A towering dust devil casts a serpentine shadow over the Martian surface in this stunning, late springtime image of Amazonis Planitia.
The length of the shadow indicates that the dust plume reaches more than 800 meters, or half a mile, in height. The tail of the plume does not trace the path of the dust devil, which had been following a steady course towards the southeast and left a bright track behind it.
The delicate arc in the plume was produced by a westerly breeze at about a 250-meter height that blew the top of the plume towards the east. The westerly winds and the draw of warmth to the south combine to guide dust devils along southeast trending paths, as indicated by the tracks of many previous dust-devils. The dust plume itself is about 30 meters in diameter.
Numerous bright tracks trend from northwest to southeast. It is interesting to see that these tracks are bright, whereas dust-devil tracks elsewhere on Mars are usually dark. Dark tracks are believed to form where bright dust is lifted from the surface by dust devils, revealing a darker substrate.
more
http://www.uahirise.org/ESP_026051_2160
No comments:
Post a Comment