Ball Lightning Observation at Uppsala, Sweden (1994)

In 1994, a ball lightning sighting was reported at Uppsala, Sweden — the historic university city north of Stockholm. The observation occurred during a thunderstorm and described a luminous sphere approximately 15 centimeters in diameter that entered a building through a window, traveled through a room at slow speed, and exited through the opposite wall, leaving a small scorch mark. The Uppsala case attracted the attention of researchers at Uppsala University, which has a long tradition of atmospheric and electrical research dating back to Anders Celsius in the 18th century. Swedish researchers have maintained an interest in ball lightning due to Scandinavia's intense auroral and electrical activity, and the Uppsala sighting contributed to a Nordic database of ball lightning observations. The report's credibility was enhanced by the physical evidence — the scorch mark on the wall provided tangible proof that something had traversed the room — and by the witness's detailed account of the sphere's appearance, trajectory, and duration.