STEVE
Aurora chasers in Canada kept photographing a purple ribbon in the sky that scientists couldn't explain, so they named it Steve.
What was reported
For years, members of an online group of aurora photographers in Alberta shared pictures of a narrow ribbon of purple or mauve light stretching east to west across the sky, sometimes with a 'picket fence' of green streaks below it. It didn't look like an ordinary aurora, and it appeared farther south.
In 2016 they showed it to scientists, who didn't recognise it either. The photographers had nicknamed it Steve, after a scene in the film Over the Hedge; scientists later turned the name into an acronym, Strong Thermal Emission Velocity Enhancement.
Explanations offered
Satellite measurements showed Steve is a fast-flowing stream of very hot charged particles high in the atmosphere. Research in 2019 suggested it isn't technically an aurora at all, because it isn't caused by particles raining down from space. Exactly how it glows is still being studied.
- When
- Studied from 2016
- Where
- Near Calgary, Alberta, Canada
- Witnesses
- Amateur aurora watchers in Canada
- Status
- Partly explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.