An aurora borealis, also known as Northern Lights, illuminates the night sky above the Yllas Fell in … [+]
The sun has been busy erupting in dark plasma explosions and launching big bursts of charged plasma in our direction over the past week, creating improved conditions for viewing the aurora borealis and aurora australis, AKA the northern and southern lights.
NASA and NOAA’s Space Weather Prediction Center has put out a geomagnetic storm watch for Thursday and Friday with the period of strongest intensity coming Thursday when a strong G3 storm is expected.
“A G3 storm has the potential to drive the aurora further away from its normal polar residence, and if other factors come together, the aurora might be seen over portions of Pennsylvania, Iowa, to northern Oregon,” the forecast reads.
The week’s space weather forecast.
The dancing, colorful lights are the result of explosions of energetic particles hurled outward from the sun’s atmosphere called coronal mass ejections (CMEs). Unlike solar flares that travel at the speed of light, CMEs take a few days to reach us and collide with our planetary magnetic field, creating the glowing lights in the sky.
Generally speaking, the stronger the geomagnetic storm, the lower the latitudes where aurora may be visible. A G3 storm means aurora might be seen as low as 50 degrees of geomagnetic latitude.
This particularly favors the northeast quarter of the US, where major cities like Boston, New York and Philadelphia have a decent chance of seeing the lights along with Chicago and Seattle. Of course, getting away from all that urban light pollution would also help with the viewing experience.
A series of CMEs have been seen on the sun since Sunday and began arriving at Earth Wednesday. Combined with a coronal hole that is releasing some extra solar wind, there’s plenty of factors in the space weather environment to get those lights dancing.
Thursday is when we’ll likely see the so-called “cannibal CME” I wrote about previously arriving, which is part of why it’s expected to be a period of strong geomagnetic activity.
While the storm is classified as strong, it’s unlikely to do much damage to our infrastructure in space or the electrical grid on the ground. If it were to ramp up further to an extreme G5 level storm, there could be reason to lose significant sleep.
That’s not expected to happen right now, but the sun has continued to erupt. A pair of CMEs on Wednesday could give us a glancing blow by Saturday, so even more aurora could be in the near future.
