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Keyword: kunowskycrater

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  • Astronomy Picture of the Day - Striped Sand Dunes on Mars

    01/06/2021 3:30:58 PM PST · by MtnClimber · 11 replies
    APOD.NASA.gov ^ | 6 Jan, 2021 | Image Credit: HiRISE, MRO, LPL (U. Arizona), NASA; Processing: Włodek Głażewski; Text: Alex R. Howe
    Explanation: Why are these sand dunes on Mars striped? No one is sure. The featured image shows striped dunes in Kunowsky Crater on Mars, photographed recently with the Mars Reconnaissance Orbiter’s HiRISE Camera. Many Martian dunes are known to be covered unevenly with carbon dioxide (dry ice) frost, creating patterns of light and dark areas. Carbon dioxide doesn’t melt, but sublimates, turning directly into a gas. Carbon dioxide is also a greenhouse material even as a solid, so it can trap heat under the ice and sublimate from the bottom up, causing geyser-like eruptions. During Martian spring, these eruptions can...