No, this isn’t a firework. 🎆 You are looking at a flame and the glowing soot clusters it produced aboard the International Space Station (ISS). These yellow soot clusters grow larger than those on Earth, because they stay inside the flame longer in microgravity. This flame was one of many ignited inside a combustion research facility to investigate the amount of soot that is produced in different conditions. Soot is the carbon residue left behind when organic matter (or other carbon-containing material) doesn’t fully burn. It causes environmental and health issues, but can be helpful in multiple ways, including by enhancing radiant heat. This experiment could allow the design of flames that are more sooty or soot-free. These results may help create burner designs which are more efficient and less polluting. Credit: NASA #flame #space #microgravity #heat