Copernican period

The Copernican Period in the lunar geologic timescale runs from approximately 1.1 billion years ago to the present day.

The base of the Copernican period is defined by impact craters that possess bright optically immature ray systems.

This definition, however, has recently been subjected to some criticism as some crater rays are bright for compositional reasons that are unrelated to the amount of space weathering they have incurred.

Large examples on the near side include Tycho, Aristillus, Autolycus, Stevinus, Kepler, Theophilus, Taruntius, Eudoxus, Bürg, Römer, Harpalus, Carpenter, Philolaus, Anaxagoras, Glushko, Hayn, Zucchius, and Rutherfurd.

Examples on the far side include Ohm, Jackson, King, Necho, Giordano Bruno, O'Day, Crookes, Robertson, Vavilov, and Sharonov.