Why doesn't gravity act on fire?

 

Amazingly, gravity itself is the reason the flame rises up.

Look at the image below:

An elongated flame is observed when the candle burns in the presence of gravity. This is what we observe in everyday life, right? A spherical flame is observed in microgravity or in the absence of effective gravity.

Why did this happened ?

When the candle wick begins to burn from the combustion of fuel with oxygen, heat is released. This released heat heats the burning gases and combustion products. This hot air, which is less dense, rises and cold air rushes in to fill that vacant spot. Since cold air is heavier, it stays. This form of air movement is called convection and is what keeps the flame upright and elongated when the candle is lit in the presence of gravity.

When there is no effective gravity, while there is hot and cold air, and although both are more dense and less dense respectively, the absence of a net gravitational force means that there are no buoyant forces. Therefore, the shape of the flame remains spherical and radiates heat outwards in all directions.