Flame Design (IMAGE) NASA/Johnson Space Center Caption This flame was one of many ignited as part of the Flame Design investigation inside of CIR to investigate the amount of soot that is produced in different conditions. The yellow spots are soot clusters that glow yellow when hot. These clusters grow larger in microgravity than on Earth because the soot remains within the flame longer. Credit NASA 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.