Fire in Space
What does fire look like in space? In the gravity on Earth , heated air rises and expands, causing flames to be teardrop shaped . In the microgravity of the air-filled International Space Station ( ISS ), however, flames are spheres . Fire is the rapid acquisition of oxygen, and space flames meet new oxygen molecules when they float by randomly from all directions -- creating the enveloping sphere. In the featured image taken in the ISS's Combustion Integration Rack , a spherical flame envelopes clusters of hot glowing soot . Without oxygen, say in the vacuum of empty space, a fire would go out immediately. The many chemical reactions involved with fire are complex, and testing them in microgravity is helping humanity not only to better understand fire -- but how to put out fire , too.