Alder (Moon)

Named after Kurt Alder - German organic chemist; Nobel laureate (1902-1958).

Alder is a lunar impact crater that is located in the southern hemisphere on the far side. It is located in the South Pole-Aitken basin, and lies to the southeast of the crater Von Kármán. Southeast is Bose, and to the south-southwest lies Boyle. The inner wall is rough and slightly terraced, with the material scattered across the edges of the otherwise flat interior floor. (wikipedia entry)

A crater is a circular depression likely created by an impact event. On the Moon they are named after deceased scientists, polar explorers, astronauts or cosmonauts.