'STEVE' descends on North America after surprise solar storm
It looks like an aurora, but remains a phenomenon "completely unknown" to science.
In the dark of Sunday night and Monday morning (Aug. 7 and 8), a surprise solar storm slammed into Earth, showering our planet in a rapid stream of charged particles from the sun. The resulting clash of solar and terrestrial particles in Earth's atmosphere caused stunning auroras to appear at much lower latitudes than usual — and, in southern Canada, triggered a surprise cameo from the mysterious sky phenomenon known as STEVE.
Alan Dyer, an astronomy writer and photographer based in southern Alberta, Canada, caught the wispy ribbons of green and violet light on camera as they shot through the sky.
"STEVE lasted about 40 minutes, appearing as the … aurora to the north subsided," Dyer wrote on Twitter(opens in new tab) on Aug. 8. "STEVE was 'discovered' here so he likes appearing here more than anywhere else!"
As Dyer noted, the strange sky glow called STEVE was first described by citizen scientists and aurora hunters in northern Canada in 2017. STEVE is typically composed of an enormous ribbon of purplish light, which can hang in the sky for an hour or more, accompanied by a "picket fence" of green light that usually disappears within a few minutes.
The glowing river of light may look like an aurora, but it's actually a unique phenomenon that was considered "completely unknown" to science upon its discovery. Today, scientists have a slightly better idea of what's going on.
STEVE (short for "strong thermal velocity enhancement") is a long, thin line of hot gas that slices through the sky for hundreds of miles. The hot air inside STEVE can blaze at more than 5,500 degrees Fahrenheit (3,000 degrees Celsius) and move roughly 500 times faster than the air on each side of it, satellite observations have shown.
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