--- title: "Scientists Baffled By These Almost Perfectly Circular Dunes on Mars" description: "NASA's Mars Reconnaissance Orbiter has spotted some dunes that are practically perfect circles. So the question remains: how did they form?" date: "2023-03-15" modified: "2023-03-15" authors: - name: "Frank Landymore" job_title: "Contributing Writer" link: "https://futurism.com/authors/flandymore" url: "https://futurism.com/the-byte/perfectly-circular-dunes-mars" categories: - "Astronomy" - "Mars" - "Space" tags: - "hirise" - "mars" - "NASA" - "the digest" --- # Scientists Baffled By These Almost Perfectly Circular Dunes on Mars ![NASA's Mars Reconnaissance Orbiter has spotted some dunes that are practically perfect circles. So the question remains: how did they form?]() *\Image: NASA\* ## Mars Donuts Mars is chock full of [beautiful sand dunes]() that can come in some truly [magnificent shapes and patterns]() that, sometimes, seem to defy explanation. Take a look at [these almost perfectly circular sand dunes]() dotting the Martian landscape that were spotted by NASA's Mars Reconnaissance Orbiter (MRO). According to a [description]() from the University of Arizona, which is leading the team behind the MRO's onboard High-Resolution Experiment (HiRise) camera that captured the images, the "almost perfectly circular" dunes are "unusual" and stick out like a sore thumb. Note the "almost" perfectly circular. According to the university, the dunes have a steep, downward slope known as a slip face on their southern ends, meaning that its sands are likely blown southward by the Martian winds. The planet's winds, however, are notoriously variable, which is only adding to the mystery. Regardless, with such slight asymmetries, you'd be forgiven for thinking the dunes were simply the result of a [crater illusion](). https://twitter.com/HiRISE/status/1631293804794847240 ## Written in the Sand These images were taken as part of an ongoing effort to monitor the receding frost as the Martian winter enters its final stages. The cycle of seasons on Mars is actually fairly similar to our own, even though a Martian year is considerably lengthier at 687 Earth days. Of particular interest to planetary scientists is Mars' northern hemisphere, where these dunes were photographed free of ice. An earlier image, though, shows their surfaces clearly permeated by frost. These circular dunes aren't the only strange dunes scientists have found so far on the Red Planet. In 2016, NASA's Curiosity rover [spotted ripple structures in large Martian sand dunes]() arranged in a pattern that researchers said is not found on Earth. Dunes continue to be an object of both fascination and of meticulous study for planetary scientists, as their malleable yet slowly shifting forms make them almost like geological footprints of the planet's wind and atmosphere. One of the [most comprehensive studies on Martian dunes]() to date tracked nearly 500 of them using the HiRise camera, and discovered that Martian dunes move only at a meager rate of two feet per year, a snail's pace compared to some on Earth that move over 100 feet. **More on Mars:** *[Scientists Figured Out Why Mars’ South Pole Looks Like Swiss Cheese]()* ## Author At Futurism, my work has often centered on bringing a sense of clarity and insight to complex topics ranging from the regulation of emerging technologies to the esoteric ideologies of Silicon Valley executives, while striving not to lose the poetic sense of awe inspired by often-obscure fields like astrophysics and quantum computing. I broke the story of CNET using AI to produce articles that turned out to be riddled with factual errors and plagiarism — a dam-breaking inflection point, as I've reported, that's inspired copycats and endless discourse while beguiling stakeholders ranging from tech giants to purveyors of spam around the web. My work at Futurism has been cited by publications including CBS News, the Los Angeles Times, Vice, Gizmodo, Engadget, the Verge, and Vanity Fair. I grew up in locales ranging from India to China, and now live in the exotic suburbs of Virginia. In my free time, I'm an avid reader of weird sci-fi literature, an aficionado of East Asian cinema, and, regrettably, a relapsed gamer. Allegedly, I’m working on a debut novel, currently untitled. ### Author social links [Bluesky]()