NASA's Curiosity looks for new clues

NASA's Curiosity rover is searching for an area called Gediz Vallis to determine when the surface of Mars was dry. Mars was once full of water and was warmer than it is now. Geddys Wallis looks like it was designed by the river a long time ago.

This excites scientists because they want to know how the river carved the channel. Because of the steep edges, they don't think wind created it. They speculate that it may have been carved by a flood or a river carrying rocks and sediments. After the waterway was formed it was filled with large stones and other debris. Scientists are interested in knowing whether a dry avalanche or a flood caused all this.

Curiosity has been climbing Mount Sharp, a massive mountain on Mars, since 2014. It took millions of years for the lower part of the mountain's layers to form. They provide clues about the history of Mars, particularly about the evolution of the planet's water content and the elements necessary for life. Curiosity discovered clay minerals in a layer that previously indicated high water content. It examines a layer of sulfate or salt minerals, usually left behind after water evaporates.

This takes several months, and the results will help scientists understand the timeline for mountain formation.

Erosion gradually removed layers of wind- and water-absorbed sediments from the lower part of Mount Sharp, exposing the layers visible today. This process took some time to complete, during which time the surface of Mount Sharp was desert-like and dry.

It was probably after these activities that the Geddis Wallis Channel was formed. The rocks and debris that later filled the canal are thought to have come from higher up the mountain, beyond Curiosity's grasp. It provides clues to the minerals present at the height of Mount Sharp.

Curiosity's project scientist, Ashwin Vasavada, Explains If the channel and its debris were formed by liquid water, it would be buoyant. This means that after a long dry spell, water has returned to Mount Sharp in large quantities.

This explanation fits with one of Curiosity's findings: water appears to have gradually come and gone, rather than gradually disappearing as the planet dries out. Mud fissures, shallow saltwater lakes, and the massive debris piled up directly beneath the channel to form the sprawling Geddy Wallis Ridge are all examples of these cycles.

Curiosity used the left navigation camera on the rover to capture a 360-degree black-and-white panorama of the channel. The image, taken on February 3, the 4,086th Martian day, depicts a pile of debris building behind one side of a sand and dark sand canal. The other side of the steep mountain that Curiosity climbed to get here.