Continuing our impact related theme of the past two days, a new discovery has been made on Mars that incoming meteors large enough to create craters are also causing dust avalanches. The avalanches are caused by the shockwave that precedes the incoming impactor which is traveling at several times the speed of sound. Because the Martian atmosphere is not as dense as Earth's, a lot of meteors that would burn up in our atmosphere survive on Mars to create new craters.
In looking at the HiRise images of the crater cluster there were a large number of dust avalanches observed, over 64,000. The "ah-hah!" moment came when one photo showed a pair of scimitar-shaped features were seen which were subsequently shown to precisely fit computer models of the blast wave.
Read More About It: http://uanews.org/node/43798.
Sky Guy in VA