Scientists have recently discovered a faint green glow called a 'Green Ghost' that appears high in the sky (about 90 km altitude) shortly after a powerful lightning-related event known as a sprite. This green light is linked to excited oxygen atoms in the upper atmosphere.

In this study, researchers observed a gigantic jet (GJ)—a rare lightning event that shoots upward toward space—from Taiwan on June 22, 2024. Two cameras, located at distant mountain observatories, captured the event at the same time. After the jet, they noticed a distinct green glow in the sky above the jet, between 80 and 100 km altitude.

By measuring the brightness and how quickly the glow faded, they found the behavior matched what’s expected from airglow—a natural emission from oxygen atoms high in the atmosphere. This green emission lasted about 0.6 seconds, consistent with how long excited oxygen atoms typically glow.

The findings suggest that the top of the gigantic jet reached into a region where it could energize oxygen atoms, creating the green light. This supports the idea that gigantic jets can trigger phenomena similar to sprites, contributing to our understanding of how lightning interacts with the upper atmosphere.