The dust devil at the top of the picture has a diameter of four meters. It formed 400 meters from the Phoenix spacecraft. Image: NASA / JPL-Caltech / University of Arizona / Texas A & M University
Reading The nights are getting colder? also on Mars. That was the landing lander Phoenix felt in the past week. For the first time, so-called "dust devils" could be seen in the vicinity of the landing site above the Arctic Marvel: whirlwinds with a diameter of two to five meters. The cause of the mini tornadoes were the increasing temperature differences between day and night, reported the space agency Nasa. The ground crew discovered on recordings of 9 September at least six different whirlwinds. "We were surprised when we saw a dust devil very clearly in a photo, even though we only did the normal image editing, " said Mark Lemmon of Texas A & M University, who oversees the Phoenix stereo camera. "After further processing, dust devils appeared on twelve pictures."

On the same day, the lander's pressure sensor registered a sudden sharp drop in pressure. "We've seen vortex-shaped structures throughout the entire mission, lowering air pressure for 20 to 30 seconds, especially around lunchtime, " said team member Peter Taylor of York University, in Toronto, Canada. "In the last few weeks these whirls have become stronger and now they seem to have enough power to whirl up dust from the ground."

The temperatures in the area around the lander fluctuate by 60 degrees during the day: During the day, it gets around minus 30 degrees Celsius, at night, temperatures drop to minus 90 degrees Celsius. The dust devils are created when the sun warms the ground during the day. This also makes the air above it warmer and rises in a spiraling upward motion. On 9th September, strong winds swept the desert-like Martian landscape at speeds of up to five meters per second. Measurements from the orbit had already suggested that there would have to be dust dust at the landing site of Phoenix, but so far nothing was known about their size and frequency. "I'm curious if this was an isolated event or if we'll see more dust devils in the coming weeks, " said Mark Lemmon.

The researcher does not see any danger to the probe: because the air on Mars is very thin, it can not stir up much dust. The solar sails, the robot arm and the shell of the probe are built so robust that they can easily handle the load. The Mars robot Spirit, which has been exploring the planet for four years near the equator, has already photographed much larger dust devils. display

Message from NASA Ute Kehse

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