NASA's orbiting HiRISE camera captured a Martian mystery

NASA's orbiting HiRISE camera captured a Martian mystery on June 10: What formed the intriguing mounds visible on the floor of a large, ancient crater?

The mounds may be ejecta from meteor impacts, lava laid down by volcanic eruptions, or fluvial sediments from a wetter, ancient Mars.

Although the question remains unanswered, scientists believe that the rough texture of the mounds means that the crater's bedrock surface has been eroded over time, perhaps by whipping Martian winds.