Space Weather and Solar Winds Charge Lightning Storms Here on Earth

Space weather doesn't just impact the International Space Station; it can also affect the weather on Earth. Scientists have discovered that lightning on our planet is triggered by cosmic rays from space in addition to energetic particles from the sun.

"Cosmic rays, tiny particles from across the universe accelerated to close to the speed of light by exploding stars, have been thought to play a part in thundery weather down on earth," said Chris Scott, one of the researchers, in a news release. "But our work provides new evidence that similar, if lower energy, particles created by our own sun also affect lightning."

In order to better understand lightning strikes and what might cause them, the researchers analyzed data on strikes over the UK between 2000 and 2005. This data was restricted to any event that occurred within a radius of 500 km from central England. This data was then compared with information from NASA's Advanced Composition Explorer (ACE) spacecraft, which measures the characteristics of solar winds.

So what did they find? It turns out that there's a link between increased thunderstorm activity on Earth and streams of high-energy particles accelerated by the solar wind.

"Our main result is that we have found evidence that high-speed solar wind streams can increase lightning rates," said Scott in a news release. "This may be an actual increase in lightning or an increase in the magnitude of lightning, lifting it above the detection threshold of measurement instruments."

The sun actually rotates every 27 days, causing high-speed streams of particles to wash past our planet with predictable regularity. Knowing this, researchers can now use this information when making weather forecasts here on Earth.

"We propose that these particles, while not having sufficient energies to reach the ground and be detected there, nevertheless electrify the atmosphere as they collide with it, altering the electrical properties of the air and thus influencing the rate or intensity at which lightning occurs," said Scott in a news release.

The findings are published in the journal Environmental Research Letters.