August 10, 2021
On the day you were born, another consciousness opened inside the cosmos and began taking notes.
Fire in Space
Birthday · August 10, 2021
A little universe, just for you
Your date.
Ready to give.
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APOD published August 10, 2021. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.
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.