Earth is the only known planet where fire can burn. Everywhere else, there is not enough oxygen.
Oxygen supply influences the colour of the flame. A low-oxygen fire contains lots of un-combusted fuel particles and will give off a yellow glow, whilst a high-oxygen fire burns blue.
Candle flames are blue at the bottom because that’s where they take up fresh air, and yellow at the top because the rising fumes from below partly suffocate the upper part of the flame.
Conversely, the more oxygen, the hotter the fire. Air contains 21% of oxygen; combine pure oxygen with acetylene, a chemical relative of methane, and you get an oxyacetylene welding torch that burns at over 5,500 degrees Fahrenheit. This is the hottest fire you are likely to encounter.
The 1666 Great Fire of London destroyed 80% of the city, but also ended an outbreak of bubonic plague that had killed more than 65,000 people the previous year. The fire fried the rats and fleas that carried Yersinia pestis, the plague-causing bacterium.
