Meet Steve – A strange, new 'purple aurora' that lights up night sky

This strange ribbon of purple light named 'Steve' was so first observed by citizen scientists in Canada and eventually verified by the European Space Agency (ESA).

By Zee Media Bureau | Updated: Apr 27, 2017, 10:44 AM IST
Meet Steve – A strange, new 'purple aurora' that lights up night sky
Photo credit: Dave Markel via European Space Agancy

New Delhi: A strange, yet mysterious aurora has been discovered recently – thanks to a group of citizen scientists chasing the northern lights and social media.

This strange ribbon of purple light named 'Steve' was so first observed by citizen scientists in Canada and eventually verified by the European Space Agency (ESA).

Astronomer Eric Donovan of the University of Calgary came across something he hadn't seen before while looking at photos on the Facebook group of the Alberta Aurora Chasers. The group called this strange purple streak of light in the night sky captured in their photographs a ‘proton arc’, but Donovan knew it had to be something else because proton auroras aren't visible.

However, nobody knew what it actually was so they decided to put a name to this mystery feature, which they called it Steve.

While the Aurora Chasers combed through their photos and kept an eye out for the next appearances of Steve, Prof Donovan and colleagues turned to data from the ESA's Swarm magnetic field mission and his network of all-sky cameras.

Soon he was able to match a ground sighting of Steve to an overpass of one of the three Swarm satellites, says a release from the ESA.

“As the satellite flew straight though Steve, data from the electric field instrument showed very clear changes. “The temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westwards at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon,” Prof Donovan told ESA.

“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,” Prof Donovan said.

“Swarm allows us to measure it and I’m sure will continue to help resolve some unanswered questions,” he added.

Speaking at the recent Swarm science meeting in Canada, Prof Donovan explained how this new finding couldn’t have happened 20 years ago when he started to study the aurora.