Question

What happens when a burning candle placed in zero gravity? Is it burn more vigorously or less vigorously....✊

Answer 1

 A candle can burn in zero gravity. However, the flame is quite a bit different. Fire behaves differently in space and microgravity than on Earth.
Microgravity Flames

A microgravity flame forms a sphere surrounding the wick. Diffusion feeds the flame with oxygen and allows carbon dioxide to move away from the point of combustion, so the rate of burning is slowed.