Here’s what might spark ghostly will-o’-the-wisps
Jostling microbubbles of air and methane can create tiny lightning zaps, lab tests show
Glowing balls of bluish light have been seen above swamps and cemeteries around the world, as seen in this early 1800s engraving. Swamp will-o’-the-wisps are believed to be the burning of seeping methane gas. But what ignites that gas has been shrouded in mystery.
Grosvenor Prints (CC BY 4.0)