Impact simulation still (IMAGE) Durham University Caption Still image from a cross section of a 3D simulation run by researchers investigating how a collision between the early-Earth and a Mars-size object might have led to the formation of the Moon. Credit Sergio Ruiz-Bonilla Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.