We may finally have a full explanation into how will ‘o wisps work. We knew methane and other swamp gasses were involved, but how did they ignite?
As with the static electricity produced by stroking hair, fur, or carpet in the right conditions, the microlightning results from a buildup of opposing charges until the field created is strong enough to make them leap a gap.
High-speed imaging reveals the source of the charge as the surface of tiny bubbles of methane, which become either positively or negatively charged as they move through water, split, and combine. The charge concentration appears to survive the bubbles’ escape to the air. When the spark jumps the gap between a neighboring positive and negatively charged bubble, it leads to non-thermal oxidation, releasing energy from the chemical reaction between methane and oxygen, but mostly as blue-violet light rather than heat.