Galaxies getting hotter with age (IMAGE) Johns Hopkins University Caption As the universe evolves, matter concentrations are surrounded by gas halos getting hotter and bigger. Credit D. Nelson / Illustris Collaboration 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.