3. The Blue Lightning of Mount Vesuvius (1906)
Observers saw an amazing show of blue lightning inside the volcanic plume in April 1906 as Mount Vesuvius erupted violently in Italy. Now known as volcanic lightning, this unusual event produced an amazing and terrible show as blue bolts swept the ash-filled heavens. The strength and colour of the lightning, which seemed to come from the very centre of the eruption, stunned both residents and scientists. One of the first well-documented instances of blue lightning linked to volcanic activity, this event spurred scientists to look at the special circumstances under which this phenomena occurs. Later studies showed that powerful electrical fields produced by the collision of ash particles and ice crystals within the volcanic plume might cause lightning discharges. The blue hue was ascribed to specific gases and particles in the volcanic eruptions. Mount Vesuvius’s Blue Lightning not only gave volcanologists useful information but also motivated writers and artists, therefore securing its position in both scientific publications and cultural memory.
4. The Blue Jet of 1989
Pilots flying over the Caribbean noted in 1989 seeing an odd upward-moving blue lightning bolt that seemed to link the top of a thundercloud to the edge of space. One of the first recorded views of a phenomena now known as a “blue jet,” this one Blue jets from the tops of thunderclouds reach altitudes of up to 50 km, unlike conventional lightning that hits downward. The 1989 occurrence challenged the accepted wisdom on atmospheric electricity by offering unambiguous proof of electrical activity occurring above thunderstorms. Based on this observation, researchers started focused studies to investigate these elusive events, which resulted in the identification of various high-altitude electrical discharges including sprites and elves. The Blue Jet of 1989 underlined the complexity of Earth’s electrical environment and established a new avenue of research in atmospheric physics, thereby implying still much to learn about the weather systems of the planet and their interaction with the upper atmosphere.