In the dark night of Sunday to Monday morning (August 7 and 8) a a surprising solar storm crashed into Earth, showering our planet with a rapid stream of charged particles from sun. The resulting collision of solar and earth particles in The Earththe atmosphere caused a stunner aurora borealis to appear at much lower latitudes than usual – and in southern Canada prompted a surprise cameo from the mysterious celestial phenomenon known as STEVE.
Alan Dyer, an astronomy writer and photographer based in southern Alberta, Canada, caught the thin bands of green and violet light on camera as they shot across the sky.
“STEVE lasted about 40 minutes, appearing as … the aurora borealis to the north died down,” Dyer wrote on Twitter (opens in new tab) on August 8. “STEVE was ‘discovered’ here, so he enjoys appearing here more than anywhere else!”
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As Dyer noted, the strange celestial aurora called STEVE was first described by citizen scientists and aurora hunters in northern Canada in 2017. A STEVE typically consists of a huge band of purple light that can hang in the sky for an hour or more, accompanied by a “fence” of green light that usually disappears within a few minutes.
The glowing river of light may look like the aurora borealis, but it is actually a unique phenomenon that is considered “a complete stranger” of science when it was discovered. Scientists today 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 cuts the sky for hundreds of miles. The hot air inside STEVE can burn at more than 5,500 degrees Fahrenheit (3,000 degrees Celsius) and move roughly 500 times faster than the air on either side of it, satellite observations show.
While the northern lights occur when charged solar particles collide with molecules in Earth’s upper atmosphere, STEVE appears much lower in the sky, in a region called the subauroral zone. This probably means that the solar particles are not directly responsible for STEVE, Live Science previously reported. However, STEVE almost always appears during solar storms like Sunday’s, appearing after the northern lights have already begun to fade.
one hypothesis suggests that STEVE is the result of a sudden burst of thermal and kinetic energy in the subauroral zone, somehow triggered by the collision of charged particles higher in the atmosphere during auroral solar storms. However, more research is needed to uncover STEVE’s true secrets. In the meantime, we can just bask in its ethereal glow and wave back at its glistening green fingers.
Originally published on Live Science.
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