Scots were left dazzled – and puzzled – by a rare light display that lit up skies on Monday night.
The phenomenon, called Steve, treated stargazers to purple and green light ribbons over parts of Scotland and north-east England, with one Skye distillery sharing stunning photos of the rare celestial event.
The spectacular glow led many to make comparisons with aurora displays like the Northern Lights, but scientists say that the two phenomena are fundamentally different.
So what were the mysterious lights, and how unusual are they?
Why is the display called Steve?
Steve is said to get its unusual name from a scene in the animated movie Over the Hedge. In the film, a band of animals wake from hibernation to discover an equally odd and impressive phenomenon – a large hedge.
“I’d be a lot less afraid of it if I just knew what it was called,” an animal declares, leading another to recommend calling it Steve. “I’m a lot less scared of Steve,” agrees a third animal.
But Steve is also much more than just a cheeky nickname. Inspired by the film, scientists created a name for the glow by shortening its scientific description – Strong Thermal Emission Velocity Enhancement.
How is Steve formed?
Experts have only been studying Steve since 2016, meaning that little is known about how or why it appears. However, scientists believe that the eerie display is caused by a fast-moving stream of very hot particles called a sub-auroral ion drift, or SAID.
This creates a dazzling light display that lasts between 20 minutes and an hour before vanishing.
How is Steve different to the northern lights?
While Steve often appears during a showing of the Northern Lights, it is entirely different. The Northern Lights appear when electrically charged particles from the Sun enter Earth’s atmosphere and pass energy onto gas atoms and molecules.
These solar emissions in turn heat gas in the upper atmosphere, which creates Steve.
The two phenomena look different too. Unlike the shimmery green oval shapes that make up the Northern Lights, Steve is a narrow arc of purple light that stretches from East to West. Steve is also sometimes accompanied by a row of vertical green stripes that look like a picket fence.
Where and when can Steve be seen?
Steve is unpredictable and only lasts for short periods, so sightings are rare. The phenomenon was last spotted in the UK in November 2023, but has also appeared Canada, New Zealand, and northern states in America according to NASA.
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