Research

Ancient crater may be clue to Moon’s mantle

Among the largest known craters in the solar system

Red areas on the topographic image indicate high elevations, and blue or purple areas indicate low elevation. The South Pole Aitken basin could hold clues about the composition of the Moon’s mantle. Credit: NASA/GSFC

A massive impact on the Moon about 4 billion years ago left a 2,500-mile crater, among the largest known craters in the solar system. Smaller subsequent impacts left craters within that crater. Comparing the spectra of light reflected from the peaks of those craters may yield clues to the composition of the Moon’s lower crust and mantle — and would have implications for models of how the Moon formed.