Eclipses such as 2019's event in South America give a highly-detailed snapshot of the solar atmosphere.
It was once thought that only young and active stars produced these explosive events, but according to a new study, our 4.6-billion-year-old sun also has the capacity.
Although the flare lasted just 10 seconds, it made the star appear about 1,000 times brighter than usual.
While scientists had suspected plasma sheets were unstable, no one had ever managed to characterize that instability until now.
The scientists also say similar shields could already be in use by advanced alien civilizations.