Candle Burning in Earth and Space

On Earth, a candle flame takes on that teardrop shape because hot air rises, pulling cooler air in at the bottom. But in the low-gravity environment of the International Space Station, there’s no “up” or “down” in the same way. As a result, the flame forms a more rounded, bluish shape.

Also, flames in microgravity often burn at lower temperatures and more efficiently, resulting in that cool blue hue.