noun
- narrow valleys or channels on the surface of the Moon, formed by ancient lava flows or collapsed lava tubes
Usage: astronomy; geology
Examples
- The Apollo astronauts photographed several prominent rilles during their lunar missions.
- Hadley Rille was explored by the Apollo 15 crew in 1971.
- These rilles provide evidence of the Moon’s volcanic past.
- Scientists study rilles to understand lunar geological processes.
- The sinuous rilles snake across the lunar surface like dried riverbeds.
- Straight rilles appear to be fault-related features on the Moon.