Geological Chronicle
Joule is a worn, eroded impact crater spanning 97.52 kilometers across on the far side of the Moon. Formed during the Imbrian or Nectarian period, it lies north-northeast of the walled plain Mach, with the crater Blazhko located to the northwest.
The crater's rim and inner walls are irregular, broken by a pair of smaller impacts along the northeastern rim and an intruding crater on the northwest margin. An outward projection to the south has the appearance of an older crater partly overlain by Joule. Infrared spectroscopy has detected the signature of pure crystalline plagioclase on the south wall.
The interior floor is more level than the surrounding terrain, marked by small craterlets and a central peak at its midpoint. Less than a crater diameter to the west lies Joule T, with the ray crater Wargo situated on its western edge. While Wargo's rays extend primarily southward across the crater Harvey, only faint traces enter Joule, restricted to the western rim, inner sides, and floor.