By studying particles called muons, scientists found that the electric potential inside a thunderstorm may be 10 times higher than previously thought.
Driving a thunderstorm’s powerful booms and thrilling light shows are amazingly high electric voltages. In fact, those voltages can be far higher than scientists had assumed. Scientists recently found this out by observing an invisible drizzle of subatomic particles.
Explainer: The particle zoo
Their new measurement found a cloud’s electric potential could reach 1.3 billion volts. (Electric potential is the amount of work necessary to move an electric charge from one part of the cloud to another.) That is 10 times the largest storm-cloud voltage previously found. Sunil Gupta is a physicist at the Tata Institute of Fundamental Research in Mumbai, India. The team studied the inside of a storm in southern India in December 2014. To do this, they used subatomic particles called muons (MYOO-ahnz). They’re heavier relatives of electrons. And they constantly rain down upon Earth’s surface.
High voltages within clouds spark lightning. But even though thunderstorms often rage over our heads, “we really don’t have a good handle on what’s going on inside them,” says Joseph Dwyer. He’s a physicist at the University of New Hampshire in Durham who was not involved with the new research.
The previous highest voltage in a storm was measured using a balloon. But balloons and aircraft can monitor only part of a cloud at one time. That makes it tricky to get an accurate measurement of the whole storm. In contrast, muons zip right through, from top to bottom. Those that do become “a perfect probe for measuring the [cloud’s] electric potential,” explains Gupta.
