Can fire exist in zero gravity?

Answer 1

Yes, fire can exist in zero gravity. And it's amazing to see. At least on a small scale. There was a real fire aboard the Mir space station, and it burned as predicted - in a sphere around the fuel source. A candle was lit aboard Mir and it burned with the faintest blue color, but the cameras could not see this. A match was also lit in the space station as a test. You can see a 5-second clip of a flame in zero gravity on YouTube, and a link is posted below.

Answer 2

When something burns, like a candle for instance, the substance acting as the fuel (e.g. the wax) becomes very hot and vapourises. Because the vapour is hot, and expands, it has a lower density than the surrounding air so it rises upwards. As it rises it mixes with oxygen in the air and the mixture burns. The hot gases produced continue to rise out of the way, and the extra heat produced vapourises more fuel so that the process can continue. But in space, where there is no gravity, there is also no density gradient so the hot gases can't rise. Instead they accumulate in place and starve the flame of a supply of fresh air, so it goes out. The only way to maintain a flame is to artificially blow in oxygen to ensure that there is sufficient to support combustion.

Answer 3

Yes, fire can exist in zero gravity. In such conditions, the lack of gravity does not prevent combustion from occurring since fire is a result of a chemical reaction between fuel and oxygen. However, the flame shape and behavior may be different compared to fire in normal gravity conditions.