Did you spot STEVE? The rare phenomenon of the aurora borealis' lesser known cousin
A rare phenomenon, the aurora borealis' lesser-known cousin, was spotted across the UK last night, as ITV News' Charlie Frost reports
The northern lights illuminated the skies on Sunday night with the Met Office confirming sightings spread across the UK.
The lights, also know as the aurora borealis, were “observed across Scotland, clearly visible from Shetland webcams, and sightings reported across some central and eastern parts of England”, the Met Office said.
But another rare phenomenon has been spotted dazzling star-gazers, the aurora's lesser-known cousin, STEVE.
What is STEVE?
A strong thermal emission velocity enhancement, also known as STEVE, was spotted over skies in the UK on Sunday night.
The atmospheric optical phenomenon is caused by a flowing ribbon of hot plasma breaking through into the earth's ionosphere, appearing in the sky as a purple, red and white arc.
First named by aurora watchers in Canada in 2016, it is relatively new to scientists, according to US space agency NASA.
What is the difference between STEVE and the aurora borealis?
Despite appearances, STEVE differs to the northern lights as it is formed of a thinner, single arc-shaped band, rather than the more "spread out" look of the aurora borealis.
According to the European Space Agency, a typical aurora is caused by energetic electrons traveling down Earth’s magnetic field.
When those electrons collide with the atmosphere roughly 100 km above Earth’s surface, they excite atoms which then emit red, green, and violet light.
In contrast, STEVE does not appear to be caused by energetic electrons, and is white, purple and red in colour.
How to spot STEVE? UK star-gazers will be pleased to hear that STEVE can be spotted further south than the usual aurora borealis.
The Met Office said the lights were seen across Scotland on Sunday, with sightings also reported in central and eastern parts of England.
In general, looking to the north you should give you the best chance of seeing the lights - a cloudless, clear night is also ideal.
But if you didn't catch last night's spectacle, scientists say there will be more opportunities in the future to witness the phenomenon.
Where is the best place to witness the northern lights?
On Sunday the Met Office said the best chances to see the northern lights, also known as aurora borealis, were in Scotland, but “it could be possible as far south as central Wales and England”.
Professor Don Pollacco, department of physics at the University of Warwick, said the phenomenon was caused by “the interaction of particles coming from the sun, the solar wind, with the Earth’s atmosphere – channeled to the polar regions by the Earth’s magnetic field.
“It’s actually a bit like iron filings and the field of a bar magnetic.
“The solar wind contains more particles when there are sun spots, as these are regions on the sun’s surface where the magnetic field is interacting with the plasma in the sun, and the particles can be released.
“Once the particles are channelled into the Earth’s atmosphere they interact with molecules and have distinctive colours (eg: oxygen molecules produce green light, nitrogen red light etc.) and patterns such as light emissions that look like curtains or spotlights.
“These shapes change quickly over timescales of minutes/seconds."
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