Meet ‘Steve’ – the fascinating and spectacular purple streak of light in the sky
A strange purple streak of light has been spotted in the sky by a group of aurora fans – who have decided to call it ‘Steve’.
An aurora – or Northern Lights – is a hypnotic display of swirling glowing lights, usually found at the Arctic or Antarctic.
They are caused when charged particles that come from a solar wind emitted by the sun come into contact with the Earth’s magnetic field. The particles are sent upwards into the atmosphere and the charged particles lose their energy, causing them to emit light of various colours.
It creates a spectacular sight and it is no surprise that people travel from all over the world to catch a glimpse of the natural phenomenon.
One such group is the Alberta Aurora Chasers, who posted photos of a mysterious stretch of light at the scene of an aurora. They had referred to the light as a ‘proton arc’.
The photos were seen by Eric Donovan from Canada’s University of Calgary. Donovan knew that the group’s name for the streak of light was not accurate as proton auroras are invisible.
However, he was fascinated by the streak of light and decided to investigate it further with his colleagues. They looked through satellite data from the Swarm mission (the European Space Agency’s mission to study Earth’s magnetic fields).
They believe that the streak could be caused by a hot ribbon of gas flowing in the upper atmosphere.
Donovan said: “As the satellite flew straight through Steve, data from the electric field instrument showed very clear changes.
“The temperature 300 km above Earth’s surface jumped by 3,000°C and the data revealed a 25km-wide ribbon of gas flowing westwards at about 6km/s compared to a speed of about 10 m/s either side of the ribbon.
“It turns out that Steve is actually remarkably common, but we hadn’t noticed it before. It’s thanks to ground-based observations, satellites, today’s explosion of access to data and an army of citizen scientists joining forces to document it.
“Swarm allows us to measure it and I’m sure will continue to help resolve some unanswered questions.”
The group called the stripe Steve as a nod to the 2006 children’s animation film Over the Hedge, which saw the characters give the name ‘Steve’ to a creature that they had never seen before.
Written by Michael Kehoe @michaelcalling