Geological Chronicle
Bolyai is an old lunar impact crater in the southern hemisphere, on the Moon’s far side. Eötvös lies to its southeast and Neujmin to its north. Its diameter is 102.22 km.
Subsequent impacts heavily eroded the crater, leaving a deformed remnant of the original rim overlaid by many smaller craters. Bolyai D lies along the northeastern rim, while Bolyai W to the northwest is a formation of overlapping craters. The interior is relatively level but rough in places, with a rounded central peak.
From near the central peak toward the northern rim, part of the floor has been resurfaced by mare material. This area is smoother and has a lower albedo, giving it a dark appearance. Its surface dates to around 3.5 Ga. A cluster of small ridges in the mare’s western part is likely the result of compressional stresses. The International Astronomical Union formally adopted the designation in 1970. The crater is named after Hungarian mathematician János Bolyai (1802–1860).