On June 30, 1908, a cosmic body—likely a comet or asteroid measuring roughly 100 to 200 feet across—exploded high above the Podkamennaya Tunguska River in remote Siberia. The blast generated energy equivalent to 10 to 15 megatons of TNT, flattening over 80 million trees across 800 square miles. However, the most haunting phenomenon for millions of people thousands of miles away occurred in the atmosphere.
The airburst injected vast quantities of fine dust, icy particulates, and ionized water vapor directly into the upper stratosphere and mesosphere, well above 50 miles in altitude. Prevailing high-altitude winds swiftly swept these micro-particles westwards across Asia and Western Europe. Over the next three nights, nightfall simply vanished from Russia to the British Isles.
The ice crystals suspended in the upper atmosphere acted as massive optical reflectors, scattering sunlight from around the curvature of the Earth back down to the ground. Observers in London, Paris, and Stockholm reported bright, shimmering noctilucent clouds and a surreal amber glow that rendered the night sky so bright that residents could effortlessly read fine print in newspapers at 2:00 AM without artificial light. Meteorologists of the era were baffled, as satellite tracking and real-time global communication did not yet exist to link the London twilight to the remote Siberian blast.