Lightning, along with severe thunderstorms, is a danger here on Earth, and although we can predict such weather sometimes, we could be missing a key factor in why lightning happens in some areas more than others.

Now, scientists at the University of Reading in the UK think that lightning on Earth is, in part, affected by the pull of the sun's magnetic field on Earth's own magnetic field.

In fact, these scientists discovered that over five years, when the sun rotated and pulled at the Earth's magnetic field, there were 50 percent more lightning strikes in the UK.

Normally, the Earth's magnetic field protects the planet from cosmic rays, which are particles of high-energy radiation carried by the solar wind. But researchers recently discovered that isn't always the case, and sometimes those rays get through and affect lightning and thunderstorms on the planet.

Researchers studied satellite data, as well as other weather data, from between 2001 and 2006. They combined that with what we know about the sun's magnetic field, which flows outward throughout the solar system. The data showed that when the magnetic field pointed towards the sun and away from the Earth, the UK had 50 percent more thunderstorms than normal.

But how does this happen? When the sun's magnetic field changes direction, it pulls on the Earth's magnetic field. This exposes the upper atmosphere to cosmic rays. The sun's magnetic field acts as a sort of bar magnet on Earth's magnetic field, pushing and pulling it as it rotates.

"From our results, we propose that galactic cosmic rays are channelled to different locations around the globe, which can trigger lightning in already charged-up thunderclouds," says lead author Dr. Matt Owens. "The changes to our magnetic field could also make thunderstorms more likely by acting like an extra battery in the atmospheric electric circuit, helping to further 'charge up' clouds."

This suggests that Earth weather is often influenced by space weather, and obviously warrants further study. Future weather forecasts could combine traditional meteorology with space weather information for more accurate forecasts, perhaps even allowing us to predict severe thunderstorms weeks before they happen.

"We now plan to combine regular weather forecasts, which predict when and where thunderclouds will form, with solar magnetic field predictions," says Dr. Owens This means a reliable lightning forecast could now be a genuine possibility."

[Photo Credit: NASA/SDO]