From the top of a thundercloud, lightning can erupt not downward but upward, racing toward the edge of space. These events, known as gigantic jets and sprites, bridge the gap between storm tops and the thin air of the upper atmosphere. They form when the electric field inside a storm grows strong enough that a normal cloud‑to‑ground strike is blocked or diverted, and charge instead finds a path into the sky above.
In that region, the air is sparse and partially ionized, a layer scientists call the ionosphere. There, electrons and ions respond quickly to intense electric potential, allowing upward lightning channels to grow tens of kilometers long. Gigantic jets resemble high‑voltage streamers in a laboratory discharge tube, a macroscopic cousin of dielectric breakdown driven by strong electric fields. Sprites, by contrast, appear as diffuse red flashes, triggered by the sudden change in electric charge after a powerful conventional strike below.
High‑speed cameras, photometers and radio antennas now track these transient luminous events with millisecond precision, revealing structures such as streamers, leaders and glow regions that mirror textbook plasma physics. Their energy budget is small compared with major ground strikes, yet their vertical reach means they interact directly with atmospheric chemistry and the global electric circuit, turning thunderstorms into occasional, momentary launchpads for lightning that touches near‑space.
