A hit-and-run Giant Impact scenario
  The formation of the Moon from the debris of a slow and grazing giant impact of a Mars-sized impactor on the proto-Earth (Cameron & Ward 1976, Canup & Asphaug 2001) is widely accepted today. We present an alternative scenario with a hit-and-run collision (Asphaug 2010) with a fractionally increased impact velocity and a steeper impact angle. 
Andreas Reufer, Matthias M. M. Meier, Willy Benz, Rainer Wieler
astro-ph.EP