The giant, astronaut-sucking vortex of dust that raises havoc in the movie Mission to Mars is pure fiction, but there are nevertheless real vortexes in the planet's thin atmosphere. They are similar to dust devils in desert areas on Earth, miniature tornadoes caused by heating of air close to the ground. Dust devils on Mars were first seen in images taken by the Viking orbiters. In 1997 the Mars Pathfinder lander sensed one passing right over it. Now the eagle-eye resolution of the Mars Global Surveyor has captured many of them in the act. Images presented by K. S. Edgett and Michael Malin (Malin Space Science Systems) at this week's Lunar and Planetary Science Conference in Houston, Texas, show shadow-casting dust devils. Other regions of the surface display vast numbers of criss-crossing, sometimes meandering, dark streaks. The researchers suspected dust devils as the culprits, but it wasn't until examining an image taken in December 1999 that they could prove it. At the end of one curly dark streak is the smoking gun: the swirling cloud of bright dust that is the devil himself.
Mars Global Surveyor caught this 100-meter-wide dust devil dancing across Promethei Terra in the planet's southern hemisphere. Researchers had been puzzling over what was forming the countless dark streaks on the planet, until they found one of the culprits in the act.
(Quelle: sky and telescope)