an international team of astronomers first recorded the movement of the giant sand dunes on Mars, which until now was considered forever frozen laboratornyi structures. About the opening told the journal Science.
the Giant sand dunes on the red planet regularly photographed since the beginning of 2000-ies. Pictures are made as the Mars Rovers and the orbiters.
the images these structures are always scientists seemed unchanged. Therefore, it was assumed that the dunes were formed in the deep past, when Mars was a stable atmosphere. It was assumed that the powerful wind moved the dunes, but at some point, they froze.
a New study has disproved this hypothesis. Scientists re-analyzed the images of Magadan, and literally laid them on the pixels. They found that giant sand dunes in contrast to the smaller sand dunes are composed of grains of two sizes. Some of them are heavier, so they move in any case would be difficult.
However, a comparison of images showed that giant sand dunes moving. The researchers focused on the study of two sites near the equator of Mars: the McLaughlin crater and on the plains Neely-Fosses.
They were looking for signs of movement, comparing time-lapse image of each plot at intervals of 7.6 and 9.4 years, respectively. It turned out that megadune in both regions, moving about 10 inches per year. At about the same speed moving megadune in the LUT desert in Iran.
“It’s amazing that megadyuny move on Mars, says Jim Zimbelman, a planetary geologist from the Museum of air and space Smithsonian. – Just a few decades ago, there was no evidence that the Sands on Mars was once a mobile. None of us thought that the winds there were quite strong”.
In this case, the team members assumed that the winds on Mars can accelerate fine grains of sand. These grains begin to roll and bounce, picking up speed. When faced with larger grains, they act as a battering RAM, causing them to move. A similar process of creep-induced impacts observed on the Ground.
Previously established atmospheric models of Mars suggest that the red planet is rarely any wind capable of moving sand. Perhaps a new discovery will make to revise these models.
“Amazing that the team was able to detect these changes on Mars, says Ralph Lorenz, a scientist, a planetary scientist from the applied physics Laboratory of Johns Hopkins University. – Now we can measure the surface processes of another planet, which occur only a few times faster than growing our hair.”
