Caloris Planitia

Caloris Planitia

Mosaic of the Caloris basin based on photographs by the MESSENGER orbiter.
Location	Raditladi quadrangle, Mercury
Coordinates	30°30′N 189°48′W / 30.5°N 189.8°W / 30.5; -189.8
Diameter	1,550 km (963 mi)
Eponym	Latin for "heat"

Caloris Planitia /kəˈlɔːrɪs pləˈnɪʃ(i)ə/ is a plain within a large impact basin on Mercury, informally named Caloris, about 1,550 km (960 mi) in diameter.^[1] It is one of the largest impact basins in the Solar System. "Calor" is Latin for "heat" and the basin is so-named because the Sun is almost directly overhead every second time Mercury passes perihelion. The crater, discovered in 1974, is surrounded by the Caloris Montes, a ring of mountains approximately 2 km (1.2 mi) tall.