Why Candle Flames Point Up on Earth, and Turn Into Blue Spheres in Space
A candle flame tapers upward because hot air gets light and rises. In orbit, with no up or down, that air never rises, and the same flame settles into a flickerless blue sphere. Then there's the stranger part: on the ISS, researchers found fire that keeps burning invisibly after it looks like it has gone out, a phenomenon called a cool flame.
