Great balls of fire!...

OK - small balls of fire.

Flames are hard to understand because they are complicated. In an ordinary candle flame, for example, thousands of chemical reactions take place. Hydrocarbon molecules from the wick are vaporized and cracked apart by heat. They combine with oxygen to produce light, heat, carbon dioxide and water. Some of the hydrocarbon fragments form ring-shaped molecules called polycyclic aromatic hydrocarbons and, eventually, soot. Soot particles can themselves burn or simply drift away as smoke. The familiar teardrop shape of the flame is an effect caused by gravity. Hot air rises and draws fresh cool air behind it. This is called buoyancy and is what makes the flame shoot up and flicker.

Flame balls, on the other hand, are simple. The balls form in low gravity where turbulence and buoyancy have little effect. Oxygen and fuel combine in a narrow zone at the surface of the ball, not hither and yon throughout the flame. Once ignited and stabilized, their size remains constant. Unlike ordinary flames, which expand greedily when they need more fuel, flame balls let the oxygen and fuel come to them. Finally, the fact that flame balls are spherical reduces their dimension to one: the radius of the flame itself. [More]

Right - like you haven't wondered how a candle burns in space.

OK - maybe not.

[via Neatorama]