Geological Chronicle
Hermite is a lunar impact crater located along the northern lunar limb, close to the north pole of the Moon at a latitude of 86° N. Spanning 108.64 kilometers in diameter, it formed roughly 3.91 billion years ago during the Nectarian period of the lunar geologic timescale. Viewed from Earth nearly from the side, the crater is illuminated by oblique sunlight. Past impacts have left Hermite worn and eroded, with a rugged outer rim that is notched and incised. To the west is Rozhdestvenskiy, to the south are Lovelace and Sylvester, and a pair of small craters sit along the southern rim. Grignard is incised into the southwest rim, where an overlying crater has merged with Hermite to share a common interior floor. The resurfaced interior floor forms a wide plain marked by low hills, numerous tiny craterlets, and a small crater near the northeastern wall.
In 2009, NASA's Lunar Reconnaissance Orbiter discovered that Hermite is the coldest place recorded in the Solar System, with temperatures at 26 K (−247 °C; −413 °F). For comparison, Pluto's surface only gets down to about 43 K (−230 °C; −382 °F). Attached to Hermite's northwest rim is the small crater Aepinus, which measures 16.74 km (10.40 mi) in diameter. On average, the rim of Aepinus receives illumination from the Sun 86.08 percent of the time, the highest on the Moon, which could make it a useful location for a moonbase. The crater was unnamed until the IAU designated it alongside 18 other craters on January 22, 2009, naming it after German-Russian astronomer Franz Aepinus.
Satellite craters near Hermite follow the convention of placing the identifying letter on the side of the crater midpoint closest to Hermite, though Hermite B remains an unofficial designation that has not been approved by the IAU. Within Hermite A's permanently shadowed region, where no light from the Sun ever reaches, a 2016 study published by the IEEE reported that roughly two-thirds of the crater's permanently shadowed region is covered with varying amounts of ice. A 2018 study also published by the IEEE countered this claim, arguing that the method used to detect ice in the earlier study was not refined enough to conclusively identify a material as ice, and that more detailed methods were needed to determine if ice exists within Hermite A. A 2022 analysis using data from the Chandrayaan-1 and Chandrayaan-2 lunar orbiters found that ice may exist in clusters on the walls and some parts of the floor of Hermite A. Hermite was named for French mathematician Charles Hermite, whose name was introduced into lunar nomenclature by David W. G. Arthur and Ewen Whitaker with the Rectified Lunar Atlas in 1963, before official adoption by the International Astronomical Union in 1964.