What is STEVE, the Mysterious Ribbon of Plasma in the Sky?

What is STEVE, the Mysterious Ribbon of Plasma in the Sky?
STEVE crisscrosses the Milky Way above Childs Lake, Manitoba, Photo Credit: Krista Trinder/Wikimedia Commons

Citizen scientists discovered the arc of light around five years ago. After much head scratching, we have an answer

Nayanika Mukherjee
March 21 , 2020
03 Min Read

In 2015, a group of night sky chasers spotted something unusual above Alberta. They were amateurs, but they knew it wasn’t the Northern Lights. The aurora borealis is visible from Canada, spreading in broad, elegant curves along the horizon. But this new arc of light was a thin strip, with a distinct beginning and end. The amateurs took several photos, shared them on Facebook (it went viral) and humorously named the unknown phenomena ‘Steve’. Let's just say 2015 to 2017 was a creative time for naming—remember the research submersible christened Boaty McBoatface?

Regardless of the fun name, the photographers and citizen scientists were serious about digging deep, and suspected Steve was a proton aurora. 

An early image of the plasma arc, taken by the group that first discovered it in Alberta

Eric Donovan from the University of Calgary, however, pointed out that proton auroras aren’t supposed to be visible to the naked eye. Correlating the European Space Agency’s Swarm satellite data, which studies the Earth’s magnetic field, with amateur photographs and GPS intel from Alberta, he helped identify Steve for what it actually was—a ribbon of hot plasma 450 kilometres above the Earth, travelling at 6 km/s. And by hot, we mean it’s absolutely smokin’. Steve’s temperature is supposed to be 3000°C. For comparison, the surface of our Sun averages at between 5,500 to 6,000°C.

STEVE beside the aurora KP 8, above Owen Sound in Ontario, Canada

Further research demonstrated how exactly Steve operated. Energetic electrons would pour into the ionosphere, and its friction with existing charged articles would generate heat. It would then create a pinkish glow, similar to how incandescent light bulbs work. Auroras, on the other hand, are formed when electrons shift from high-energy to low-energy states after being hit by ions from solar wind. Steve, thus, was an entirely new optical phenomenon. 

The public (and citizen scientists) had already grown attached to the mysterious idea having a benign name, and so the American Geophysical Union backronym-ed it. Steve became STEVE: ‘Strong Thermal Emission Velocity Enhancement’. We wonder what they would’ve done if it was discovered in India, and the original nickname had been Deepavali, Prakash or Roshni.

STEVE often appears alongside green 'picket fence' auroras

NASA explained that to track STEVE, you have to keep a few things in mind:

> It appears closer to the equator than normal auroras do, around 5-10 degrees farther south in the Northern Hemisphere. It's a narrow arc, aligns east-west, and can extend for hundreds or thousands of miles.

> The glowing display has been reported from the United Kingdom, Canada, Alaska, northern USA and New Zealand.

> STEVE's light is visible for between 20 minutes to an hour, and is mostly purple, pink or mauve. The display is sometimes accompanied by a short-duration green 'picket fence' aurora. 

> STEVE may be seasonal, and has only been spotted near auroras, but scientists don't know the connection yet.

In fact, scientists still don't know enough about the phenomena, but you, as an observer, can help out.  Learn how to spot its future occurrences, and help NASA with research on the way, here, and on Aurorasaurus

Related Articles

A Sky Full of Stars

Gandharv Kamala July 31 , 2019

5 Best Observatories in...

Bibek Bhattacharya October 18 , 2016

Here to there

Explore Directions(Routes) and more...
to Go

Our Other Editions

Outlook’ is India’s most vibrant weekly news magazine with critically and globally acclaimed print and digital editions. Now in its 23rd year...

Explore All
  • Check out our Magazine of the month
  • Offbeat destinations
  • In-depth storytelling
  • Stunning pictures
  • Subscribe