Astronauts lighting fuels in space see a bizarre result when the fire goes out.
Most people were taught as kids not to play with fire. However, aboard the International Space Station, that’s exactly what astronauts are doing. Since 2009, space station astronauts have tested new flame-extinguishing techniques with the goal of improving firefighting methods both in space and on Earth. Known as the Flame Extinguishment Experiment, or FLEX, a droplet of fuel is added and ignited inside a controlled combustion chamber. Due to the lack of gravity, a flame forms in the shape of a ball. The flame reaches temperatures between 2,200 and 3,100 degrees Fahrenheit before it is put out. But then, under certain conditions, something unexpected happens. With no flame visible, unused fuel in the chamber suddenly begins to glow. Burning at 400 to 1,000 degrees Fahrenheit, the result is what scientists call a cool flame. Watch the videos to see the experiment in action and to learn more about how flames behave and burn in space.