For the first time, scientists have captured the invisible ultraviolet light that trees emit during thunderstorms. This eerie glow is happening above forests around the world every time a storm rolls in.
This phenomenon, called a corona, was previously just a theory. But recently, a team of researchers set out to prove it. Meteorologists had long suspected that trees emit faint bursts of ultraviolet light during electrical storms, but they needed confirmation. A study published in Geophysical Research Letters details how thunderstorms create electrical currents in trees. These currents travel up through moist trunks and branches, building up until they escape from the tips of leaves as a soft glow.
Patrick McFarland, a meteorologist at Pennsylvania State University, led the study. He explained how they observed this glow: “These things actually happen; we’ve seen them; we know they exist now.”
To gather evidence, the team started indoors, placing small trees beneath charged metal plates to simulate a storm. They could barely see the corona under the right conditions—a faint blue light under complete darkness.
The real challenge was capturing this light outdoors during an actual thunderstorm. They modified a Toyota Sienna with tools like a weather station and an ultraviolet-sensitive camera. When they filmed during storms, they recorded over 40 distinct bursts of ultraviolet light in just a few minutes. These bursts lasted between 0.1 and 3 seconds, appearing randomly across the leaves.
Each burst emits about 100 billion photons, suggesting this might be happening in forests everywhere during storms. McFarland noted, “I believe you’d see this glow on the top of every tree under the thunderstorm. It’d probably look like a cool light show—like thousands of UV-flashing fireflies!”
While visually stunning, there are concerns about what this means for trees. Repeated electrical surges might harm the branches, similar to lightning striking. Additionally, the corona effect could impact the atmosphere. It might affect how hydrocarbons emitted by trees are processed and could even play a role in thunderstorm electrification.
Experts emphasize that as thunderstorms become more frequent due to climate change, understanding these effects is vital. This isn’t just a fascinating natural event; it shapes our forests and skies in ways we are just beginning to comprehend.
This research aligns with other findings about climate change’s impact on weather patterns. For example, a report by the National Oceanic and Atmospheric Administration (NOAA) stated that the frequency and intensity of thunderstorms have increased in recent decades.
Overall, the corona phenomenon reveals deeper connections between weather, trees, and our atmosphere. It invites us to rethink how we view storms and their effects, making it a topic worth exploring further.
