Traces of ancient ripples carved on Mars Photographed by NASA's Mars rover Curiosity

[▲ The surface of Gale Crater taken on December 16, 2022 using the Mars rover Curiosity’s camera “Mastcam” (Credit: NASA/JPL-Caltech/MSSS)]

This image was taken by NASA’s Mars rover Curiosity.December 16, 2022 (Mission 3684 Sol※) was taken.

* 1 Sol = 1 solar day on Mars, approximately 24 hours and 40 minutes.

The Gale Crater, which Curiosity has been exploring since landing in August 2012, is believed to have had a lake billions of years ago. According to NASA’s Jet Propulsion Laboratory (JPL), which operates Curiosity, the three-dimensional stripes carved into the surface of the Earth are believed to be ripple marks formed in ancient lakes. Such striped patterns were formed by waves standing at shallow water depths rolling up the sediment on the bottom of the lake. In other words, the streaks are evidence that Gale Crater once had liquid water.

[▲ A version with a scale bar added to the top image (unit: cm) (Credit: NASA/JPL-Caltech/MSSS)]

The discovery of stripes formed by waves on the surface of the lake surprised the Curiosity team. Sulfates, which are thought to have been left behind when the lake dried up, were present in the area, and it was thought that the rock layers around the shooting location were formed in the process of drying the Martian climate. “This is the best evidence of water and waves in the entire mission,” said JPL’s Ashwin Vasavada, the mission’s project scientist. There is nothing,” he said.

【▲ A selfie taken by NASA’s Mars rover Curiosity. Released on March 30, 2021 (Credit: NASA/JPL-Caltech/MSSS)】

Since 2014, Curiosity has been conducting exploration activities while gradually climbing Mt. Throughout the period when water existed on the surface of Mars, sediment carried by water into the interior of Gale Crater accumulated in layers from the bottom of the crater to the top, and was eroded at a later time. It is thought that the cross section became exposed at By studying the sedimentary rocks while climbing Mt. Aeolis, we will be able to trace time from ancient to newer times and gain information about how the ancient Martian environment changed over time.

[▲ “A Guide to Gale Crater” (English)]
（Credit: NASA/JPL-Caltech）

The first image was taken in an area known as the “Marker Band” and was released alongside a panoramic image created by stitching together images taken on the same day. The marker band appears darker than its surroundings when viewed from space, with a thin layer of rock covering the surface. This layer appears to be made of very hard rock, JPL says Curiosity’s drill was unable to sample the rock.

[▲ A panorama of the ‘Marker Band Valley’ created by stitching together multiple images taken on December 16, 2022 using the camera ‘Mastcam’ on the Mars rover Curiosity (Credit: NASA/JPL-Caltech/MSSS)]

The Curiosity mission, which celebrated 10 years since landing on Mars in August 2022, is still ongoing as of February 2023, and vigorous efforts are being made to collect samples of the surface and observe the atmosphere. A panorama of the marker band and an image of the stripes carved into the former lakebed have been released by JPL on February 8, 2023.

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