A Martian Milestone Captures a Mysterious Dark Spot

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Yesou’re looking at a dark, volcanic expanse of Mars, known as Syrtis Major, that stretches some 800 miles across. This image was captured with color filters to highlight the grainy details of these dunes and sand plains, among the oldest ever discovered on the Red Planet. Syrtis Major is the Greek name for the Gulf of Sirte on the North African coast, which also has a triangular shape, and translates to “the great sandbar”.

This is the 100,000th image taken by the HiRISE, or High-Resolution Imaging Science Experiment, camera aboard NASA’s Mars Reconnaissance Orbiter. It was filmed in October and released last month. Such a specific view will help identify the origin of the sand that is whipped by the wind and transformed into dunes, which may emerge in part from the dark, weathered basalt rocks of the area.

NASA’s Mars Reconnaissance Orbiter was launched in 2005 to search for clues that water may have flowed long enough on the Red Planet to support life – a mystery that remains unsolved. Over the past two decades, HiRISE has provided a detailed overview of hundreds of points on the Martian surface. In fact, the sophisticated camera can capture surface features as small as a kitchen table.

Read more: “The moss that could terraform Mars”

All of this resulted in sharp views of many different Martian scenes, including the remains of gaseous eruptions and impact craters. These images allow scientists to track surface transformation over time and search for possible landing points and ice deposits to aid future human missions.

HiRISE captured this specific site thanks to a recommendation from a high school student in Colorado: Anyone can suggest a location on Mars for the team to view on this website. “One hundred thousand images like this have made Mars more familiar and accessible to everyone,” HiRISE principal investigator Shane Byrne said in a statement.

Now you can help the HiRISE team decide where to point their powerful camera and help illuminate Mars’ past and future.

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Main image: NASA/JPL-Caltech/University of Arizona

• Molly Glick

  Published on January 5, 2026

  Molly Glick is the newsletter editor of Nautilus.