Planetary scientists have captured an image of semi-circular sand dunes on the surface of Mars. While dunes across the Red Planet come in a wide range of shapes and sizes, such well-defined circles are unusual.
The slight asymmetry in the dunes shows that their sides are steep to the south. University of Arizona administered HiRise experience The camera used to take the photo, indicated in statement (Opens in a new tab) That this indicates that the sands are blowing south, although the Martian winds may be variable.
The image was taken on November 22, 2022 at 42.505 degrees latitude and 67.076 degrees longitude. This comes as part of a series of images taken by the Mars-orbiting HiRise Camera aboard the Mars Reconnaissance Orbiter (MRO).
Related: Mars: everything you need to know about the red planet
The set of images is being used to observe how frost recedes and melts on Mars as the Red Planet reaches the end of winter. To be clear, while this image appears free of frost, a similar image of the same sand dune taken earlier shows what it looked like while it was still covered in frost.
The dune image was taken while MRO was about 185 miles (300 kilometers) above the surface of Mars. Each pixel in the image represents 25 cm (9.8 in).
This is just one of 60 locations on Mars monitored by HiRise. The high-resolution camera has been orbiting the Red Planet since MRO arrived at Mars in 2006 and began its first dedicated survey of the planet’s sand dunes.
Collecting repeated observations of the sand dunes over the course of a Martian year (it lasted 687 Earth days) allowed planetary scientists to monitor how fast the dunes were moving. This showed that dunes advance from the equator to the poles at rates of up to 3.3 feet (1 meter) per Martian year.
The camera recorded a variety of Martian sand dunes with an impressive array of both sizes and shapes, and they revealed a lot about weather conditions on the Red Planet. For example, while examining Lyot Crater in Mars’ northern lowlands in 2010, HiRise imaged dune fields that indicated how local winds are channeled through the complex 146-mile-wide (236-kilometer) impact crater topology.
HiRise also conducts ongoing research looking at glacier-like formations across Mars and examining fault-type fractures that punctuate their surfaces. By collecting repeated observations over time, the images can help scientists determine the type of fracture mechanics that occur in so-called “viscous flow features” found at the bases of slopes on Mars. It is believed that these deposits were once rich in ice, but the source of this ice is still a mystery until now. According to NASA. (Opens in a new tab)
On December 21, 2010, MRO’s primary mission ended five years and six months after its launch on August 12, 2005. This new image shows that even 12 years after the end of that mission, the science contribution made by the spacecraft and its camera HiRise is far from over.
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