Colliding Planets (IMAGE) University of Warwick Caption The host star is running out of hydrogen in the core, swells up, and its surface becomes cooler. It is also losing mass, which causes the planets to move further out. The perturbation of the orbits may lead to collisions that will generate large amounts of rocky debris. Credit © Mark A. Garlick / <a href="http://www.space-art.co.uk">space-art.co.uk</a> / University of Warwick Usage Restrictions Images were all created for the University of Warwick by the space artist Mark A. Garlick and are free for use by media or the University but are otherwise copyright as follows: "© Mark A. Garlick / <a href="http://www.space-art.co.uk">space-art.co.uk</a> / University of Warwick" 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.