COSMIC CONNECTIONS

The Formation of Craters and Maria on the Moon

The physical features of lunar craters and maria show that they were formed by asteroids impacting the Moon’s surface at high speed. The crater labeled in the photograph, called Aristillus after a Greek astronomer who lived around 300 b.c.e., is 55 km (34 miles) across and 3600 m (12,000 ft) deep.