Key Takeaways
- Lightning bolts striking the ocean, known as “superbolts,” are brighter and more intense than those hitting land, yet the reason behind this phenomenon remained a mystery.
- Marine scientist Mustafa Asfur’s experiment using a simple setup revealed that lightning-like discharges over saltwater are significantly brighter than over fresh water or soil.
- The study challenges the belief that thunderstorm dynamics control lightning intensity, showing that the conductivity of water plays a pivotal role.
- Saltwater contains positive and negative ions that enhance electrical conductivity. When lightning strikes, the increased ion presence leads to a swifter discharge, resulting in a brighter flash.
- A global lightning survey discovered that intense superbolt distribution is prominent over oceans, notably in the Mediterranean Sea, while hints of potential connections to climate change and saltwater content arise.
In a fascinating revelation, marine scientist Mustafa Asfur unintentionally unraveled a conundrum that had puzzled researchers for years: the heightened brightness of lightning bolts over the ocean compared to their counterparts on land. Despite more than 90 percent of lightning strikes targeting continents, those hitting the ocean tend to be considerably more intense. These remarkable “superbolts,” flashes a hundred to a thousand times brighter and mightier than regular bolts, exhibit a greater likelihood of impacting oceanic expanses. The quest to comprehend this intriguing occurrence continues.
Asfur, now affiliated with the Ruppin Academic Center in Israel, initially embarked on an exploration of lightning bolts’ impact on water chemistry. However, his experiments uncovered a surprising insight: simulated lightning discharges were distinctly brighter over saltwater than over freshwater or soil. Colin Price, an atmospheric scientist from Tel Aviv University who supervised Asfur’s experiments, expressed astonishment at the unexpected results. While convention dictated that thunderstorm dynamics determined flash intensity, this study underscores the substantial influence of the medium beneath the storm clouds.
Asfur’s rudimentary experimental setup included a spark generator, electrodes, and a container of water housed in a dim wooden enclosure. Despite being millions of times less potent than natural lightning, the miniature bolts emitted the same light profile as genuine sparks.
The pivotal observation was that saltier water generated more radiant sparks. Subsequent trials utilizing samples from various water bodies, ranging from minimally salty to extremely salty, consistently illustrated that heightened salt content correlated with increased flash luminosity. The explanation rests on the propensity of salt in water to divide into positive and negative ions, facilitating electrical conduction. When lightning strikes, the augmented ion presence expedites charge dissipation, culminating in a brighter flash.
Notably, the investigation hints at a climate change connection. Areas of seawater are becoming saltier due to intensified evaporation in certain regions, while others are undergoing freshening due to melting ice. The surplus ions introduced by these changes could potentially lead to even more intense lightning displays—akin to “super superbolts.”
Despite this breakthrough, the complexities of lightning’s behavior remain enigmatic. Recent large-scale lightning surveys reveal that superbolts cluster predominantly over oceans, particularly in the Mediterranean Sea. However, the interplay of factors influencing bolt energy and overall brightness, as well as the interaction with climate change, remain puzzles waiting to be solved in the electrifying world of lightning phenomena.
Read full article at Smithsonian Magazine
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The incredibly rare moment a bolt of lightning hits the sea off the Dorset coast at Portland BillCredit: BNPS
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A bolt of lightning, 40 metres away (©Francis Schaefers and Daniel Burger)
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Lightning strikes really close to fisherman
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