'Canyon of Fire' on Sun Sparks Unexpected Aurora Light Show on Earth
The solar blast took its time getting to the good part.
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Photographer Christy Turner captured the aurora borealis on Sunday near Calgary, Alberta.
A blast of charged particles from the sun created an unexpected geomagnetic storm on Sunday.
The NOAA Space Weather Prediction Center recorded the event as a class G3 storm, which is considered "strong" on the scale that ranges from G1 to G5. The unpredicted storm created glowing aurora borealis that could be seen in northern states in the contiguous US from Maine to Washington.
The storm and associated light show originated with a so-called "canyon of fire" coronal mass ejection, or CME. CMEs are the blasts of charged plasma that often accompany solar flares. This particular one erupted all the way back on April 3, but as it did, it first made a lateral move that appears to carve a deep canyon in the sun's super-heated outer layer.
This NASA animation shows the CME whipsawing across the sun, carving a fiery canyon in the process.
The CME then took its time traveling the distance to Earth, where it collided with our magnetic field last week. That impact is typically what creates auroras, also known as "northern lights" above the equator. But this time the show came later.
"Initially the weak impact on April 8 had little effect, but unrest has been brewing ever since," explains astronomer Tony Phillips at SpaceWeather.com. "We could be seeing the effect of Earth's passage through the extended wake of the coronal mass ejection, which contained unexpectedly strong magnetic fields. A minor solar wind stream arriving during the early hours of April 10 may have helped, too."
Phillips estimates "the glowing walls of the canyon are at least 20,000 kilometers high and 10 times as long."
The storm is over now, but another unexpected blast from our local star could soon bring an encore. On Monday, a fading sunspot proved it wasn't quite dead yet by shooting another significant CME in our direction. It's expected to reach Earth later this week.