Moon Formation (VIDEO) Carnegie Institution for Science This video is under embargo. Please login to access this video. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Caption A video simulation shows the canonical model of the Moon's formation, in which the proto-Earth was hit by a Mars-sized object between 4.4. and 4.5 billion years ago. Credit Courtesy of Miki Nakajima and Dave Stevenson. Usage Restrictions With credit 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.