Chadwick is a lunar

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

that lies on the

far side ''The Far Side'' is a single-panel comic created by Gary Larson and syndicated by Chronicle Features and then Universal Press Syndicate, which ran from December 31, 1979, to January 1, 1995 (when Larson retired as a cartoonist). Its surrealisti ...

of the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width ...

's surface, just beyond the southwestern limb. It is located to the northwest of the crater De Roy, and was previously designated De Roy X before being given its current name by the

IAU The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

. This region of the lunar surface lies at the southern end of the ejecta blanket that surrounds the

Mare Orientale Mare Orientale (Latin ''orientāle'', the "eastern sea") is a lunar mare. It is located on the western border of the near side and far side of the Moon, and is difficult to see from an Earthbound perspective. Images from spacecraft have reve ...

impact basin. Chadwick is roughly circular with a sharp-edged rim. The inner wall is somewhat wider to the south-southeast, giving the crater a slight outward bulge toward De Roy. The rim has not been significantly worn, and is not marked by any impacts of note. The interior surface has a somewhat uneven appearance. This crater lies within the

Mendel-Rydberg Basin The Mendel-Ryberg Basin is a Nectarian impact basin on the southwestern limb of the moon. It is named after the crater Mendel on the west margin and the smaller crater Rydberg north of the center of the basin. The basin is due south of the lar ...

, a 630 km wide impact basin of

Nectarian The Nectarian Period of the lunar geologic timescale runs from 3920 million years ago to 3850 million years ago. It is the period during which the Nectaris Basin and other major basins were formed by large impact events. Ejecta from Nectaris form ...

age.

References

* * * * * * * * * * * * Impact craters on the Moon {{Craters on the Moon: C-F