![\"Microlightning](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2025\/09\/microlightning-might-p.jpg\" "\\"Microlightning")
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Microlightning between bubbles containing air and methane. Credit: Yu Xia<\/p>\n
For centuries, people have described strange blue balls of light floating around in marshes, wetlands, and even cemeteries. It’s no surprise that these mysterious flames, termed “will-o’-the-wisps” or ignis fatuus, have spurred countless ghostly explanations, but even the more scientific theories were speculative in nature and lacked experimental support.<\/p>\n
However, most scientists agree that these phenomena are somehow related to the methane<\/a> bubbling up from decaying organic matter in the ground. The ignition of the methane is still a mystery though, as there is no known natural process which can ignite methane at ambient temperatures<\/a>.<\/p>\n But now, a group of scientists, led by Richard Zare of Stanford University, think they may have an explanation. The group had previously studied a strange luminescence arising from charged microdroplets of water. Their previous work<\/a> was published in Science Advances.<\/p>\n They explain, “The close approach of oppositely charged microdroplets causes an electrical discharge and leads to luminescent emission. The light emission happens without any external voltage applied, and the electrical discharge is sufficiently energetic to excite, dissociate, or ionize surrounding neutral gas molecules.”<\/p>\n A movie showing multiple spontaneous discharge events (microlightning) occurring between adjacent methane\u2013air microbubbles under high\u2013density bubbling conditions. Credit: Proceedings of the National Academy of Sciences (2025). DOI: 10.1073\/pnas.2521255122 <\/p>\n They believe this kind of reaction might be the reason for the mysterious will-o’-the-wisps as well, since it could provide enough energy to ignite methane. To test the theory, the group used a submerged nozzle to generate methane\u2013air microbubbles in water and captured submillisecond flashes between bubbles with high-speed imaging, photodiode detection, and photon-counting devices.<\/p>\n They also used emission spectra, temperature monitoring, and mass spectrometry<\/a> to track any chemical and thermal changes during the experiment. A report of their work is now published<\/a> in the Proceedings of the National Academy of Sciences.<\/p>\n The experiment did indeed result in the same kind of spontaneous electrical discharges, or microlightning, that they found in their previous study. Although it now occurred between methane-containing microbubbles in water, generating brief flashes, initiating methane oxidation, and producing both light and heat at room temperature. The experiment may not provide hard evidence that this exact phenomenon is what occurs in the field to produce will-o’-the-wisps, but it provides a plausible, testable mechanism that may be the best explanation yet.<\/p>\n A movie showing a close-up view of two methane\u2013air microbubbles approaching and undergoing a microlightning event immediately prior to coalescence. Credit: Proceedings of the National Academy of Sciences (2025). DOI: 10.1073\/pnas.2521255122 <\/p>\n “Our findings offer a scientific basis for ignis fatuus and reveal a general mechanism by which electrified interfaces can drive redox reactions<\/a> in natural environments without the need for external ignition sources,” say the study authors.<\/p>\n The study not only sheds light on the mystery of will-o’-the-wisps from folklore, but also helps scientists better understand how naturally-occurring electrical phenomena can drive chemical reactions in natural environments<\/a>. Future efforts can quantify the scale and frequency of microlightning events in the wild.<\/p>\n \n Written for you by our author Krystal Kasal<\/a>, edited by Lisa Lock<\/a>, and fact-checked and reviewed by Robert Egan<\/a>\u2014this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
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