NASA’s Curiosity rover has seen a lot of rocks. In fact, that’s almost all it sees on the surface of Mars. Recently, the rover spotted a rock so strange that the team decided to move in for a closer look. The so-called “Strathdon” has dozens of sedimentary layers squished together, a geological quirk scientists didn’t expect to see on Mars. This points to a potentially complicated and watery past in the region explored by Curiosity.
Curiosity landed on Mars in 2012, setting up shop in Gale Crater. Its goal was to make its way to nearby Mount Sharp and roll up the slope, examining the geology on the way. It reached the base of the mountain in 2014. The team has made numerous pit stops along the way to the summit in order to take a closer look at interesting regions. Currently, the rover is puttering around in an area called the “clay-bearing unit.” In the distant past, it was most likely home to streams and lakes, the only remnants of which are clay mineral deposits.
While exploring the clay-bearing unit, Curiosity happened upon a strange boulder partially buried in the ground — the Strathdon. The rock formed from many layers of compressed sediment that had hardened into a brittle, wavy mass. It’s a stark contrast from the flat layers of lake sediment Curiosity has seen elsewhere on Mars.
Curiosity approached the Strathdon, taking a close-up mosaic image for scientists back on Earth to examine. The team speculates that the structure of this boulder means the clay-bearing unit has a much more complex and dynamic geological history than anyone expected. A combination of flowing water and wind could be responsible for the existence of this formation. This region might have been quite hospitable to life many eons ago, but Curiosity can’t say for certain — that’s for the next rover to find out.
NASA’s Mars 2020 rover is being assembled at JPL as we speak. It has a robotic arm, wheels, and some of its many, many cameras. The still-unnamed rover uses the same chassis as Curiosity, but it will carry instruments that are better able to search for signs of ancient life on the red planet. The launch is scheduled for next summer when Earth and Mars are lined up for an easy journey. Mars 2020 will join Curiosity on the surface in February 2021.