Untitled, by South African artist Gavin Jantjes, is one of the works in the "African Cosmos" exhibition. National Museum of African Art hide caption

itoggle caption National Museum of African Art

An artist's impression shows a planet, right, orbiting the star Alpha Centauri B, center, a member of the triple star system that is the closest to Earth. ESO/L. Calcada/AP hide caption

itoggle caption ESO/L. Calcada/AP

A fragment of the meteor that crashed into Tissint, Morocco. Mark Mauthner/Heritage Auctions hide caption

itoggle caption Mark Mauthner/Heritage Auctions