First 'extreme' solar storm in 20 years brings spectacular auroras

The most powerful solar storm in more than two decades struck Earth on Friday, triggering spectacular celestial light shows from Tasmania to Britain — and threatening possible disruptions to satellites and power grids as it persists into the weekend.

The first of several coronal mass ejections (CMEs) — expulsions of plasma and magnetic fields from the Sun — came just after 1600 GMT, according to the National Oceanic and Atmospheric Administration (NOAA)'s Space Weather Prediction Center.

It was later upgraded to an "extreme" geomagnetic storm — the first since the "Halloween Storms" of October 2003 caused blackouts in Sweden and damaged power infrastructure in South Africa. More CMEs are expected to pummel the planet in the coming days.

Social media lit up with people posting pictures of auroras from northern Europe and Australasia.

"We've just woken the kids to go watch the Northern Lights in the back garden! Clearly visible with the naked eye," Iain Mansfield in Hertford, England, told AFP.

That sense of wonder was shared in Australia's island state of Tasmania.

"Absolutely biblical skies in Tasmania at 4am this morning. I'm leaving today and knew I could not pass up this opportunity," photographer Sean O' Riordan posted on social media platform X alongside a photo.

Authorities notified satellite operators, airlines and the power grid to take precautionary steps for potential disruptions caused by changes to Earth's magnetic field.

Unlike solar flares, which travel at the speed of light and reach Earth in around eight minutes, CMEs travel at a more sedate pace, with officials putting the current average at 800 kilometers (500 miles) per second.

The CMEs emanated from a massive sunspot cluster that is...