That stunning purple streak running through the aurora? You can just call it ‘Steve’
Group of Alberta amateur astronomers helps scientists unravel a minor mystery
CALGARY Meet Steve. He’s tall, colourful and photogenic, and up until recently, he’d been relatively anonymous.
Now, Steve is a celestial rock star thanks to a group of amateur Alberta sky watchers who began documenting the breathtaking atmospheric phenomenon that sometimes appears in the northern lights, which now has astronomers taking notice.
“We started shining a light on this a few years ago,” said Chris Ratzlaff, a professional photographer and administrator of the 8,000-strong Alberta Aurora watchers Facebook group.
“Nine times out of 10 it looks like an airplane’s contrail — it can easily go by and you might not see it.”
But thanks to the so-called citizen astronomers of Alberta Aurora Chasers, who began logging the sightings and producing stunning images of Steve — the moniker an homage to the children’s movie Over the Hedge, the same name given to an unexplainable object — it has gained the attention of University of Calgary astronomers, the European Space Agency (ESA) and NASA.
When captured, especially during long exposures with cameras, Steve appears as a massively long brilliant purple streak that occasionally carves its way in the midst of an aurora.
But where Steve was once a mysterious feature of the aurora borealis, it now has an explanation, thanks to the European Space Agency’s Swarm magnetic field mission.
With data gathered by Alberta’s network of aurora watchers, the team was able to pinpoint its appearance for a flyby by one of the mission’s three satellites, and determine what exactly makes Steve tick.
“The temperature 300 km above Earth’s surface jumped by 3,000 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,” said U of C astronomer Eric Donovan in an ESA blog post.
“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.”
According to NASA’s Aurorasaurus blog, there were more than 50 sightings of Steve (which has since been hammered into the acronym Strong Thermal Emission Velocity Enhancement) last year and they’re hoping to gather more data in 2017.
The phenomena has also been reported in the U.K., Alaska, northern U.S. states and even New Zealand.
Nine times out of 10 it looks like an airplane’s contrail — it can easily go by and you might not see it.