Geological Chronicle
Milne is a large peak ring basin in the southern hemisphere on the far side of the Moon, measuring 259.97 kilometers in diameter. Formed during the Pre-Nectarian period, the structure lacks a central peak and instead features an interior topographic ring. Situated northeast of Mare Australe and southeast of Lacus Solitudinis, the basin has undergone extensive erosion that reduced most of its outer perimeter to a low, irregular ridge line.
Successive impacts have significantly altered the basin floor and margins. The southern rim was obliterated and is overlain by the satellite craters Milne M and Milne N, the latter possessing a Copernican ray system and an extremely high rockfall density. On the basin interior, infrared spectral measurements have identified pure crystalline plagioclase across the relatively flat floor.
The interior floor contains several prominent impact structures, including Milne K south of the midpoint and its overlapping neighbor Milne L, which exhibits a very high rockfall density. A tight cluster of 10 to 12 small impact craters occupies the northeastern floor, while the northwestern rim is breached by the crater Scaliger, which spread ejecta across the adjacent terrain. The basin is named for British mathematician and astrophysicist Edward Arthur Milne.