A Son of the Rock

Fire is an odd, complicated chemical phenomenon. When in orbit round Earth it becomes even odder.

In a gravity well gravity shapes the flame to the familiar cone-like contours we can see flickering, ushering oxygen to the bottom of the fire, the product gases rising from the flame due to their lower density.

In orbit, when bodies are in free-fall (not “weightless”: the gravity is still there, only cancelled out by forward movement round the Earth, the link calls that situation microgravity) there is no bottom to the flame; oxygen is attracted from all sides and the fire becomes spherical.

Thsi image is from Astronomy Picture of the Day for 10/8/21.

I wouldn’t have liked to try that out, even if it is in a controlled environment. Fire in a spaceship must be like one on a sea-going vessel; the crew’s worst nightmare.