On February 6th, 2017, four detectors surrounding a nuclear power station in Niigata, Japan simultaneously observed a striking signal. An hour before dawn, the detectors recorded a short burst of light from a lightning strike, which quickly decayed in intensity, and was followed by an afterglow of radiation that lasted for about a minute.
These unique signals caused by lightning strikes have been predicted for years. According to researchers, the initial burst of light was powerful enough to knock neutrons out of Nitrogen atoms in the air. Nitrogen atoms can recapture a neutron, and emit more light. However, this secondary process happens less often with time, and corresponds to the decay of the initial signal. The afterglow is a major finding. If a Nitrogen atom fails to recapture a neutron, it can undergo a radioactive decay into a stable Carbon atom. Scientists were able to confirm that this exact decay took place by studying the wavelengths of light in the afterglow.
The discovery of this lightning afterglow is an exciting find for atmospheric scientists. This single observation illuminates a channel by which radioactive isotopes of Nitrogen, Oxygen, and Carbon can be produced in the atmosphere. Of course, more research is needed to determine precisely how much of the atmosphere’s isotopes are produced in lightning strikes. Researchers are also keen to note that there isn’t any danger from the radiation emitted after lightning strikes. After all the signals are so small that they weren’t detected until recently!
Managing Correspondents: Bez Laderman and Karri DiPetrillo
Media Coverage: Lightning can trigger nuclear reactions creating rare atomic isotopes – Science Magazine