Scientists had long suspected methane had something to do with it. Turns out they were partly right.

Whatever the name, for centuries people have reported seeing these eerie, faint blue flames hovering over marshes, bogs and other wetlands. Scientists have offered a different explanation: they form ...

For scientists, though, one big mystery still remained. Although will-o’-the-wisps are not actual flames and occur at ambient temperatures, they still have to ignite somehow. The source of that ...