Despite the early sunsets and the blistering winter cold, our friend the sun is still hard at work and brimming with activity that can brighten up your dreary nights. The heavenly body, sensing we are feeling low down here on Earth, even released a very large geomagnetic storm that has added to the jam-packed schedule of celestial activity taking over the skies this month.
Thanks to a solar flare and Coronal Mass Ejection (CME) on December 7—basically, when the sun’s corona violently belches billions of tons of plasma along with a magnetic field that sends the material hurtling towards Earth—the northern lights will appear in certain corners of the U.S. this week.
The visual treat will extend further south than it normally does, and be visible in or around cities such as Boston and Chicago, in addition to parts of Pennsylvania and downstate New York. Here’s exactly what’s causing the phenomenon and how to see it streak across the sky near you.
What causes the northern lights?
In general terms, the northern lights are caused by intense storms on the sun’s surface. Charged particles from the sun collide with Earth’s atmosphere, resulting in the vibrant green and pink hues alternately referred to as the aurora borealis or aurora australis.
Great storms on the sun send gusts of charged solar particles hurtling across space. If Earth is in the path of the particle stream, our planet’s magnetic field and atmosphere react.
The event is more commonly spotted in the furthest reaches of the southern and northern hemispheres—hence the terms “northern lights” and “southern lights.” Sometimes, however, the storms are intense enough to send arcs of radiant light cascading over less remote locales, and that’s what’s currently happening this week over broad swaths of the U.S.
This week’s storm
Monday’s solar eruption was very big indeed, and classified by NOAA’s Space Weather Prediction Center as a G3 category geomagnetic storm. Of the various categories of severity marked by the Geomagnetic Storm index (G1-G5), G3 is strong enough to illuminate the skies above the Pacific northwest, parts of the midwest, and northeastern cities like Boston and Providence, as well as areas just outside New York City.
The SWPC issued a Geomagnetic Storm watch for December 9-11, and the strongest displays are peaking at G3 tonight, according to the agency.
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Short of an official map of the northern lights’ projected course, you can refer to this screenshot from the Weather Channel to see just how far the light show is expected to extend. As you can see, it’s no dice for locations below a certain latitude.
How to see the northern lights
There are a few general rules that will help you have a better chance of seeing the event, but keep in mind that nature makes no promises. Make sure you’re as far north as possible, and to surround yourself in as much darkness as you can. Tonight’s show is expected to peak “within an hour or two of midnight,” SWPC scientist Rodney Viereck told the Chicago Tribune, but it will still be possible to catch glimpses before then.
Viereck also recommends seeking out a higher platform to view the spectacle, such as the roof of a building. According to the Tribune, only really northerly places like Canada and Minnesota will see the lights overhead; it’s more likely you’ll catch them in the horizon.
Another important note: If you miss tonight’s show, it’s not like you won’t ever have another chance to see the northern lights. They’re not as fleetingly rare as other celestial events, such as this month’s “kissing” of Jupiter and Saturn, which won’t occur again in comparable terms until 2080. But venturing out into the cold tonight to witness the spectacle is worth doing anyway.
This story was updated on Dec. 10 at 12:31 pm to correct an error in attribution.