Gallery: Bizarre Dunes on Mars

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Say the word "dunes" and the image that likely comes to mind is the sort of features you'd see in the Sahara Desert; huge mounds of carmel-colored shifting sand. But on Mars, dunes take on an entirely different connotation, and with the orbital eyes of the HiRISE camera on the Mars Reconnaissance Orbiter, we've seen some pretty bizarre-looking dunes. Take the image above for example, a newly released photo of well-speckled dunes in Mars' north polar region. In this image, taken during the northern spring season, the dunes and ground are still covered in seasonal frost. "The speckled appearance is due to the warming of the area -- as the carbon dioxide frost and ice on the dunes warms, small areas warm and sublimate (turn from solid to gas) faster, creating small jets that expose/deposit dark sand and dust onto the surface," writes Serina Diniega on the

HiRISE website

. "Notice that there are no spots on the ground between the dunes -- that is because the ground stays more uniformly cold, unlike the darker dune sand."

See below for more weird dunes on Mars.

[caption id="attachment_93717" align="aligncenter" width="580" caption="Dunes in Aonia Terra on Mars. Credit: NASA/JPL/University of Arizona"]

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These dunes look as through someone has thrown a rippled blue-toned cloth across Mars' surface. HiRISE is monitoring these dunes in Aonia Terra for changes such as gullies, which form over the winter from the action of carbon dioxide frost. This image was taken on January 18, 2012 here on Earth, but the season in on Mars where this was taken was late fall in the Southern hemisphere. "Frost is just starting to accumulate here, and is concentrated on pole-facing slopes and in the troughs between the meter-scale ripples," wrote HiRISE Principal Investigator Alfred McEwen.

[caption id="attachment_93718" align="aligncenter" width="580" caption="Dunes in Russell Crater Dunes on Mars. Credit: NASA/JPL/University of Arizona"]

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[caption id="attachment_93719" align="aligncenter" width="580" caption="Pink dunes with black polka-dot speckles. Credit: NASA/JPL/University of Arizona"]

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[caption id="attachment_93720" align="aligncenter" width="386" caption="A wide area of dunes in Terra Cimmeria look as if they are being viewed under water. Credit: NASA/JPL/University of Arizona"]

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[caption id="attachment_93721" align="aligncenter" width="580" caption="Fans and polygons on Dunes. Credit: NASA/JPL/University of Arizona"]

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[caption id="attachment_93722" align="aligncenter" width="580" caption="Dark sand dunes at high Northern latitudes on Mars are covered seasonally by a layer of condensed carbon dioxide (dry ice), visible in this image. Credit: NASA/JPL/University of Arizona"]

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[caption id="attachment_77148" align="aligncenter" width="500" caption="Chocolate dunes? Credit: NASA/JPL/University of Arizona"]

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See more great images from Mars on the

HiRISE website

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com