NASA has published new photos taken by its venerable Mars Rover Opportunity, which after 14 Earth years and 5,000 Sols – Martian days – continues its scientific mission on the planet Mars. In the ancient valley called Perseverance Valley it found a soil with a texture that resembles certain very particular rock strips on some mountain slopes on the Earth. These formations can be created by cycles of freezing and thawing of moist soil or wind, downhill transport or other processes.