How a solar radiation storm created January 2026's aurora

"Starting on the night of January 19, 2026, planet Earth was treated to a global show that had only been seen once before in the 21st century: a spectacular auroral display that wasn't triggered by a solar flare or by a coronal mass ejection, but instead by a completely different form of space weather known as a solar radiation storm."

"Whereas solar flares normally involve the ejection of plasma from the Sun's photosphere and coronal mass ejections typically involve accelerated plasma particles from the Sun's corona, a solar radiation storm is simply an intensification of the charged ions normally emitted by the Sun as part of the solar wind. Only, in a radiation storm, both the density and speed of the emitted particles get greatly enhanced."

"We're currently still in the peak years of our current sunspot cycle: the 11-year solar cycle that's been tracked for centuries, where "peak years" see 100+ sunspots on the Sun while "valley years" see a largely featureless Sun. While several notable auroral displays have graced Earth in recent years, there's only been one other severe (S4 or higher-class) solar radiation storm this century: back in 2003."

A powerful solar radiation storm on January 19–20, 2026 produced global auroral displays without a solar flare or coronal mass ejection. A solar radiation storm amplifies the charged ions in the solar wind by increasing their density and speed. The event occurred during peak years of the 11-year sunspot cycle, a period of abundant active regions. Severe radiation storms have been rare this century, with a comparable S4 event in 2003. The storm's particles reached Earth in under 24 hours, much faster than typical 3–4 day space-weather transit times. The solar wind forms an extended solar atmosphere that envelops the planets.

Read at Big Think