What Is a Rill On the Surface of the Moon and How Were Lunar Rills Formed?

Rills are extended crevices on the Moon’s surface.

They can run up to at least 150 miles (250 km) and over a mile (1.6 km) wide.

The thousands of rills that cut through the Moon’s terrain were probably formed from channels of molten lava.

In fluvial geomorphology on earth, a rill is a narrow and shallow incision into soil resulting from erosion by overland flow or surface runoff.