Giovanni Battista Riccioli (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of 126 arguments concerning the motion of the Earth, and for introducing the current scheme of lunar nomenclature.

Biography

Riccioli was born in Ferrara, Italy. He entered the Society of Jesus on 6 October 1614. After completing his novitiate, he began study of the humanities in 1616, pursuing those studies first at Ferrara, and then at Piacenza.

From 1620 to 1628 he studied philosophy and theology at the College of Parma. Parma Jesuits had developed a strong program of experimentation, such as with falling bodies. One of the most famous Italian Jesuits of the time, Giuseppe Biancani (1565–1624), was teaching at Parma when Riccioli arrived there. Biancani accepted new astronomical ideas such as the existence of lunar mountains and the fluid nature of the heavens, and collaborated with the Jesuit astronomer Christoph Scheiner (1573–1650) on sunspot observations. Riccioli mentions him with gratitude and admiration.

Riccioli is a large lunar impact crater located near the western limb of the Moon. It lies just to the northwest of the even larger and more prominent crater Grimaldi. To the southwest are the craters Hartwig and Schlüter that lie on the northeastern edge of Montes Cordillera, the ring-shaped range that surrounds Mare Orientale. Due to its location, Riccioli appears strongly foreshortened from the earth and is viewed almost from the side.

Riccioli is older than the Orientale basin to the southwest because the ejecta from the impact that created the Orientale basin overlies the crater. This debris lies in ridges that regionally trend northeast-southwest, but trend in a direction parallel to Riccioli's northeast wall in that part of the crater. A system of rilles named the Rimae Riccioli lies across the interior, and crosscut the ejecta ridges. In the northern half of the interior, the dark covering of lava that resurfaced the floor is visible, and apparently covers some of the ejecta ridges and floods some of the rilles.