Cracks in the Moon

Observations by an orbiting spacecraft suggest that one of the large volcanic plains on the Moon may have formed when the Moon's early crust cooled and contracted. That caused the crust to crack, allowing molten rock to bubble up to the surface, filling lower terrain and creating the Ocean of Storms. That origin would be difference from most of the dark volcanic plains, which formed after impacts by large asteroids. This image combines a Lunar Reconnaissance Orbiter view of the Ocean of Storms with an artist's depiction of the cracks around its edges. [NASA/Colorado School of Mines/MIT/JPL/GSFC]