Image of Mars (IMAGE) U.S. National Science Foundation Caption Mars likely developed in two to four million years; Earth's growth was over 50 to 100 million years. Credit Christopher Leather/University of Chicago 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.