defrosting sand dunes. By observing the changing patterns in sand dunes, scientists can learn about the interaction between the Martian surface and the atmosphere. Dune activity can help them understand the rate at which the Martian wind moves sediments around, as well as to estimate how long it takes for windblown sand to abrade the surfaces of rocks; not to mention our Mars landers. Dunes were first detected by the Mariner 9 spacecraft in the early 1970s, and are actively studied by the Mars Global Surveyor orbiter today.These ripples, like small sand dunes, are common on Mars and are usually found in low-lying areas and inside craters. They can be up to 20 feet tall and form really crazy and dramatic patterns. SWEET!