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Metallic waves on ancient Mars

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@ 15/07/2026

Metallic waves on ancient Mars
This image from ESA’s Mars Express shows part of Kaiser Crater and its surroundings in Noachis Terra, one of the oldest parts of Mars. This image comprises data gathered by Mars Express’s High Resolution Stereo Camera (HRSC) on 5 October 2025 (orbit 27461). It was created using data from the nadir channel, the field of view aligned perpendicular to the surface of Mars, and the color channels of the HRSC. North is to the right. The ground resolution of the original image is approximately 17 m/pixel and the image is centred at about 48°S/19°E. Credit: ESA/DLR/FU Berlin

The European Space Agency's Mars Express has spotted a swath of metallic-looking waves filling Mars's large Kaiser Crater—an ancient and otherworldly dune field sculpted by wind.

This month's snapshot of Mars, taken by the High Resolution Stereo Camera (HRSC) aboard ESA's Mars orbiter, captures one of the oldest parts of the red planet: Noachis Terra. Situated in Mars's ancient southern highlands, Noachis Terra has been heavily bombarded with rocks from space over the past 4 billion years—and the scars from these collisions are clear to see.

This image is packed with impact craters. The right half of the image is dominated by part of the floor of the giant Kaiser Crater, a large basin that measures about 180 km (112 miles) across and a couple of kilometers deep. The prominent ridge running down the middle of the image marks part of the crater's southern rim.

On the left is a wide scattering of smaller craters, some with crisp edges and others that have been gradually worn away over time. The difference in elevation between the left and right sides of this image—a result of Kaiser Crater's formation—is marked and fascinating, and best seen in the associated topographic map below.

Metallic waves on ancient Mars
This color-coded topographic image shows part of the huge Kaiser Crater (right, in blues and greens), a smaller neighbouring crater, and their surroundings on Mars. It was created from data collected by ESA’s Mars Express on 5 October 2025 (orbit 27461) and is based on a digital terrain model of the region, from which the topography of the landscape can be derived. Lower parts of the surface are shown in blues and greens, while higher altitude regions show up in whites, pinks, and reds, as indicated on the scale to the top right. North is to the right. The ground resolution of the original image is approximately 17 m/pixel and the image is centred at about 48°S/19°E. Credit: ESA/DLR/FU Berlin

A number of notable craters also lie nearby but out of frame (see context map below), including Greeley, Le Verrier and Neukum craters. All of these craters have been the focus of previous Mars Express releases, and the last is named after Gerhard Neukum, one of the planetary scientists that founded the Mars Express mission itself and led the development of the spacecraft's HRSC.

Metallic waves on ancient Mars
This image marks the location of Kaiser Crater, a large crater in Mars’s ancient Noachis Terra. A large dotted square highlights the area of Mars featured in new images from the High Resolution Stereo Camera (HRSC) aboard ESA’s Mars Express, released in July 2026. The two smaller boxes within mark the precise patch of surface shown in the images, captured by Mars Express on 5 October 2025 (orbit 27461). The elevation of the surface, shown by the bright colors marking the surface of Mars, is indicated by the scale to the bottom-right. Credit: NASA/USGS; ESA/DLR/FU Berlin

Sandy waves shaped by water and wind

Much of the floor of Kaiser Crater is covered by distinctive, dark, almost shiny waves that look almost as if they're carved out of metal. These ridges are sand dunes that have been molded by Martian winds—they can tower more than 100 m (330 feet) above the surrounding surface. Some are more solitary and isolated, while others merge to form a continuous dune field that extends for several kilometers. Their shiny, slightly metallic appearance is caused by bright frost deposits on their south-facing slopes.

This dune field comprises a mix of "transverse" and "barchan" dunes. Barchan dunes are sickle-shaped; they are the most common type of dune found on Mars and are also prevalent in Earth's deserts (such as Africa's Sahara and Namib deserts). Also seen on our planet, transverse dunes are more elongated and parallel in their distribution, and can evolve as barchans accumulate more and more sand. Both types of dune are formed by sand building up and being swept about by winds blowing from the same direction.

Metallic waves on ancient Mars
Bird's eye view of wind-blown dunes in Mars's Kaiser Crater, generated from the digital terrain model and the nadir and color channels of the High Resolution Stereo Camera on ESA’s Mars Express. Credit: ESA/DLR/FU Berlin

The winds in this part of Mars blow predominantly from the west (top), pushing and moving sand around to form these distinctive wave crests. The sand itself is fine and basaltic in nature—meaning that it's rich in minerals such as pyroxene and olivine, which are formed by volcanoes—and is constantly in motion, causing these dynamic landforms to slowly change and evolve over time.

Metallic waves on ancient Mars
The floor of Mars’s Kaiser Crater from above, generated from the digital terrain model and the nadir and color channels of the High Resolution Stereo Camera on ESA’s Mars Express. Credit: ESA/DLR/FU Berlin

There are also signs of water-related activity here. Martian winds have stripped away the upper layers of the planet's surface in places, revealing light-toned clay rock that likely formed in the presence of water. There are also little gullies and narrow channels lining the steeper walls of some of the craters here—while these were likely formed by dry landslides slipping down unstable slopes, some of the older gullies may have formed as ice reserves melted, or buried groundwater reservoirs caused the ground above to shift.

Metallic waves on ancient Mars
Bird’s-eye view of craters in Noachis Terra, generated from the digital terrain model and the nadir and color channels of the High Resolution Stereo Camera on ESA’s Mars Express. Credit: ESA/DLR/FU Berlin

Decades of Mars exploration

Mars Express has been capturing and exploring Mars's many landscapes since it launched in 2003. The orbiter has mapped the planet's surface at unprecedented resolution, in color, and in three dimensions for more than two decades now, returning insights that have drastically changed our understanding of our planetary neighbor.

Who's behind this story?

Lisa Lock

Lisa Lock

BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021. Full profile →

Andrew Zinin

Andrew Zinin

Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →

Citation: Metallic waves on ancient Mars (2026, July 15) retrieved 16 July 2026 from https://phys.org/news/2026-07-metallic-ancient-mars.html

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