Geological Chronicle
Stretching between Mare Tranquillitatis and Mare Vaporum, Rima Ariadaeus is a linear rille formed when a section of the Moon's crust sank down between parallel fault lines. The structural trough spans a length of 300 km and measures approximately 5 km in width, showing no trace of associated volcanism.
The ridges crossing the rille trough are offset by the faults, proving that the ridges are older than the faulting. Because so few craters appear younger than the faults and the edges of the trough appear crisp, the structure is considered an end member where only pure faulting is involved
An Apollo mission photograph of the rille later led to online claims that the feature represented a lunar fracture. Astronomer Paul Groot and NASA clarified that no scientific evidence supports a split Moon, noting that the rille is similar to geological faults on Earth