The European Space Agency’s Mars Express orbiter has spotted what look like metallic waves rippling across the floor of a giant crater on Mars. The shiny, almost mirror-like ridges are actually sand dunes towering more than 100 meters high, their unusual gleam caused by frost deposits on their south-facing slopes.
The image, captured by the High Resolution Stereo Camera aboard the orbiter, focuses on Kaiser Crater, a massive basin about 180 kilometers across and several kilometers deep. The crater sits in Noachis Terra, one of the oldest regions on the Red Planet, located in the southern highlands. Over the past four billion years, this area has been heavily pounded by space rocks, leaving it scarred with craters of all sizes.
A landscape shaped by wind and water
Much of Kaiser Crater’s floor is covered by dark, wavy dunes that look almost carved from metal. These are not static features. Martian winds have sculpted them over time into two main types: barchan dunes, which are sickle-shaped and common in Earth’s Sahara and Namib deserts, and transverse dunes, which are longer and run parallel to each other. Both types form when sand builds up and is pushed by winds blowing consistently from the same direction. Some dunes stand alone, while others merge into a continuous field stretching for several kilometers.
The image also reveals a striking difference in elevation between the left and right sides, a direct result of the impact that created Kaiser Crater. A prominent ridge running down the middle of the picture marks part of the crater’s southern rim. To the left, a scattering of smaller craters shows varying ages: some have crisp, fresh edges, while others have been worn smooth over eons.
Nearby craters with human names
Several other notable craters lie just outside the frame, including Greeley, Le Verrier, and Neukum Craters. Neukum Crater is named after Gerhard Neukum, one of the planetary scientists who founded the Mars Express mission and led the development of its camera. All of these craters have been featured in previous Mars Express releases, highlighting the orbiter’s long-running survey of the planet’s surface.
This snapshot of Kaiser Crater offers a glimpse into a world where wind, water, and time have left their marks in ways that feel both alien and familiar. The dunes, gleaming with frost, stand as a reminder that even on a cold, dry planet, the forces of erosion and deposition continue to shape the landscape, just as they do on Earth.
