Capture formation of the Moon. Illustration of three stages (from top to bottom) in the capture theory of the formation of the Moon. This theory states that the Moon formed separately from the Earth and was later captured to form a stable Earth-Moon system. Current theory rejects this and states that the Moon formed following an impact event soon after the Earth formed. For a series of illustrations of moon formation theories, see images C047/7687 to C047/7698.