Sun's Activity May Cause Lightning Strikes on Earth by 'Bending' the Magnetic Field

The sun may actually be influencing lightning strikes on Earth. How? The sun is temporarily "bending" Earth's magnetic field and allowing a shower of energetic particles to enter the upper atmosphere. In fact, it could be causing as much as 50 percent more lightning strikes in the UK.

The Earth's magnetic field functions as a built-in force field that shields our planet against a bombardment of particles from space, known as cosmic rays. These cosmic rays, however, have the potential to prompt a chain reaction of events in thunderclouds that trigger lightning bolts. This means that influencing the magnetic field could also influence lightning strikes.

In order to better understand how lightning could be influenced by solar activity and the Earth's magnetic field, the researchers examined satellite and Met Office data. This revealed that between 2001 and 2006, the UK experienced a 50 percent increase in thunderstorms when the heliospheric magnetic field (HMF), which is the sun's spiral-shaped magnetic field, was pointed towards the sun and away from Earth.

 "We've discovered that the sun's powerful magnetic field is having a big influence on UK lightning rates," said Matt Owens, one of the researchers, in a news release. "The sun's magnetic field is like a bar magnet, so as the sun rotates, its magnetic field alternately points toward and away from Earth, pulling the Earth's own magnetic field one way and then another."

The findings reveal that cosmic rays may be channeled to different locations around the globe, which can then trigger lightning in already charged-up thunderclouds. In theory, this means that changes to the planet's magnetic field could make thunderstorms more likely by acting as an extra battery in the atmospheric electric circuit.

"Scientists have been reliably predicting the solar magnetic field polarity since the 1970s by watching the surface of the sun," said Owens. "We just never knew it had any implications on the weather on Earth. We now plan to combine regular weather forecasts, which predict when and where thunderclouds will form, with solar magnetic field predictions. This means a reliable lightning forecast could now be a genuine possibility."

The findings are published in the journal Environmental Research Letters.