NASA's Mars spacecraft captures 'unusual' sand dunes that are 'almost perfectly circular'

The High-Resolution Imaging Experiment (HiRise) colour camera onboard NASA's Mars Reconnaissance Orbiter (MRO) spacecraft has taken a captivating picture of sand dunes that possess circular shapes which are being considered "unusual". “Sand dunes of many shapes and sizes are common on Mars. In this example, the dunes are almost perfectly circular, which is unusual,” said NASA while releasing the photograph.

“They are still slightly asymmetrical, with steep slip faces on the south ends. This indicates that sand generally moves to the south, but the winds may be variable,” added NASA. 

MRO's HiRise camera also snapped some more typical crescent-shaped dunes, reported CNET. "Sand dunes of many shapes and sizes are common on Mars. In this example, the dunes are almost perfectly circular, which is unusual," wrote planetary geologist Alfred McEwen for a HiRise picture-of-the-day feature Thursday.

Mars' dusty and windy environment makes it an ideal planet for the formation of sand dunes. However, upon closer inspection, it became apparent that these dunes are not perfectly circular. "They are still slightly asymmetrical, with steep slip faces on the south ends. This indicates that sand generally moves to the south, but the winds may be variable," said McEwen.

The HiRise camera is managed by the University of Arizona and was used by the Mars Reconnaissance Orbiter (MRO) to capture images of the dunes in late November of the previous year. The purpose of the research was to observe seasonal changes in frost coverage in the area, and the absence of frost is evident in the image.

This image is part of a series of photographs to monitor how frost disappears in the late winter on Mars, this observation appeared to be free of frost. A previous image showed when the surface was covered by frost.

Although Mars' landscape appears alien, these images demonstrate a connection between our two planets. Earth also boasts picturesque dunes that reveal similar stories of wind and seasonal changes. Both planets have their own unique beauty to be appreciated.